PART III.

THE Ds LOCUS

TRANSPOSITION OF THE Ds LOCUS .

+ ¥ tpindiy € Firakcsgs ay fet -
April, 1949

The De locus. Part III, Transposition of the Ds locus.

Outline

l. Introduction Code omen eeeesecerecesesseceseecssceees Page
2. The origin of transposed DS, Case I ssecccevnceseesss Page 2
5, Cytological examination of plants in culture 4628 ... Page 5
4, The genetic analysis of the Plants in culture 4628
(a), Sub-culture Cc PoC e reece seneeesereseeesvesess Pape 7
(bb). Sudeculture D .rscscccccvecvccsevevsceecvecees Page 10
{c), Sub-culture F Creer recererenoreevescsoceseves Pare 12
(4), Sub-culture ¢ thee renee vesosesservecevecseess§ Pase 15
fe). Submoulture H cccscsccccusccscucessecescecces Page 17
(£1), Gubmculture I vissccccccccccccsvccccceveccecs Page 18
CG). Submculture K sicesccccccsccccsccecsvcceuccecs Page 19
(nh). Sub-culture L Pere eeceesoenrereceseccecessece Page 21

5. Considerations of the events responsible for the

transposition of the Ds locus Pee eoewcereseesenvene§ Pare 24
THE Ds LOCUS. PART ITI. TRANSPOSITION OF THE Ds LOCUS

1. Introduction

Transvosition of the Ds locus is a relatively frecuent
phenomenon, In the report on the origin and behavior of the c+ml
locus, it was shown that oem) arose from a normal © locus as the
consequence of a transposition of a Ds locus from its standard
location in chromosome 9 to a position close to or within the ¢
locus. The presence of the transposed Da locus did not produce
any alteration in the appearance of the chromosome in the re-ion
where it had been inserted, nor did its oresence cause any reduc#
tion in crossing-over between C and Sh. In this new location, Ds
responded to Ac in exactly the same way that it responds to ac
when in ite standard looation, The relation of this resnonse to
the production of visible mutations of ceml to ¢ was discussed in
the earlier report, The study of c-ml mutational phenomena
sugsested that the Ac-controlled mutable loci arise because of
transpositions of the Ds locus, Since these transpositions are
relatively frequent, it say readily be understood why so many new
Aceoontrolled mutable loci are arising in the Ds, Ac plants and
why previously stable "wild-type" loci "suddenly" become unstable
and mutable,

Secause transpositions of Ds are related to the origin of
mutable loci, it is of prime importance to determine the mechanism
responsible for this transposition, How docs it oceur and why
does it ocour with such relatively hich frecuencies? An extensive

analysis of one case of transposition of Ds has indicated the
whe

probable mechanism that brings about this transposition, The
analysis also suggests the reason why these transpositions are
so frequent. This case of transposition of Ds will be considered

in detail in this report,
&. The origin of transposed De, Case I

The first recognized case of transvosition of Ds arose in the
oross of 4 plant (4108C-1) having the constitution wd I Sh 2g Wx Ds
in one normal chromosome 9 and Jd C sh bz wx as in a nornal homolosous
chromosome 9, This plant was heterozygous for ac (Ae ac), “he
tynes of kernels resulting from the cross of this plant to a female
pliant carrying C sh bz wx ds aoc are given in table 1. (The male
parent plant (4108C#1) arose from an I - © bz, Sh = sh, wx-wx kernel
on an ear coming from the cross of a C sh bz wx ds ac female plant
by an Ac ac male plant having two normal chromosomes 9 with
dd C Sh Bz 4x Ds and wd I Sh Bz Wx ds, respectively. The kernel
from which plant 4108Cel arose was selected becsnuse it had received
an I Sh Bz dix Ds chromosome, The Ds locus was introduced into this
chromosome as a consequence of crossing-over in the heterozyzous
male parent.) As table 1 shows, with the exception of two aberrant
kernels, the types of kernels and the ratios obtained are those
expected on the basis of the above given constitution of this plant.
“hen this plant was crossed to a ¢c sh 32 wx ds ac female plant,
the types of kernels appearing on the ear are those viven in table 2,
The ratios of the various tyoes of kernels obtained in this cross
likewise agree with the given senic constitution of the male parent
Plant (4108¢=1; see suvplement to table 2), In both erosses,

the variegation in those kernels having both Da and Ac is of the
Table 1
Types of kernels appearing on ear from cross of

C sh bz wx ds ace x i Sh Ba wx De ag we g
C sh ba wx ds

Plant 4108-1]

 

 

 

Kernel type Number of kernels

Iet bz, Sh*, Wxewx $7

I Sh Wx 59

C sh be wx 128

I sh wx 5

C Bu=C bz, Sh,Wx=wx 5

C¢ Sh Ba wx 2

I Sh wx 52

C Ba-C bz, sh, ix=wx 0

C sh Bz Wx 1

C sh ba, #xowx 22

C sh ba Wx 31

IeC Be-C bz, Sh, Wxewx 1 Origin of Plant 4806

I-c Bz,3h = 1 Not tested
Totals 364

 

* The Shesh variegation will not be indicated in the table.
It may be understood to be present,
Supplement to Table 1
Types of chromatids produced by plant 4108C#1 and appearance of
kernel in table 1

J a 3 4
I Sh Bz Nx De

 

Aa ac

 

Cc sh »bs Mex «6s

Appearance of kernel
Ac i-C bz ,Sh-sh, éx-wx 5?

Non Cross-over I Sh B bz Wx Da
chromatids ac I Sh Wx

C sh bz wx ds <Ae and ac C sh be wx

 

 

 

 

 

Region 1 I sh be wx ds Ac and ao I sh wx 5
yp ae C Bac bz ,Shesh, W¥xewx 5
C Sh Ba Wx Ds
“ae C Sh Bg 4x g
Region 2 I Sh bz wx de Ac and as I Sh wx
vy Ae C BaeC bz. sh, 4x-wx 0
C sh Bz Wx Ds -
‘ ae ¢ sh Bz ix 1
Region 3 I Sh Bs wx ds ao and ac I Sh wx
7 ae C sh bz lxewx 22
C sh bz wx Ds
“ ac C sh bz Wx 31
Region 4 I Sh Bz 4x ds Ac and ac I Sh Wx
C sh bz wx Da Ac and ac C sh ba wx

 

Observed double cross-over, Regions 2 and 3:-1 C sh Bz wx non-variegated

Odd classes = 8, See Table l.
Table 8

Types of kernels appearing on ear from cross of

I Sh Bz Wx Ds

cc sh 3gwx ds ac? x A@ ae ad

 

C sh b2 wx ds
Plant 4106C-]

 

 

 

Kernel type Number of kernels
IeC 82, Sh* Wxewx 41
I Sh dx 68
C sh wx 86
I sh wx 4
Cee, Sh  Wxewx 3
GC Sh ix l
I Sh wx 48
C#o, ah, /xowx 14
C ah ix 24
I sh 4x 1

Totals 290

 

162 I : Leec
152 Wx : 138 wx

* he Shesh variegation will not be indfoated in the table
but may be understood to be present,
supplement to Table 2

Chromatids produced by plant 4108C-l and appearance of kernels:

 

 

 

 

 

 

 

I 3h Wx Ds
Cross-over regions tested:
C ah wx aie
1 2 3
Cross-over — Resulting Critical
region Constitutions of ¢d gametes kernel type kernels
AG leo Sh Wxo-wx 41
' I Sh Wx Ds “
™“~ aco I Sh Wx
Non=-crossovers
C sh wx ds Ao and ao C6 sh wx
I sh wx a0 and ac I sh wx 4
Region 1
_ AG Cee Sh sxewx 3
QO Sh ax Ds
Nae C Sh wx 1
I Sh wx ds Ao and ac I sh wx 48
Region 2
— ae Ceo sh ixewx 14
C ah Wx Ds
\ ae C sh Ax 24
I 3h ax ds Ae and ac T Sh ax
Region 3
AQ Cea sh wx 0
C ah wx Ds ~—
Nag C sh wx

 

Regions 1 and 27 11 sh 4x (De ac),
=~ Su

type exvected when a Ds locus is at its standard position in the

I Sh Bz 4x chromosome, The Ds mutations gave rise to © sh bz wx
sectors (table 1) or o sh wx sectors (table 2), Also, the position
of this Ds locus is obvious from the types and frequencies of
recovered cross-over chromatids shown in tables 1 and 2, ‘There can
be no doubt that in plant 4108Ce-l, Ds was located to the right of
WX,eeat its standard location in the wd I Sh Bz i/x chromosome,

One of the two exceptional kernels listed in table 1 showed a
type of variegation that would not arise from an I Sh fz %x Ds order
of senes, In this kernel, many chromosome breaks of the [s muta-
tional type had ocourred, but the position of the breaks was just
to the right of the I locus instead of to the Tight of the <x locus,
These breaks gave rise to cells in which the I locus was Sliminated
but the Sh Bz and Wx loci were retained, Following such a Ds
mutation, a dicentric chromatid was formed that had sh Bz and Jx
in the short arms of the two terminally fused chromatids (the dicentric
chromatid), Continued breakage-fusion-bridge cycles resulted in
successive deletions of these loci in some of the descendent cells.
Consecuently, within the ¢ Bz Wx sector sub-sectors of ba and, Wx were
present, inother type of vartesation was also present but the
deacrintion of the variegation types will be postponed until lster
when correlations of the senic organization of this chromosome with
the varievation patterns can logically be derived,

The aberrant kernel was planted in the greenhouse in the winter
of 1947-48, No cytological examination was made of the plant arising
from this kernel for fear of injury, Secause the vlant was very

early in maturing and because no other plants were available for

crossing, only a self-pollination of this Dlent was possible. The
whe

types of kernels appearing on this self-nollinated ear are given in
table 3. The chromosomal and genic constitution of the aberrant
chromosome 9 carrying I Sh 32 4x in this vlant has been determined
from an analysis of the plants arising from the kernels on this
self-pollinated ear. This analysis makes the types of kernels that
appeared on the ear readily interoretable, “eosuse the kernels are
quite different from those arisine in vrevious studies, a sunolementary
analysis giving the chromatids that could »>e produced during meiosis
in this slant and the tyves of gametes that will result accompanies
table 3, This plant had a normal chromosone 9 carrying © ds sh bz wx ds
Wor Canad
and a Duplication chromosome 9 with wd and 1, ased 3h Bz ux in each of
the two duplicated segments (see diacram, table 3 supplement).
Synhapsis between the two chromosomes 9 usually occurs as siven in the
diagram anc the crossover percentazes between the marked loci are
not reduced, as the genetic analysis of the Fe plants that were
heterozygous for this duplication will show, The "ds" desienstion
is meanineless with respect to the presence of any true allelic loci?
It has been inserted to make the constitutions easier to read ata
Glance, Eecarse of the many possible classes of crossover chromatids
that could arise in this plant, only the single crossovers between
the two chromosomes 9 following synapsis of the distal duplicated
segment in the Duplication chromosome 9 with its homologous segment
in the normal chromosome 9 are siven in the supplement to table 3,
Double crossovers in the region between C and wx are relatively rare
and will be neglected at this point in the discussion, ‘The single
erossovers, however, are frequent and are most important in interpreting
the constitutions of the observed types of kernels. althoush it was

realized from the tynes of kernels on the séelf-pollinated ear that
Table 3

oar
Types of kernels appearing on self-pollinatéen of Plant 4306
wa I Ds Sh Bz Wx Wx Bz Sh Ds

 

 

Constitutions ee 2

WaC ds sh bz wx ds

 

AG ac

 

 

I kernels Cc kernels
I Sh Wx 81 C Sh Bz Wx 4
I Sh Wx-wx 6 C Ba-C bz, Shesh, Wx-wx 3
Imo Bz-C ba, Shesh, Wx-wx 73 C sh bz wx 89
IeC Bz, Sh Wx
I Sh wx 4 Total : 274
I-C Bz-C bz, She-sh, wx 10 178 I: 960
I sh wx 2 168 Wx : 106 wx

I bz-C bz, sh wx i

 
Supplement to Table 3

Types of chromatids produced by plant 4306. Nonecrossover ami sincle cross-over

chromatids resulting from the usual type of synapsis. The expected appearance of

the kernel if combined with a C sh bz wx ds chromosome in Ac ac ac or ac ac at
constitution

o hoa oa ee
te
wi ' 4 3 Os t
ner # = coenew cee eee ete aminmmne

 

 

 

 

Li””~*~«Ssédgs Bh bz wx ds rr
én Appearance of kernel
-Chromatids:
‘ wy Ao IeC BueC bz, Sh, Wx-wx
Non=crossovers I De Sh Bz ax ¥#x Bz Sh Ds ~~
Duplication ac I Sh ¥x
C ds sh bz wx ds Ac and ac C sah bz wx
normal
Ids sh bz wx ds Ac and ac I sh wx
normal
Region 1 \ .- Ac C BaeC bz, Sh, Wx=wx
Cc De Sh Bz 4x Wx Be Sh Ds _
Duplication ac C Sh Bz Wx
Ac I bee bz,sh wx
Region 2 I Ds sh be wxds —~
normal ™ ge I sh wx
Ac C BaeC bz, Sh, Wxr-ws

C ds Sh Bz Wx Wx Bz 3h Ds
Duplication ac

2

Sh Bz #x
Supplement to Table 3 continued

 

 

 

 

 

\ _- Ao I be-C bz, Sh wx
Region 3 I Ds Sh bz wx ds
normal “ae I Sh wx
2 Ac C BzeC bz, Sh, Wx-wx
C ds sh Bz Wx Wx Bs Sh Ds ~
Duplication ac ¢ Sh Bs Wx
\ Ao I-C Ba-C bz, Sh wx
I Ds Sh Be wx ds
Region 4 normal] ac I Sh wx
1, ac C Bu-C ba, Sh, Wx—wx
¢ as sh bz Wx Wx Be Sh De ©
Duplication ac C Sh Bs Wx
\ _- Ae ImC Bz-C ba, Sh, Wxewx
I Ds Sh Be Wx da
Region 5 normal \ ae I Sh Wx
1, Ae C Bz-C bz, Sh, Wrewx
C ds sh bz wx 4x Bz Sh Ds ~
Duplication ac C Sh Bea Wx
Region a ' 1 Ac I-C Bz-C bz, Sh, Wx=wx
Not considered Wa I Ds Sh Bz 4x Wx Bz Sh Ds
in table Duplication \ ge I Sh Wx
wd C ds sh bz wx ds Ac and ae 2 sh ba wx

normal

 
~5S—

(1) a Da locus had been transposed just to the right of the I locus
and that (2) some chromosomal aberration involving the region to
the right of the I locus had likewise occurred, the exact nature of
the aberration was not clearly understood from the analysis of this
ear alone,

To obtain exact information on the aberration that occurred and
its possible relation to a transposition of Da, some of the kernels
in the various classes represented in table 3 were planted in the
summer of 1948 under culture number 4628, With respect to Wd or wd
and BZ or bz, the types of plants arising from these various classes

of kernels are given in table 4.

3. Cytological examination of plants in culture 4628,

Cytological examination was made of a number of plants in the
various sub-classes of culture 4628, The sporocytes in some of these
plants gave very poor figures, Those in which the constitution of
ohromosome 9 was clear and readily analyzable are summarized in
table 5. In subecultures D and £, the majority of plants probably
had the same genic as well as chromosomal constitution as the mother
plant. All the examined plants had one normal chromosome 9 and a
chromosome 9 with a duplication of a mid-segment of the short arm,
This duplicated segment was inserted into the short arm, Homologous
synaptic association of the short arm of the normal chromosome 9 with
the short arm of the Duplication chromosome 9 usually occurred slong
the distal two-thirds of the arm, «4 loop configuration in the
Duplication chromosomes 9 was present. Its position varied in the
different sporocytes but it was usually close to or within the deep-

staining region adjacent to the centromere. None of this proximal
Table 4

Appearance of plants in culture 4628 obtained from selected gemmme-nf kernels on self-
pollinated ear of plant 4306 (table 3)

 

 

Sub-culture Appearance of kernel Wamber of
desig-~ in each sub-culture kernels iad ahr Sordi Ranta arising
nations from which plants arose planted
A Ie-C Bz, Sh Wx 1 O No shoot developed; onl “roots
B I Sh Ax-wx 2 2 white seedlings (wd/wd)
Cc I Sh Wx 20 17 «4d, Be : 1 white : 2 no sermination
D I-C Ba-C bz, Shesh, Wx wx 158 15 Wd, Bz
(Many C bz wx areas)
E I-C Bz-C Bz, Shesh, Wx-wx 10 8 Wd, Bz: 1 white : 1 no germination
(Few C be wx areas)
F I Sh wx 2 2 wd, Bz
G I-C Bz=C bz, Sh-sh, wx 3 3 Wa, Bs
(Many C bz areas}
(Few C bz areas)
Z I sh wx 2 2 Wa, bz
d I bz-C bz, sh wx 1 1 #d; died in seedling stage
K C Sh Bz Wx 2 2 Wa, Bz
L C Bz-C bz, Shesh, Wx-wx 2 2 4a, Bz
M C sh bz wx 20 6 Wd, bz

 
Table 5
Constitutions of chromosomes 9 in plants of culture 4628 based

upon examination of sporod:ytes at pachytene.

 

Plant Number Constitution of chromosomes 9 Constitution of

 

in examined plant plant from pollen
examination

4628C~ 9 2 Duplicationg chromosomes 9 Wx Wx

4628C-17 1 Duplication chromosomes qx wx
1 Normal a *

4628D-10 1 Duplication “ " 4X wx
1 Normal +. a

4628D-11 1 Duplication " “ ax wx
1 Normal ~ 2

4628D-12 1 Duplication Wx wx
1 Normal

4628E- 8 1 Duplication xX wx
1 Normal

4628F- ] 2 Normal WX wx

4626F~< B 2 Normal Wx wx

4628G~ 3 & Normal wx wx

4628G~- 2 2 Normal Wx Wx

4628H~ 1 2 Normal wx wx

4628H- 2 2 Normal WX Wx

46281~ 1 1 Duplication ax wx
1 Normal

 
abe

deep-staining re-ion, however, was included in the duplicated
segment,

Plant 4628C~9 was homozysous for the chromosome 9 with the
duplication, y comparative measurements of the short and long
arms of chromosome 9 in this plant and from the appearance of the
chromomeres within this arm, it was apparent that the duplication
was composed of a segment approximately equivalent in length to a
third of the normal short arm, It was composed only of the smaller
chromomeres characteristic of the distal two-thirds of the normal
short arm, It was concluded (1) from the chromomere constitution
in the plant homozygous for this duplication, (2) from the synaptic
phenomena in the heterozygous plants and (3) from the genic and
chromosomal constitutions of the Fo population that the duplicated
segment was composed of a section of the middle of the short arm of
chromosome 9 and of a length approximately one-third of this arm,
This segment had been inserted into a normal short arm, ‘This may be
diagrammed, without reference to order of genes, as follows:

Normal chromosome 9 short arms 3 apabrewore

ee -{- eee ap fees : OF So Rerttey BPN

Duplication chromosome 9

short arm! - 2 >
mA a _ . caaeme ced

woe aa wr ee of .

Plant 46281e1, arising from a kernel having a cross-over ay
chromatid, was heterozygous for the Duplication chromosome 9,
Synaptic behavior between the normal and the Duplication chromosome
9 was similar to that described for the heterozyzous Plants in

subecultures Dand E, The plants in sub-cultures ¥, G and H, on
aye

the other hand, had two morphologically normal chromosomes 9, No
abnormalities of any kind could be seen in the chromosomes 9 of
these plants, In all of these plants, however, the I, Ds, Sh and
Bz loci in the normal chromosome 9 had originally been located in
the Duplication chromosome 9 of the mother plant,

A genetic analysis of the plants of culture 4628 has made it
possible to state (1) the genic composition of the two identical
seements in the Duplication chromosome 9, (2) the order of the genes
in each segment and (3) the probable event that occurred in a cell
of plant 4108C <1 which produced the duplication and the transposition
of a Da loous from its standard position to a position immediately
to the right of the I locus, The purpose of the following description

is to give the evidence that allows these conclusions to be drawn.

4. The genetic analysis of the plants in culture 4628, (a), Sub-
culture C,.

 

Pollen examinations were made of a number of plants of culture
4628 (table 6), This was particularly important in sub-culture C in
order to select those plants that could be expected to be homozygous
for the Duplication chromosome 9, These plants should be jx Wx.
Only 3 Wx Wx plants were present in this sub-culture, Because plant
C=9, a ix Wx plant, had also been examined cytologically, it was
selected for tests to determine the types of variegation patterns that
the De loci in the Duplication chromosomes $ would produce, This

plant was crossed to the following female plants:
Table 6

#x and wx constitutions in plants of culture 4628 based on

pollen examination

 

Sub-culture fx We" Wx we wx wx Appearance of kernels from
which plant arose

 

eames

Cc 3 14 0 I Sh vx
D 0 3 0 I«C Bz +C bz, Shesh, Ax=wx
E 0 1 0 I= C Bz -C bz, Shesh, (x=wx
(few C be areas)
¥ 0 0 2 I Sh wx
G 0 0 3 I-C Be -C bz, Shesh, -wx
H 0 0 2 I= C Bz, Sh-sh, wx
(few C bz areas)
Z 0 Q 2 I sh wx
K 0 2 Q C Sh Bz ¥x
L 0 2 0 C Ba- ¢ bz, Shesh, Jx-wx

 

* All 3 plants had a few, emall, partially filled wx staining
pollen grains, This is to be expected from De® mutations (see
Anmual Report, 1948),
~G—

(1) ¢ ah bz wx ds, ac ac

(2) C sh bz wx ds, Ac ac

(3) o sh Bz wx ds, ac ac

(4) C Sh Bz wx Ds / C Sh Bs wx Ds, Ac Ac
(5) C Sh Bz wx os f C Sh Bz wx Ds, ac ac

When crossed to C sh bz wx ds ac female plants, two tyves of
kernels appeared on the ears in eoual ratios, One was I Sh dx
and non-variegated. The other tyne of kernel was variegated (table
7a), All these variegated kernels had sectors that had lost the
I locus, Hany of the sectors were C Bz Wx in phenotype but within
the sector varlagation for C bz was oresent. These C bz areas were
all wx, Within the C Bz sectors there were often large wx areas
that were definitely Bz and not bz, This 1 important, as will be
indicated later. There were also some C bz wx sectors, not within
or associated with the C Bz sectors, It was evident that two types
of events were occurring in these kernels. Both involved loss of
the I locus but one gave the C Bz Ax sectors with C bz wx and Bz wx
areas within them and one gave C bz wx seotors directly. Further
analysis has made it clear that these two separate types of varie-
gation are associated with the presence of two Ds loci in the
Duplication chromosome 9, one (De) located just to the right of
the I locus and one (Ds”) losated to the right of the proximal
duplicated segment. A De® mutation accounts for the appearance of
the indevendent C bz wx sectors; a Dst mutation gives rise to the

C Bz 4x sectors with a secondary tyne of variegation within them,

as described above; C eroded. mw Iealbengs - ge Iudlap ee
fotlswing 3 fowwelin thy cueowline Suowalia a
nen, ).
Table Yaa

 

1 a Fi y £
C eh bz we ds ac? x LDS" 3h Ba dx Wx Bg Sh De Ao ac ¢
I Dat Sh S82 Ax x Bg Sh De®

Plant 462809

Kernel types

 

 

Cross I Sh ix ImC Ba-C ba; Shesh, ix-wx*
4361-5 x 46280-9 222 212
4363-10 x" " 18 16
4362C-6 x * " 273 256

Totals 513 464

 

* See text for soourate description of variegation.
Table 7=»b

e eh Bz wx ds ac 2 x «4628649 oO

Kernel types

 

Colorless
Cross Colorless Sh-sh
dh Wx :
Wx=wx

 

4347-19 x 4628C-9 180 189

 
Table 7c

C sh bz wx ds, Ac ac 9 x 46285-9

 

 

 

 

ne a
not obviously . Odds
variegated Speckled Ac ac ac
{Ae Ac Ac and (Ac 4c ac) type
ac ac ac)
4462C-11] x 46280-9 190 121 140 /-
x
4462c~e, x " " 171 115 110 1 ¢ Sh Be wx
non-varie-
gated
Totats | 3 61 36 _ &sO

* Some of the kernels in this column have a few small © areas or a

few specks of C.

oN La PG os yom
wR Rasy tages EK Se PTET unset VAST

® ‘ ‘ : a Py .
Qu bo ees A i ef beetle,
Table 7d

C Sh Bz wx Ds / C Gh Ba wx Ds, Ac Ac 2 x 4628C6-9 ¢

 

I Wx I-C, Wxewx I-C, vxewx

 

Cross not obviously
van peated Ac Ac ac type Ac ac ac *
4380R-6 x 4626C-9 25 36 4

|
'

ei
4 Sen Wopat on fe Deus {or dupa ahvou qe a
=Q=

The evidence obtained from this cross alone is not sufficient to
establish the “Sonstitut ions of the chromosomes 9 in this plant
(4628C-9) as given in table ?-a, The analysis of the other plants

aga

in culture 4628 allows ie “constitutions of the chromosomes 9 in
this vliant to be designated with a high degree of certainty. The
constitution of the Duplication chromosomes 9 are, then:

I Ds) Sh Be #x Wx By Sh De®,

That no C locus was present in the duplication chromosome 9
was indicated from the cross of 4628C-9 to ec sh Bz wx ds ac female
Plants (table 7b), All of the kernels resulting from this cross
were colorless, No colored spots or areas were seen in any of then,
Half of them, however, were jx «- wx variegated, as expected. Ifa
C locus had been present to the right of net, then its presence
should have been detected in the 4x - wx variegated kernels on this
ear. It seems reasonable to conclude, therefore, that no C locus
was present in the Duplication chromosome 9, That none should be
present will be indicated when the projected event that save rise
to the duplication is discussed,

Plant 4628C+9 was crossed to a C sh bz wx ds, Ao ac female
plant, table 7=c, If plant 4628C-9 were Ac ac in constitution, as
the evidence in tables 7a and 7-b indicate, the endosperm consti-
tutions of the kernels represented in table 7eo should be 1 Ac 4c Ac 3
I Ac Ac ac : 1 Ae ac ac : 1 ac ac ace Responses of the Ds loci to
Ac dosage would determine the classes of kernels appearing on this
ear, The ratios of classes, with respect to variegation pattern,
in table 7c, are those that could be anticipated. The observations
suggest that some of the ac ac AG constitutions allow a very Light

sveckled pattern of variegation to sppear--a few very late Da muta-
wo Ow

tions were ocourring in some of these kernels, Table 7#& gives the
tyves of kernels obtained from the cross of 4628C-9 to a C Sh Bz wx Ba
C Sh Bz wx Da, Ac Ao (allelic positions) female plant, again, the
classes of kernels appearing on the ear following this cross are in

agreement with the projected constitution of the male parent,
(bd), Sub-culture D

The tested plants in sub-culture D were all heterozysous for the
Duplication chromosome 9, The selection of this class of kernels
from the self~nollinated ear of plant 4306, would suggest that they
micht have similar chromosome and cenic constitutions as the mother
plant. Two of these plants were crossed to C sh be wx ds ac female
plants, The results of these crosses are given in table 8, Because
of the many classes of kernels that could appear following this oross,
a supplement to table & has been included to show the types of
chromatids that these plants could produce, if they had the siven
chromosome 9 constitutions, The types of chromatids are the same as
those that have been considered for the parent plant. (Supplement to
table 3), In these crosses, however, a direct test for the presence
of these various types of non-crossover and crossover chromtids is
available, It may be seen from the suyplement to table & that
crossing over would produce morphologically normal chromosomes 9
having a transposed Ns locus. The constitutions of these chromosomes,
in the single cross-over classes, would be: I De! sh bz wx, I Ds 3h bz wx
and I Ds 3h Bz wx, The variegation pattern that each of these chromo-
somes would produce in the cross to ¢ sh bz wx ds is apparent, They
appear in table 8 under the designated headings I ba=C bz, sh, wx,

I baeC ba,Shesh, wx and IsC Ba«C bZ, Shesh,wx, respectively. If plants
Table 8

1 gue 2
C ds sh bz wx ds

 

 

 

T3E5zE Grogs =~ _ |
Kernel type x x x x Totals
4628D~-10 4628D-10 4628D-11 4628D~11

I Sh Wx 38 55 37 70 200
IeC BeeC bz, Sh*, Wx-wx 16 27 40 59 142
T th wx 22 29 13 30 94
I-€ BzeC ba, Shi, wx 8 16 19 33 76
I bzeO ba, Sh, wx 1 1 1 0 3
I sh wx 3 5 2 8 18
I bzeC bz, sh wx 1 3 2 6 12
C Sh Bz Wx 20 16 16 27 79
C BaeC bz, Sh, Wxewx 10 7 ? 19 43
C Sh Bs wx 0 0 i 2 3
C sh bz wx  6F 115  — 108 — 220 500

Total kernels 1170

 

* The Shesh variegation will not be indicated in the table but may
be understood to be present.

545 I: 625 C
2¢5 Was BS ky
Supplement to Table &

Types of chromtids produced by ¢ plants in table 8, Only single cross-overs in designated
synapsed region considered.

 

 

 

 

 

, ® 3
4+ + 4 M 5
tpsl sh Be * ax We Bz Sh Ds“
+ O- ia
C ds sh bz wx ee
“Om
Appearance of kernel
in Table 8
~ Ae I-C Bu-C bz, Sh, Vxewx
Non-crossovers I Ds? sh Bz ¥x Wx Bz Sh Ds” ~
Duplication ac I Sh Wx
C ds sh bz wx ds Ac and ac C ah bz wx
normal
Cross-overs I ds sh bz wx ds Ace and ac I ah wx
normal
Region 1 >
AG C Beet ba, Sh, Wx—wx
c ps! sh Bz Wx Wx Bz sh Ds? < 7
Duplication ac C Sh Bz Wx
1 _ AG I ba-C bz, sh wx
Crossovers I De+ sh be wx ds
Normal ~ ac I sh wx
Region 2
C ds sh Be wx Wx Be sh De® - ac G BaeC bz, Sh, #x-wx
a £ “
Duplication ~ ae C Sh Bs Wx

 
Supplement to Table & continued

 

 

 

Crossovers le _ Ae I be-C bz, Sh, wx
I Ds~ Sh bz wx ds
Region 3 Normal “ae I Sh wx
- Ao C Ba-C ba, Sh, Wx-wx
C ae sh Bz ax dx Be Sh Ds® —
Duplication ac C Sh Bz ax
Crossovers Ac IeC Bue bz, Sh, wx
I Det sh Bz wx as — , ,
Region 4 Normal “ae I Sh wx
. 2- Ao C Be-C bz, Sh, Wxewx
¢ ds sh bz vx Wx Bz Sh Ds
Duplication “ae C Sh Bz wx
Crossovers — ac I-C Be-C bz, Sh, Wxowx
I Dest sh Bz dx ds
Region 5 Normal “ac I sh Bs dx
2 AC C Bz-C bz, Sh, /x-wx
C ds sh bz wx ix Bz Sh Da” ~
Duplication Nac C Sh Ba ax

 
eile

were grown from these kernels, all should possess two normal
chromosomes 9, The selection of the C Bz «= C bz, Sh = sh, 4x = wx
kernels, on the other hand, should sive rise to plants with a normal
ehromosome 9 carrying C sh bz wx ds and a Duplication chromosome 9
with the various constitutions indicated in the supplement to

table 8, Because the region between Bz and ix is the longest, the
most frequent of the cross-over classes should be;:normal chromosomes 9
with I De? Sh Bz wx and Duplication chromosomes $ with C ds sh bz dx
Wx Sh De® (crossover region 4, supplement to table 8), Crossing over
ratios may be determined in regions 2, 3 and 4 by comparing the
frequencies of the various classes of I kernels showing variegation,
The numbers in the I bz = C ba, sh wx class, (region 2), the

I bz - C ba, Shesh, wx class (region 3) and the I + C Bz -C bz,
Shesh, wx class (region 4) are 12 : 3: 76, respectively. The
crossover units for regions I to sh, 3h to Bz and Be to /x in normal
chromosomes 9 are approximately 3: 2: 21, respectively. The
agreement in the two cases in relative frecuencies in the several
orossover recions is close, No serious disturbance in the relative
frecuencies of crossing-over in these regions 1s occurring in the
Plants that are heterozygous for the duplication,

Moreover to test the projected constitutions of the zametes
produced by plants 4628D-10 and 11 (table 8) 4t would be necessary
to grow plants from the various classes of kernels in this table and
test the chromosomal and genic constitutions of the chromosome 9
contributed by the male parent, f#ecause the constitutions of the
ciromosome 9 in the gametes of the mother plant (4306) were probably
the same as those produced by the two tested plants of sub-culture D,
the probable constitutions of the plants in subecultures * to L can

be anticipated,
(tate 3)

On the self-pollinated ear of plant 4306, the various crossover
Classes of kernels of the tyves indicated in table 8 were likewise
present. The chromosome 9 constitutions of the examined plants ar'sing
from a selected number of such kernels has been given in table 5, The
correspondence of chromosome constitution with expectancy on the
basis of the selection was confirmed by the cytolozical analyses,
Plants in sub-cultures G and H of culture 4628 should carry two normal
ehromosomes 9, one with I Ds 3h Bz wx and one with ¢ ds sh ba wx,
these plants should be Ac ac, as the type of variegation observed in
the kernels from which they arose would suggest, The plants in sub-
culture F should have the same two chromosomes as plants in sub
cultures Gand H but these plants could be either ac Ac or ac ac,

The plants in culture I, not examined cytologically, could be expected
to heave two normal chromosomes 9, one with I Ds sh bz wx (an I ds ah
bz wx chromatid is infrequently produced) and one with C ds sh bz wx,
These plants could be ac Ac or ac ac. The exact senic constitutions
of chromosomes 9 in the plants in subd-cultures K and L could not be
projected in advance other than to anticivate the presence of the
duplication chromosome 9 resulting from a crossover in recions z to 5,

and chromosomal constitutions of these plants will now be civen,
{c) Sub-culture F

Sy aopropriate crosses of plants in sub-cultures F to L, the
genic constitutions of the two chromosomes 9 in each tested plant
Was determined, Plant 4628F-1, known to have two morpholosically
normal chromosomes 9 because it was examined cytologically, was

crossed to two C ds sh bez wx ds ac female plants. The tyves of kernels
~13=

appearing on the two resulting ears are given in table 9. This

plant was obviously Ae Ac (allelic positions) in constitution,

The supplement to table 9 indicates the types of chromatids that plant
4626F-1 would produce on the basis of the given constitution, The
observed ratios of the various classes of kernels on these ears
confirms the projected conatitution of this plant. The plant had a

normal chromosome 9 with I pet

Sh Bz wx and a normal chromosome 9
with C ds sh bz wx. The Ds locus is present just to the right of I,
It should be noted that crossing-over between IJ and Sh is not affected
by the presence of this Da locus (4.9% crossing-over).

d#ith the same aleurone genes in chromosome 9,the variegation
pattern produced by a Ds locus in this new position is strikinsly
different from that produced by a Ds locus in its standard location,
In this new position,a 9s mutation will give an acentric fragment
carrying I and a dicentric chromatid with Sh Bz wx, as shown in the

following diagram:

I Sh 82 wx

) ( ;

I Sh Rg wx

 

The dicentric chromatid produced by a Da mutation at this locus will
undergo the breakage-fusion-bridge cycle beginning in the ananhase
followins the Ds mutation. In this first anaphase, the genes 3h and 32

will be located alose to the middle of the bridge:

o .

me Bz 3h sh Bz NX

Because the bridge may be broken at any position between the two

centromeres, it can be anticinated that some of the breaks in this
sh" “Sas ah be wx
Cc oh bz ds ac? x —1_De 3h Be ac Aca] © %S Sh bz wx

Table 9

{ dL 4

Cross of 4628Fe]
t
I De $h Be wx

 

 

 

 

“€ ds eh bz 4628F=1
Kernel type Crossover 4368Ca4 4563-14 Totals
region x x
4628F] 4628F=]

IeO Ba-C bz, Shesh nonec,o, 181 89 &70
C ah bs nono ,6, 153 83 236

Regions 1&2
I sh Region 1 1 1 2

Regions 1&8
C BaeC ba Sheesh Region 1 0 1 1
I beeC bz, sh Region 2 8 4 12
¢ 3h Bz Region 2 6 6 12
I bz-C bzy Shesh Region 3 10 6 16
C ah Bz Region 3 2 3 5
I sh Regions 182 9 0 9*
C bay Shesh Regions 1&3 i 0 1
I Bz-C bzy sh Regions 2&3 0 0 0
C Sh bz Regions 2&3 0 0 0

Totals 371 193 564

 

* This class ia not accurate for showing cross-over regions,

It

includes (1) losses of Ac and (2) loss, transposition oy changes in

state of Dea
t l s

}

Supplement to Table 9 yy 4
I Da 3h Bz

 

Chromatids produced by plant 4628Fr-]

DAAC DEN TNE TS

C ds ah bz

 

 

 

 

 

 

 

 

Chromatid

constitutions Appearance of kernel in table 9
Non-crossovers I Da 3h Be IeG Bz-C ba, Shesh

CG ds sh bz C ah bz
Cross-overs I ds sh bz I sh
Region 1 C De Sh Da C BaeC bz, Shesh
Cross<overs I De sh bz I bzeC bz, ah
Region 2 C ds Sh Bz C Sh Bz
Crossovers I Ds Sh bz I ba-C bay Jhesh
Region 3 C ds sh Ba C sh Pz
Double cross-overs I da 3h Bz I Sh
xeeions 1 and 2 C Ds sh bz Cc sh bz

I ds sh Be I sh
Revions 1 and 3

C Da Sh bz GC bZ, Shesh

I Ds sh Bz I Bs-C bz, sh

Regions £ am 3
C ds 3h bz Cc Sh bz

 
~14=

division will occur to one side of this Bz Sh Sh Bz segment instead of
within this segment, This would give rise to two daughter cells, one
containing no Sh or Bz locus and one containing two 3h and two Bz
loci, The I locus, carried by the acentric fragment, would be lost

to both daughter cells:

 

 

 

 

 

A B
x
Gq,
No I, Sh or Bz No I loms; two 3h;
loos two Bz loci

These two sister cells should give rise to two adjacent (twin)
sectors in the endosperm, one having a C bz phenotype and one having
a C Bz phenotype in which © bz areas appear. These C oz areas would
arise from the continuation of the breakage-fusion-bridge cycle in
cell 3B that was initiated by the original Ds mutation:

|

Bz Sh 3h Ba Bz Sh Sh Bz

 

 

 

Bz Sh Sh Bz o
o--—
C —— — ‘ r ,

Bz Sh Sh Bz

Metaphase t Subsequent
Anapha se
“ break ‘

Cell B os CellB
Twin sectors of the type diagrammed above were present in all of
the variegated kernels in table 9.that received an I De Sh Rz wx
chromosome from the male parent, This variegation pattern is very
striking and is strong evidcnee for tha presence of a Ds locus just
to the right of the I locus, That this location is correct, is
obvious from the genic constitutions and accompanying variegation or
lack of variagation in the crossover chromatids recovered from plant
4628F-1 (table 9),

Plant 4628F=2 had the same chromosomal and genic constitution
as plant 4628F-] with respect to the aleurone genes carried by the two
chromosomes 9, When crossed to C sh bz wx ds ac female plants, no
variegated kernels appeared (table 10a). When crossed to a
C sh bz wx ds,ac ac plant, again no regular variegate! kernels
appeared (Table 10-b), From this cross, it may be concluded that
Plant 4626Fe2 has the constitution I Sh Bz wx / C sh bz wx. It does
not carry a Ds locus that is regularly producing a dicentric chromatid
carrying genes in the short arm of chromosome 9, That a Ds locus may
be present was suggested by the presence of a small amount of varie-
gation appearing on a few of the kernels represented in table 10-b,
This plant may have a newly transnosed Ds locus or a Ds locus with
a changed state giving few if any dicentric chromatids (extreme
few-late Ds?), These possibilities will be tested this summer,

(4d). Sub-culture ¢

Plants 4628 Ge], Ge2 and Ge3 proved to be similar tn the chromo~-
somal and genic constitutions of their chromosomes 9, All had a norzal
chromosome 9 with I Ds Sh Bz wx and a normal chromosome 9 with

GC ds sh bz wx, All were Ac ac, Table ll«a shows the tyves of kernels
C sh bz wx ds ac 9 x 4628%-2 I "Ms" Sh Bz

Table l0-a

*

¢ de eh bz

Kernel typea

3

 

 

Cross I sh I ah C Sh Bz C sh Bz C sh bg
4363-2 x 4629F2 115 6 6 3 84
446804 x 4628F-2 219 15 23 6 226
44620~-9 x 4626-2 210 14 12 13 215
Totals 544 35 41 228 523

 

Total kernels: 1165

% See WaT
Table 10-b

C sh bz ds, Ao ac 2 x 4688F=2 ¢d

 

. Kernel, types

I Sh I sh » © Sh Bz C ah Bz C sh bz
6.0, region 1: 0.0, Region 1 o.0, region 2

 

 

 

460 8 12 4 ee

 

Total kernels: 3428
a} 6a

appearing on the ears following the cross of these plants to

C sh ba wx ds ac female plants, The results obtained are similar

to those recorded in table 9 with resnect to the types and frequencies

of the chromatids that were produced by the heterozygous parents,

Beeause of the ac ac constitution of these plants, the presence of

Ds may be detected in only half of the kernels that received a

chromosome 9 carrying a Ds locus. The variesation patterns in the

kernels having both Ds and ic are the same as those appearing on

the ears from similar crosses involving plant 4628-1 (see page \3 ),
In table ll-b, the types of kernels are civen that resulted

from the cross of two of the 3 plants in sub-culture G to c sh 82 wx dg

ac female plants. Crossing over is normal in frecueney in the I to

Sh segment, as indicated in both tables ll-a and li-b (5.5% und 3.9%,

reapectively). Among the 1243 kernels in table ll-b there were

only 2 that were ¢ to c verlegated, Both kernels carried 3h in the

C De chromosome, In table llea, there were only 3 C Bz - ¢ bz

kernels on the esr among the 1461 kernels, All three carried Sh in

the C Ds chromosome, The chromatids carrying ¢ Ds Sh Bg wx should

represent the cross overs that occurred in rezion 1,--between I and Ds.

These 5 cases in tablea llea and ll«b, represent spproximately one-«

fourth of the crossovers in this region that are expected to be

present on these ears, If it may be ass:ned that there are 20 cross~

overs in the region betveen I and 9s among the 2704 kernels oh these

ears, the cross over percent in this recion 1s anproximutely 0.74,

The 0 varlerated kernels on these ears will be olanted this summer

and the individuals arisine from these kernels will be tested for the

presence of a Ds locus just to the right of the 7 locus in order to be
Table ll-ea
c ant as as @ x I Ds Sh BZ WX 45 no G

C ds ah be wx

 

4567B=2 4360A<-2

4563<1

436314 4462C-8 4664-3

 

 

 

Kernel type x x x x x x Totals
4628G—1 46286~2 4628G-2 46286-2 4628G-3 46a%6-3
I=-G Buel bz, Sh 107 19 18 38 108 61 351
I Sh 109 26 25 32 106 48 546
C sh bz 202 45 25 53 219 97 641
I sh 7 3 2 4 5 1 22
C Bz=C bz,Sh 0 1 0 1* 0 1** 3
¢ 3h Bz 8 2 2 0 17 6 35
I bz-C bz, sh 8 1 2 2 12 1 26
I baeC bz, Sh 3 0 1 0 6 2 12
Cc sh Bz 10 2 0 4 6 3 25
C bay Shesh 0 0 0 0 0 0 0
C Sh bs 0 0 0 0 0 0 0
I-C Bz-C bz,sh 0 0 0 0 0 0 0
Totals 454 99 73 134 479 220 1461
Summary: 757 I: 704 C Crossing-over I to Sh = 5.5%
AK yee | Re hs ea Heck evn keds suse

Guo leé ke oe wh BA Me ge. retaica

ro
2A

d
4
ee

wages t

f

re “peed
Supplement to table ll«a

' ee

3
1 oY
1’ De’ Sh’ Bz

Fe

 

 

 

 

 

 

 

 

C sh ba ds ac 2 x Ac ac d |
@ ds ah bz
Le
Non-crossover , Ae - I-¢ Ba-C bz, Shesh 351
chromatids De Sh BE
ac = I Sh
ds ah bz Ac and ac ” C sh b2
Crossovers ds sh bz ac and ac - XY sh
Region 1 pare - GC BaeC bz, Sheesh 3
Dea Sh Bz
‘ae * C Sh Be
Crossovers . pac 7 I be-C bz, eh 26
De sh bz
Region 2 ‘ac = I sh
4s Sh Bez Ac and ac » C Sh Bz
Crossovers ne - I ba-C bz, Shesh 12
Ds Sh bz
Regton 3 ‘ac - I 3h
ds sh Bz Ao and ae = CG sh Bz 25
Double crossovers:
ads Sh Bz Ac and ac = I Sh
Regions 1 and 2
Ds sh bz Ac and ac #* C sh bz
Regions 1 and 3 ds sh Bz Ac and ac «= I gh
yp Ao - C bz, Shesh 0
Ds Sh be
Nac = C 3h bz 0
Regions 2 and $3 phe = I BueC bz, sh 0
Ds sh Bs
Vac = I sh
ds Sh be aAc and ae = C Sh bz 0

 
Table ll#b

i Da Sh
C ds sh
4628G-] and G=-3

¢sh B82 ds aoc 2 x Ao ac d

 

4353-2 4347-22 4355-14 4347-43

 

Kernel Crosseover
x x x x Totals
type regions 46260~1 4628643 4628G-3 4628043
Non 6,0, AG and ac
I Sh 195 167 14? 74 583
Regions 1 & 2
Ae and ac

 

Non ¢.6, ao and ae

C 3h 197 157 169 88 611
Regions 1 & 2 ac

 

Region 1 Ac and ac
I sh il 6 12 4 32
7 2 Ac and ac

 

Cxc Sh Region 1 Ao 1 1 0 0 2

 

Region 1 ac
C Sh “ 2 7 2 4 15
Region 2 Ae and ac

 

 

 

Cee sh Regions 1 and 2 Ae 0 0 0 0 0
Totals 406 338 329 170 1243
| ud Supine ue % 2 = COTO,
*K \ a uy { ; VA ELE woe SE

“Ak ALL AAAI

of
ae _ ae S ewpen av dled
aS * Qe QLAAMLLEN vay ' Rade edad uD fe < a glee
“L7~

sure that no event other than Ds mutations were resnvonsible for

the appearance of the 5 Bz - C bz or C to c variegation in these
kernels, The presence of the Sh locus in all five of these kernels
strongly supports a © Ds Sh constitution that arose from a crossover

in region l.

(e). Subeculture H

Tests of the genic constitutions of the two normal chromosomes 9 in
each of the two plants in sub-culture H are not extensive. Plant
4628H-] was crossed to a C sh bz wx ds, Ac ac female plant, ‘The types
of kernels appearing on the resulting ear are given in table l2<a, The
genic constitutions of the chromosomes 9 in this plant are the same
as those in plants Fel, G-1, Ge2 and G=3 (I pst sh 3z wx / C ae sh
bz wx). Plant 4628H-] should be Ao ac from the appearance of the
kerne] from which it arose. The kernels of the ear should be Ac Ac Aq,
Ac Ao ac, Ac ac ac or ac ac ac, The variegation pattern on the kernels
coming from this cross indicate the presence of these various Ac
constitutions, In the Ac Ac ac kernels, the presence of an I Ds Sh Bz
chromosome was detected by the numerous speckles of C Bz phenotype.

In the Ac Ac ac kernels carrying an I Ds Sh bz or I Ds sh bz chromoe
some, the sveckles of 0 ba could not be detected, The color contrast
is too faint, In the Ac ac ac kernels, however, the C bz color may
be seen for many large sectors of this phenotype are present,

Table 12a does not give satisfactory data, therefore, on the presence
or absence of Ds in some of the kernels having an I De sh bz wx or an
i De Sh bz wx chromosome, The variegation pattern in the Ae ac ac
kernels that received an I Ds Sh 82 chromosome is like that deseribed
for similar crosses involving plant 4628F-1, Crossing over between

I and Sh is normal in frequency (3.6%),
Table lea

I Ds Sh Bz wx
C sh bz wx ds, Ac ac 9 x en A Ae

C ds sh bz wx

 

 

 

4462047 4628H~)
Kernel type Number of kernels

zon (ee rey 10
IeO BueC bz, Shesh 172
Toh (Gee obrtouly 10"
I ba-C bz, sh 2
I b&-C bs, Shesh 1
coh ag (Bot, obviousry
C ah Bg 9
C Sh bz 1
C sh bz 220

Total 525

 

* I Ds sh bz, Ao Ac ae constitutions not distinguishable
because color in ¢ bz specks 1s not deep enough,
Table 12-b

ec Sh Bz wx ds
acac @ x LDDs. sh BZ wx aoe ac ;

CG sh bz wx ds C da sh ba wx

4365=3 4628H-1

 

Kernel type Number of kernels

 

I Sh 139
IeG BueC bz, Shesh 68
I sh 4
I ba-C bz, Shesh 3
C sh Bz 5
C BaeC bz, Shesh 2
C sh bz 103
Co 3h Ba 127

Cee Sh Bz e**

 

& Sake &., ta Mag WER o é seaman LAU q *

ie = Sone EGA. - dads
} é ; 1 es oh Ho tay 2 A,

Lam}

KK wee Cok YEO due tay - tll CU aay
»15—

Plant 4628H-1 was ulso crossed to an ac ac female plant having
a rearranged chromosome 9 with c Sh Bz wx ds and a normal chromosome 93
with C sh bz wx ds, The types of kernels appearing on this ear are
given in table 12-b, These types and thelr relative frequencies are
expected from the given chromosomes 9 and Ac constitutions of vlant Hel.
The constitution of plant 4628H=2 was not examined by outcrossing
to appropriate tester plants. Its constitution is very probably the
game as that of Hel. This was sugzested by a cross of this plant
to one having a om-] locus, the’ types of kernels were Santos. on the

resulting ear and will not be described,

(ft). Subeoulture I.

The two plants in sub-oulture I (those arising from I sh wx kernels,
table 3} were crossed to a series of tester plants. Plant 4628I-1 had
two normal] chromosomes 9, Both chromosomes 9 carried ° sh bz wx,

This conatitution suggests that heterofertilization had occurred or
that the kernel from which this vlant arose had been misclassified,

It may have been a G sh bz wx kernel with poor C bz color develovoment,
The © ba color in the kernels on the ear of vleant 4306 and on the ears
in crosses of the plants in culture 46298 is, however, very well
developed, Classification for C bz phenotypes are distinct. Plant
462612 had two normal chromosomes 9, one carrying I De sh bz wx and
one carrying C ds sh bz wx. This plant was ec ac. When crossed to a
C sh bz wx ds ac female plant, no variegated kernels appeared on the
ear (table 1gce le “hea crossed to a seine" / C Sh Ba, Ae Ao plant,
91 of the 04 kernels recelving—an—tehremosome were I-@ variezated
{table 13-0), when crossed to a C Bz / C bz, ac ac female plsnt,

109 of the 198 I carrying kernels were either I - C Bez or I bz - C bz
Table 13<4

I Ds sh bz wx ;
C sh bz wx ds ac 8 x fae eh eee 8c ae

 

 

46261 ~2
Cross XI ah ¢ sh
non-vari egated non-vari egated
4363-5 x 462812 145 120

44620-3 x" 7

 

Totals

 
Table 13=b

C Bz / C bz, Ac ac? x 4628%~2 <!

”

I kernels ¢ kernels

Cross I, non-varlegated | Teo varie
| gated

437203 x 46281~2 99 109 835
Table l3<e

wr T Wo oy by oy

 

 

 

 

 

¢ ah Wx
Re oe ao Ac 9 x «A46z8r-2 #7 C de ah by uy
C Sh wx
or
nT
oo. 2 kernels, Shwx |
at : ii
Cross Colorless, 3h wx lec ¢ sh dx) C sh wx I sh dx
non-variegated variegated
|
4380A-3 x 46281-2 1 39 44 66 «70
4380j9-8 x nl 8 53 90 | 59 51
Totals 3 fl 4K

 

Odds; 1 sh wx; 1 I sh wxj 1 possible Cec sh ix *

¥# Be AS ASAT ay “4 { aces vin q

RO Do va Shea Kos ranal :
Table 158d

c/a, Ao Ao x 4628 Te? ¢

 

 

 

Cross I kernels C kernels
Cee variegated C, non-varie~
gated
4354-5 x 4628I=2 42 1 70
4354-6 x " " 108 0 100

 

Totals 150 1 170

 
~19—

Variegated (table 13-6), This plant was also crossed to a c / Cy

Ac Ac female plant. Among the 171 C kernels on the ear, only 1

appeared to be C = o variegated (table 13-4), This latter kernel

showed only very late Ds mutations~-a uniform pattern of ¢ specks~~-
characteristic of Ds mutational responses to two doses of this particular
Ao locus, The evidence from all of the crosses indioate the correctness of
the given constitution of plant 46281~2,

The constitutions of the plants in sub-cultures ¥, G, Hand I, that
arose from the I carrying class of crossover chromtids on the selfe
pollinated ear of plant 4306 (table 3), are those exvected from the
given constitution of this parent plant, A summary review of the
constitutions of these plants is e¢iven in table 18. The recinrocal
erossover classes, those carrying the duplication and having a C locus
instead of an I locus, should be revresented in subcultures F and L,

The genetic analysis of these latter plants has siven the final evidence
that is required to substantiate the projected nature of the event that

brought about the transposition of the Ds locus,
(@). Sub-culture Kk

The constitution of plant 4628K-1 (Duplication chromosome 9 with
C da sh bz Wx Wx 32 3h De® / normal chromosome 9 with C ds sh bz wx ds,
Ao Ao) was determined by the tyves of kernels appearing on the ear when
this plant was crossed to a © sh bz ds ac female plant (table l4-a),
All but three of the © Sh Bz Wx kernels were C Bz « ¢ bz, Shesh, ix-wx
varlegated, In these kernels, there were no extensive wx sectors reru-
larly appearing in the C Bz areas, Also, all bz areas were wx and
where sh could be recognized, all were sh, Thia tyne of variezation

would indicate that only one Ds locus was present and that it must be

located to the right of the duplicated segment¢,
Table l4aa

C sh bz weds ac? x G 48 sh ee ax Wx Bz Sh De® AG Ao ¢

44626-3 4628K~1

 

d8 Duplication chromosome 9 dt Normal chromosome 9

 

 

C Sh Bz Wx C BaeC bz,Shesh!' C Sh* bz wx! C sh beg Ax C Bh bz wx

 

 

 

 

not Wxewx
obviously
variegated
io +
: 154 | (2 8 _323%*
fr ener
* 3h is possibly, not positive = nh ‘elro!i4y GH TH YEILE
* l of these is very dark in bz color Vee © bye,
** 6 of these have very dark bz color
C ds sh bz Wx’ Wx Bz Sh Ds
Duplication chromosome 4

 

Normal chromosome . to
C ds sh bz wx

Cross-overst Duplication: C ds sh bz wx 4x Bz Sh Ds®
Normal chromosome: C ds sh bz 4x ds

rma ix, We glioad
Normal chromosome class (minus 2 uncertain C 3h bz wx kernels): 331

Crossovers : 2.44
Table 14<b

Qe e ¢ 5h Bz wx ds
C ds sh bz wx ds

ac ac Y x 4628Ke] ¢

 

 

 

 

 

 

4365-1
2 chromosome: C sh ba wx ds @ ehromosome: c Sh Bz wx dg)
¢ Duplication chromosome 9 | ¢ normal chromosome 9 ¢ Dupl.chr.9 (dé nor. chr .9 ae
“ Odds

C 3h Bs dix | BueC bz,S3h-sh, ¢ sh bz ¥x C sh bz wx) Cea@,Sh Bx [C Sh Bu wx
Non-varie- WX=Wx iXewx

gated . 4 ,_ L

5 | 56 4 150 65 122 2 broken C wx 2 /

© Sh Be Wx De 2
-20=

€<— Eight of the C sh ba kernels were ix, None of these, however,
showed any 4x to wx variegation, In order to rapidly visualize the
tyoes and fresuencies of chromosomes 9 constitutions that the gametes
of this plant could have, a diagram of the usual synaptic association
of the two chromosomes 9 in this plant and the resulting tyves of
cross-over chromatids, is included with table l4ea, It may be seen
from this diagram that the 8 C sh bz Wx kernels could arise from
erossing over in the region of the arrow--between the distal #x locus
and the point that marks the beginning of the proximal duplicated
segment, These chromosomes--oarrying C sh bz ix=-should be normal in
morphology and should have no Ds locus, Therefore, no /x « wx varie-=
gation should appear in the kernels receiving such a chromosome, As
stated above, no 4x « wx variecation appeared in the C sh bz jx kernels,

This same .lant was crossed to an ac ac female plant having the
rearranrced chromosome 9 with ec 3h Bz wx ds and a normal chromosome 9
with C sh bz wx ds (table 14-b). In this cross, the 65 C + ¢,3h Bz
Wx ~ wx kernels arose from fusion of a female nucleus carrying the
c 3h Bz wx chromosome with a male nucleus carrying the Dunlication
chromosome, in the resulting varlersted kernels, all the oc sreas were
wx, No extensive wx sectors regularly appeared in the C areas, Again
this shows that the Ds locus in the Duplication chromosome 9 of the
male parent -ust be to the right of the Wx loci,

dith recard to chromosomes 9, plant 46282 had the same genic
and chromosomal constitution as plant Kel. It was, however, ac ac,
Nhen crossed to ¢ sh bz wx ds ac female plants (table 15-a) or to ¢ sh
32 wx dg ac female plants (table 15-b), no variecated kernels
appeared, “There were only three types of kernels on the ear in each

of these two crosses, On the basis of the civen constitution of
Table 15<a

C sh bz wx ds ac? x C48. 8h bz ix Wx Bz 3h Ds (Dupjac ac ¢

C ds sh bz wx(normal)

 

 

 

4628K <2
d Duplication
Croas chromosome 9 ___.¢, normal chromosome 9
@ Sh Bz Wx © sh bz Wx  C sh ba wx
non-variegated
436l<-11 x 4628K-2 124 ; 4 132

 

Crossovers in sh class: 3%
Table 15<b

6 sh Be wx ds ac 2? x 4628K=2

 

 

 

C Duplication
ha chromosome 9 | Normal chromosome 9
G Sh Bz Wx C_ sh Bz Wx C sh 32 wx
4347-6 x 4628K<2 167 | ‘3 214

 

Crossovers in sh class: 1.4%
Table 15<c

C sh bawx ds, ac ac @ x 4628K-2

é

 

Duplication chromosom 9

Normal chromosome 9

 

 

Cross tinea
C Sh 82 Wx C Baec bz, Shesh, Wx-wx | C sh ba Wx (C sh bz wx
 non-varie- | Non-varie~
gated | gated
44620-2 x 4626K=2 70 | 63 15 213

Crossovers in sh class: 5.7%

 

 
a Pla

Plant 4628kh=2, only three types of kernels are to be expected, The

C sh ix kernels. in both tables, should have a normal chromosome 9
carrying C sh bz x that arose from a crossover in the region between
the distal jx locus and the position that marks the beginning of the
proximal dunlicated seement, “This crossover distance is 3% and 1.4%
of the C sh kernels in tables 1l5«a and 15=b, resnectively, and is
similar to that observed for the sane region in plant 4628K=1,

dhen plant 4628K=2 was crossed to a © sh be wx ds, ic ac female
plant (table 15<c) approximately half of the kernels receiving a
chromosome 9 carrying C Sh Bz Wx were C 32 = ¢ ba, Sh = sh, Wx = wx
variegated, There were 13 C sh bz #x kernels (5.7% of the C sh bz
class) and agzin none of these 13 kernels showed any ix to wx
variegation, As explained above, variegation is not expected in
these kernels,

Plant 4628K-2 was crossed to an Ac ac plant carrying ¢ sh Ba Wx Ds
in a normal chromosome 9 and c sh Bz wx ds in a rearranged chromosome
9 (table 15-d), The appearance of the 79 C « ¢ variegated kernels
in the Sh Wx class is exnected from the given constitution of this
plant. (Serregation of these 79 Cwe kernels into the 2 classes,

Sh Wx and Sh-sh, Wx-wx, has not been indicated in the table.) These
C=o kernels have Ac Ac ac constitution, The Ds mutations occur late

in develonoment, as might be exnected.
(nh), Subculture L

Plant 46281-1, which arose from a ¢ Sh Bz Ax kernel of table 3,
carried C ds Sh Bz Wx Wx Bz Sh De® in a Duplication chromosome 9 and
¢ ds sh bz wx ds in a normal chromosome 9, Two allelic Ac loci were

present (Ac Ac). This plant was crossed t> a © sh bz wx ds ac female
Table 1l5«d

e ¢. sh Bz wx ds
ac ac 2@ x 4688K-2 o

 

ec Sh Bz Wx Ds

 

 

 

4435—=]
C Sh Wx | C sh ix
Cross ln non-varie- | C=e, Sh(+sh }* and
gated wx lowx) C sh wx
non-varie-
geted
' |
4435-1 x 4628K-2 20 79 se

 

* Some kernels are Shesh and Wxewx variegated; others are not,

as expected from constitution of 9,
Zoe

Plant (table 16-a) and to three o sh Bz wx ds ac female plants

(table 16-b). The types of kernels appearing on the ears of these

test crosses have made it possible to write the scenic constitution

of the chromosomes 9 in this plant. Crossing over between the normal
chromosome 9 and the Duplication chromosome 9 in the region of the distal
duplicated semment occurred frequently and was normal in relative
frequencies between the marked loci, ‘The percentages in the marked
regions are given in tables lé-a and 16-b, The explanatory supplement
accompanying each of these tables will make this evident.

No Wx - wx variegation or extensive wx sectors regularly appeared
in the C §z areas of the variegated kernels of table lé~a, all of the
C bz areas were wx; none showed Wx = wx variegation. In the cross to
the ¢ sh 33 wx ds ac female plants, the Ds mutation in the ¢C $h 4x
kernels resulted in o sh wx sectors, No #x - wx variesation was
present in the © areas and, as stated, all the c areas were wx, Again,
large wx sectors were not appearing in the C areas, This type of
variegation would be expected if only one Ds locus were present and
if its position were to the right of the proximal duplicated segment.
It should be noted that none of the © Sh bz wx or C Sh Bz wx kernels in
table l6-a was © = c variegatec. None should be variegated for these
kernels should have a normal chromosome 9 with no 3s locus. These
¢ Sh bz wx and C Sh Bg wx chromosomes arose from a crossover in
regions 1 and 2, resvectively. It should be noted that no ¢ sh bz dx
kernels were produced, These would appear only if a rollen grain
carried a double crossepver chromatid (regions 2 and 3), Such a double
cross-over chromatid should appear relatively infreocuently. No such

chromatid was represented on this ear.
Table 16-4

C ds Sh Bz 4x Wx Bz Sh Ds
Cshbzwxdsac? x §-43-S0 Sa ix Wz bz Shoe, AG Aco d

43563<3 4625L-1

 

a

C Sh Ba Wx /C BaeC ba, Shesh C Sh Bz wx C Sh ba wx C sh bz fx C sh bz wx

 

Wx=wx non-varie-
fated p
1st 125 74 10 o 188

 

* Several have a few wx spots.
Supplement to table lé<-a

a

3

C ads Sh | oe bug Wx Bz Sh Ds

aes,

Cds sh bz wx ds >

Non-crossovers C da Sh
C as sh
Region 1 C as ah
C€ da Sh
Region 2 C da sh
C de Sh
Region 3 C ds sh
C ds 3h

Summary:
Crossing over Region 1]
Region 2
Region 3

* Too high; probably includes some No Da or No Ao gametes due to

Ba
bz

bz

bz
Bz

bz
Bz

Wx Wx Bz Sh Ds

wx ds

Wx Wx Bz Sh Ds

Wx

Wx Wx Ba Sh Ds

wx ds

wx dix Bz Sh De

#x ds

4.4%
“32.
517

loss or transposition of Ds or Ao,

“ C BaeC bz Sh, Wx-wx

- © eh bz wx

= ¢ Bec bz Sh, W#xewx
= ¢ Sh bs wx

= ¢ BaeC bz, Sh, ¥x=wx

= ¢ Sh Bz wx

= ¢ Bz-C bz 3h, Wx=wx
~ € Sh Be Ax

128

10

74

13*
Table 16-b

We
c sh wx ds ac 2? x 46281L-]1 ¢

 

 

 

Cross GC Sh wx § Cwc, Shesh, cCShwx C sh dx C shwx Odds
non-varie- $$$ W#xewx
gated :
4347~4 x 46281-1 10 129 — 68 = eB | oa 46
4418F-2 x 4628L-1 8 50 360260 aL SR Colorless dx-wx;3h
A416F-2 x 46281-1 4 59 46 0 - 3
Totals 22 218 160 = 3* AB

 

* 1 has defective embryo; probably carries an abnormal chromosome 9.

™

at

J Feed
Atg ye v3

f ey ;
WK ve Fak D Tr Aes necl Ve Cac

~ ——_ | 3 ° ~ , é ol } - A
\ocukiad paren Cnbamerchey - Wet T Tee Dh [coh uy ar
4

}
4
Table 17a

C ds sh bz Ax Wx Bz Sh Ds” Ac ae
C sh bz wx ds ac & x C ds sh bz wx ds

 

 

 

46281L~2
Cross Cc Sh Bs Wx C Ba-C bz, 3shesh, C sh bz ax C sh bz wx
non-varie~ Wxowx hon variegated
gated (Ac ac ac) (Ac ac ac and (Ae ac ac and
{ac ac ao) ac ac ac) ac ac ac)
4361-16 x 4628L-2 59 59 li 255
4366-9 x 4628L-2 37 34 ll 245
Totals 96 93 22 500

 

Cross~over region

C da sh bz axt Wx Bz Sh Dsa&

 

ec ds sh bz wx Fe

Cross-overs: C ds sh bz wx dx Wx Bz Sh Ds® Duplication chromosome 9
. C ds sh bz 4x ds Normal chromosome 9 = 22

Normal chromosome class
"rossovers

522
4.2%

es of
Supplement to table 16=b

@ sh B2 wx ds ac ¢ x € ds Sh Bz Wx Wx Bz sh De? Ae Ae of
C ds sh bz wx
12

ty
C.Sh Wx Wx sh Dee
C sh wr dg

Non-crossoverg C Sh #x 4x sp De® “= Cec, Shesh, dxewx

C ah wx da = C bh wx £42
Region 2 C 8h ¥x ¥x Sh Dg2 “ Cea, Shesh, dxawx

C Sh wx ag | * C Sh wx 150
Region 2 C sh wx wx Sh De® = C«o, Sheesh, dx=wx

C Sh Wx ag - C Sh Wx g2*
Regions 1 & p C Sh wx Wx 3h De® = Cee, Shesh, dxewx

C gh 4x dg = C¢ sh ax 3

* Teo high; probably includes No Ds, or No Ac ¢ gametes due to loss
or transposition of Ds or Aa,

Summary of crossing over; Region 1; 36.7%
Region 2 ; 6%

0.72% (with no interference
Would exnect 2.27%)

Doubles

=e
wD So

Plant 4628L=2 was similar to plants 4628Ke] and K-2 in the genie
and chromosomal constitutions of ite chromosomes 9, It was heterozygous
for Ac (Ac ac). In crosses to © sh bz wx ds ac female plants, half
of the © Sh Bg Wx carrying kernels were ° Bz - © ba, Sh = sh, wx + wx
variegated (the Ac ac ac kernels) and half were none-variegated (the
ac ac ac kernels), table 17a, Again, in this cross, a small
percentage of the C sh bz kernels were Wx (4.2%) and again, none of
these kernels were Wx « wx variegated. The reason for this has been
stated previously in the description of similar crosses involving
4628K-1 and Ke2,

dhen plant 46281~2 was crossed to ac sh Bz wx ds ac female
plant, the expected types of kernels appeared, table 1?-b. Half of
the C Sh Wx kernels were non-variegated and half were C ~ c, Sh sh,
ax = wx variegated, In the variegated kernels, all c areas were wx
and no large wx sectors were regularly appearing in the C areas, The
13 ¢ sh Wx kernels (3,9% of the sh class) were non-variegated, To
repeat, since they carry a normal chromosome 9 with no Ds locus, no
variegation should appear,

Plant 4628L~2 was crossed to a c sh x, Ac Ac female plant, The
kernela resulting from this cross are indicated in table 17-c, No
obvious C - o variegation could be observed in approximtely half
of the C Sh kernels, These are probably the Ae Ao Ac kernels, The
kernels showing C « c variegation had a pattern of Ds mtations
characteristic of Ac Ac ac constitutions, «again, it may be noted that
no C ~ c variegation was present in the ¢ sh class of kernels,

No variegation is expected,
Table 17 b

© sh wx dsp ac ¢ x 46281-2 ¢

 

!

 

 

 

Cross C Shix | Cec, Shesh, 4x-wx C sh Wx C sh wx
non-varie~ non-varie~
ted __ gated
AO AG and ac Ac and ao
4347-24 x 46281-2 39 35 . 13 31?

 

Cross-over recion

 

 

 

C ds sh Wx ix Sh Ds _
C de sh wr 48 gw
Cross-over:
Duplication chromosome 9
C ds eh wx Wx Sh De
a
Normal chromosome 9
C ds sh ux _ = 13

 

Total kernels = 404

Normal chromosome class : 330

crossovers : 3.9%
Table 17-0

co ah Wx

¢ o 8.1 Wx

Ao Ae @ x 46281-2 ¢
Ae ac

 

‘Duplication chromosome from d |

Normal chromosome

 

 

 

 

CO sh Wx | Ceo,Sh-sh, ix | Cc sh dx
Not obviously ' nonevariegated
variegated (Ac Ac Aco and
{Ac Ae Ac) (Ac Ac ac) Ao Ac ac)
4365-20 x 46201<2 65 59" 219

 

* 86 kernels are speckled with o; late Ds mutation

1 Kernel has an Ao ae ac type of C — co variegation, Yoo, og aif on
Table 18

on 2b
Plants arising from various kernels frem self-pollinatien,of plant 4306 (see Table 3).
Chromosomal and genic constitutions of plants of culture 4628; sub-sultures C to L.
Dup. * Duplication chromosome 9. Nor. = Normal chromosome 9

Appearance of

 

 

Aotivator Table or page
Plant Chromosome 9 constitution constitution feference peers from which
Dup. I Ds? 3h Bz Wx Wx Bz Sh Ds*
4628C-9 pup. I Del Sh Be Na Wx Be Sh Det Ac Ac Table 7 I Sh 4x
1s ax 3 3 2
m pezo Dupe I Ds” Sh Bz 4x 4x Bz Sh De Ac ac Table 8 I-¢ Bz-C bz,Sh-sh,
Nor. C ds sh bz wx ds dxewx
° si s dx Wx Bz S 2
* Dell Dup. I De® Sh Ba tx Wx Be Sb Ds Ae ac Table 8 I-C Ba-C bz,Shesh,
Nor. C &s sh bz wx ds 4x=wx
1 sh?
"Fe 1 Non . oe = ve a Ao Ae Table 9 I 3h wx
*,*.,
s Fe 2 Nor. I ds Sh Bz wx ds ? Table 10 (see page's) I Sh wx

Nor. C ds sh bz wx ds

-

Nor. I Ds! Sh Bz wx ds -
" Ge 1 Nor. C ds sh bz wx ds Ac ac Table 11 IeC Ba-C bz,Sh-sh,wx

©

eH

Dsl sh Bz wx ds ac ac Table 11 I-c Bz-C bz,Sh-sh,wx

Nor.

oo

bet

la
Ds+ Sh Bz wx ds AG ac Table 11 I-C Ba-C bz,Sh<sh,wx
ds sh bz wx ds

4 fee 3 Nor.
Nor.

3
4628H=1
"Hee
" Jol
" Ine
" Kel
" Kee
"  Lel
" Lek

Nor.
Nor.

Nor.
\Nor.

Nor.
Nor.

Nor.
Nor.

Dup.
Nor.

Dup.
Nor.

Nor.

Dup.
Nor,

G

Q

Dal
ds

det
ds

sh b3 WX neterofertilization

Table 18 continued

Sh Bs wx
sh bz wx

3h Bs wx.
sh bz wx /

sh bz wx

Dst sh bz wx de

ds

ds
ds

ds
ds

ds
ds

as
ds

sh bz wx ds

sh
ah

sh
sh

3h
sh

sh
sh

bz
bz

bz
bz

Be
bz

bz
bz

Nx
wx

Ax
Wx
Wx
wx

Wx

Wx Bz Sh Da?
ds

Wx Bg Sh Ds®
ds

ax Bz 3h Ds®
ds

dx Be Sh Ds2
ds

Ac ac

Ac ac

Not tested

ac ac

Ae Ac

ac ac

Ac AC

ac ac

Table

Table

Table

Table

Table

Table

12

See page 1%

See page

13

14

15

16

17

I-C Bs-c bz,Sh-sh,wx

IeC Bz-C bz,Sh-sh,wx

I sh wx

I seh wx

C Sh Ba ax

C Sh Bz ax

C Ba-C bz,Sh-sh,
dx-wx

C Bz-C bz, Shesh,
AX=WxX

 
aPhea

5. Considerationf of the events responsible for the transposition

of the Ds locus

The genetic analyses of the plants in culture 4628 has allowed a
reconstruction to be made of the genic and morphologieal constitution
of the chromosome 9 in the mother plant (4306), All the tested plants,
except 4628C~9, had one normal chromosome 9 carrying © sh bz wx, The
constitution of the homologous chromosome 9 in some of the sub-cultures_
(D, &, G and H) could be anticipated from the type of variegation
appearing on the kernels from which these plants arose, ‘The constitu-
tions of plants in sub-cultures F and I could likewise be anticipated
within the seope of several simple alternatives, The Dlants in sube
cultures K and L could have a number of different chromosomal and
genic constitutions, To determine the exact constitutions of each
Plant would require the tests that have been desoribed above,

Figure 1 has been constructed to make this anticipation readily
appreciated, Subecultures D and F probably received a non-crossover
Duplieation chromosome 9. Plant 4628I—=2 and L~] received chromosomes
arising from a crossover in region 2 in the mother Dlant. The crossover
chromatid in 4628-2 is the reciprocal of the one present in 4628L-1,
Region 4 has the longest unit crossover distunce, A crossover in this
region would cive rise to a morphologically normal chromosome 9 with
I Dat Sh Bz wx and a Duplication chromosome 9 with C ds sh bz jx 4x 32 Sh
Ds’. These two classes of reciprocal crossover chromatids should be the
most. frecuent of all of the crossover Classes of chromatids and there~
fore they should be the most frequent ones recovered in a self
pollination or an outcress, Although the numbers ars few, the analysis
of the genic constitutions of the chromosomes 9 in the Plants in sube

cultures *, G and FH and in sub-cultures K and L are in acreement with

this expectation,
ys a j

*

Figure 1

 

 

‘ \ a
Te Sng an Any be ci Ds
ee ree _— 7 - i _ . L fuse
Seppe 7 re
a: AY :
(tae we he A hey 1 ie
| a
Po
| . 4 5

Cross-over chromatids recovered from plant 4306,

I Dat sh bz wx; Normal chromosome 9$ Plant 4628I-2

Region 2
C de 3h Bz 4x Wx Sh De®; Duplication chromosome 9) Plant 4626L=1
I De+ Sh Bs wx; Normal chromosome 91 Plants 4628%=1, Gel, Gaz,
Region 4 GeS, Hel, He?

I ds sh bz «x Wx Bz Sh De®; Duplication chromosome 0,
Plants 4626K~1, Kef£, Lek,
#2 Baw

The order of the genes in the proximal segment has been given
little consideration in the preceding discussion, It is necessary
to indicate, therefore, why this order is required and why the
particular marked loci have been placed in this segment, The analysis
of the synaptic configurations of a normal chromosome 9 and the Dupli-
cation chromosome 9 in the heterozygous plants (pages }) and the
analyses of the chromosomal and genic constitutions of the recovered
crossover chromatids along with their frequencies, has indicated the
composition and order of genes in the distal of the two duplicated
segments, It is composed of a unit of the normal short arm of
chromosome 9 that begins just to the right of the I locus and extends
to a locus acproximately 4 units to the right of dx, It is pregent
in the Duplication chromosome 9 in the normal order, as these studies
have shown, A Ds locus is present at the Junction of this unit with
the distal third of the short arm, In other words, the Duplication
chromosome 9 has a normal gemic and chromosomal comoosition from the
end of the short arm to a position approximately 4 erossover units
beyond ix with the exception, however, that a Ds locus is present just
to the right of the I locus,

The proximal duplicated segment must contain Sh, Ba and Wx, The
presence of Wx in this segment is indicated by the crosses of 4628K=1,
Ke2 and Ie2 to C sh bz wx female vlants, If no Wx locus were present
in this segment of if wx were present, one should obtain some C Sh Bz wx
kernels and those having Ae should be © Bz «= C bz variegated, They
should appear in approximately 4% of the C Sh Bz class for they would

be the reciprocals of the Cc sh bz Wx kernels?
“26

o if & .
¢ wt My Wy %

 

br} Qrymerut 7
vn snus eee <t> -_— =
ae Lo
C ak
, ca
AS geen .
Hy guuol chun

Such kernels would not appear, however, if a Wx locus were carried by
the proximal duplicated segment, Such kernels did not appear in the
crosses. It could be concluded, therefore, that a #x locus must be
present in this segment.

Sh and Bz loci must likewise be present in this serment,. The
evidence for this is apparent from several considerations, It is most
obvious, of course, in the phenotypes produced by the Duplication
chromosome 9 in plants 4628K«1, K-2 and L-2, It is the Sh and Bz loel
in this proximal segment that accounts for the Sh and Ba phenotypes that
appear in the kernels from which each of these plants arose and in the
kernels having the Duplication chromosome 9 in crosses of these plants
to sh b2 planta,

Neither I nor C can be present in the proximal duplicated
segment, The absence of a C locus in this segment was considered on
page 4 . The absence of an I locus in this segment is apparent from the
phenotynes that result from a Dat mutation in an 1 Dat Sh Bz Wx Wx Sh Bz
pe* / c sh bz wx / © sh be wx, Ac ac ac kernel, A Dat mutation deletes the
I locus distal to Dat. The resulting vhenotyve is C. Again, if I were
present in this segment a Duplication chromosome 9 with the constitu-
tions shown to be present in sub-cultures 4628 K and L would not be
recovered, These chromosomes have no I locus in the proximal segment.

Neither an I locus, nor a C locus, therefore, is present in the proximal

s8epment,
27a

All of these considerations point towards the exact, composition of
the two segments with regard to the loci they carry, The position of
breakage that could give rise to such serments is also indicated, The
distel segment extends from a position just to the right of I (demarked
by the inserted Det locus) to a position 3 or 4 crossover units to the
right of the 4x locus in this seement. Crossing over between a normal
chromosome 9 and the Duplication chromosome 9 ia normal in kind and

relative frequency within this distal segment, as the tables have

shown, The crogsover unit distance between this distal ‘x loous
ang the junction with the proximal sepment in the plents heterozygous

for the Duplication chromosome 9 is the same as the crossover unit
distance between Bx and Ds-standurd in plants with two normal chromo-

somes 9, A summary of the cross over percentages in this region,

 

 

that oecurred in plants 4626K-1, e2 and le2 where it could be
determined, is given in table 19, The junction of the two segments is
marked by the position that Dsestandard oceunies in a normal I Sh Bg wx
Os chromosome, aAs shown in tables 1 and 2, the chromosome 9 in plant
4108¢81 that carried I Sh Bz Wx and De, was normal in ite senetic
behavior and had Ds at the standard location. The presence of only two
recognizable odd gametes was observed in the crosses of this plant.

One of these had the duplication that arose from an aberration ocourring
within this I Sh Bz #x Ds chromosome, In this Duplication chromosome 9,
the »roximal segment has the same genes within it as the distal segment,
This indicates that chromosome breakage occurred in a cell of the

parent plant (4108C+]) at the Ds locus and also at a position just

to the right of the I locus. This was followed by fusions of broken
encs that at the same time included a transposition of a Ds locus

between two of these ends, X3efore this event may be reconstructed,
Table 19

Summary ef table of per_cent crossing over between the distal ix

locus and the end of the distal duplicated segment based on the

recovered normal chromosomes 9 in crosses of plants 4628K-1,
4628K-2 and 4628L~2

Cds sh bz ¥x wx Be Sh De®

 

 

 

* 2 --
¢ ds sh bz wx} ae
“ON .
crossing over region
Cross GC sh wx Oo sh wx Percent

crossing over

 

 

4362C<3 x 4626K~) 323 8 2.4
4365-1 x 4628K~) 150 1 0.66
4561-11 x 4628K~2 132 4 2.9
4349-6 x 4628K~2 214 3 1.4
4462C=2 x 4628K=2 215 13 5.7
4361-16 x 4626L<2 255 ll 4,1
4566-9 x 46268L<2 245 ll 4.3
4347-24 x 4626L<2 317 13 3.9
Totals 1849 64 3.5

 

Total kernels: 1915
~28<

it is necessary to inquire into the order of the genes in the proximal
segment.

The order of genes in the proximal segment has been determined from
two general types of evidence: first, the type of variegation patterns
in the kernels having the Duplication chromosome 9 and secondly, the
tyoes of chromatids that plants heterozygous for the Duplication have
produced, The order could be (1) I pal sh Bz dx Sh Bz ax Da® or
(2) I Det Sh Be Wx dx Bz Sh Ds", If (1) were correct, it would be
difficult to explain how the large wx areas could arise that frequently
appear in the C Ba sectors in the I - ¢ Be ~- C ba, Sh «= sh, ix = wx
variecated kernels of tables Yea and 8, If the second of the two genic
orders was present, just such wx regions should appear because the
vreakage~fusionebridge cycles that are initiated by pat mutations
should often result in deletions of the two #x loci from some cells
while retaining the proximal 32 locus. In the crosses indicated, the
resulting cells would be C Bz wx. If order (1) were present, the C Bz
sectors that are variegated should have some C bz areas within them
that are Wx = wx variegated, As stated earlier, no such C b2 areas are
present. All of the C bz areas are wx, If order (2) were present, all
the ¢ bz areas within the C 32 sectors should be wx for the #x loci
should be lost from some cells by the breakare-fusion-bridge mechanism
before the proximal Bz locus is lost. In other words, 3z will not be
lost before the Wx loci are lost, In the crosses of plants 4628 Kel,
K-2£ and Le2 to © sh bz wx plants, no large wx areas appeared in the J 32
sectors of the variegated kernels and none are expected as thers is no
Ds locus to the left of Ds* that, ny mtation, could initiate a
dicentric chromatid having Bz and 4x in the region between the two
centromeres, These several observations, then, strongly support the

given inverted order of the genes in the proximal segment,
Figure 2

Types of chromatids that should be produced by crossing over with order of genes (1) and (2)
in Buplication chromosome 9

 

 

 

 

 

Type (1) order Type (2) order
A. Synapsis of distal segment of Duplication Ae Synapsis of distal segment of Duplication
chromosome 9 with homologous segment in chromosome 9 with homologous segment in
the normal chromosome 9 normal chromosome 9
tay , Single crossover chromatids Single erossover chromatids
Vy Yo : ‘ Ape
TpchRg © wet shy wep” TOS By we We . Be Shh
a i . seine eeagpene : pete en ve en oe ee . . ate meen maestro nee crt } ~-Or- oe
C & ab, Ly by - an - deadn by mt og i e ;
ON
Region 1 : Region 1
I ds sh bz wx ds Normal chromosome I ds sh bz wx ds Normal chromosome
C Del sh Bz ax Sh Bz Wx Ds Duplication c Dsl Sh 32 Wx Wx Bz Sh Ds2 Duplication
chromosome

chromos ome
2

Det sh bz wx ds
ds Sh Be Ax Sh Bz

Del Sh bz wx ds
ads sh Bz 4x Sh Bz

Dst 3h Bz wx ds

ds sh bz ix Sh Bz

Dsi Sh Bz 4x as

ds sh bz wx Sh Bz

Figure 2 continued

Region 2

Normal chromosome

ix De® Duplication
chromosone

Region 3
Normal chromosome
Wx Dae Duvlication
chromosome

Region 4
Normal chromosome
ux Bse Juplication
chromosome

Region 5
Normal chromosome
Wx Ds® Duplication

chromosome

QO

Lo}

Region 2

pst sh bz wx ds
ds Sh Bz #x Wx Be Sh Ds®

Region 3
Dsl Sh bz wx ds

ds sh Bz ¥x 4x Bz Sh Ds*

Region 4
Del sh Bz wx ds
a@s sh bz dx Wx Bz Sh Ds®

Region 5

Det Sh Bz dx ds

ds sh b2 wx sx Bz Sh Ds”

Normal chromosome

Duplication
chromosome

Normal chromosome

Mplication
ehromo some

Normal chromosome

Duplication
chromosome

Normal chromosome

Duviteation
chromosome
Figure £ continued

 

B, Synapsis of proximal segment B. Segment of proximal segment
of Duplication chromosome 9 of Duplication chromosome 9
with homolagous segment in with homologous segment in
Normal chromosome 9 Normal chromosome 9
aa S om . ’ . vL : y, + !
EWR, PR cafe ee TeisR, Wi we tty
ee - ade . 7 : + met carter niet atm ane ES cn enameet Gene me stevatnee on <> dec a ne cee mee ne “St ye . a ee eee
nD Glen * ~ OQ
Cdn ah bs hy oo de des ee
Lo . Lo m we i,
. . a
Single crossovers All single crossovers would give a
dicentric chromosome and an acentric
Region 1 fragment. The dicentric chromosoxe
1 would be deficient for the terminal
I Ds” Sh Bz Wx sh bz wx ds Duplication third of the short arm.
chromosome
C ds Sh Bz Wx Da® Normal chromosome
Region 2
I Dsl Sh Bz vx Sh bz wx ds Duplication
chromosome
C ds sh Bz Wx Ds* Normal chromosome
Region 3
I Dsl Sh Bz Wx Sh Bz wx ds Duplication
chromosome
C ds sh bz ax Ds” Normal chromosome

region 4

I Dal Sh Bz ix Sh Bz vx ds Duplication
chromosome

C ds sh bz wx Ds@ Normal chromosome
~o29—

That an inverted order is present is again supported by the types
of crossover chromatids that could appear if type (1) organization were
present but would not appear if tyne (2) organization had been present
in plant 4306 or in plants 4628D-10 and Dell (table 8), Figure 2
illustrates the tynes of crossover chromatid that could be anticipated
from cenic orders (1) and (2) above, Homologous synapsis of the normal
chromosome 9 with the distal seguent would give phenotynically similar
crossover chromatids in the two cases, * Romologous synansis of the
normal chromosome 9 with the proximal segment, if order (1) were
present, could give rise to crossover chromatids havins the constitu-
tions shown in 3 of figure 2, The crossover c.romatids that should
arise from this association have not appeared. If order (2) were
correct, such crossover chromatids would not appear, From this
negative evidence, order (2) is again indioated,

It 1s possible, now, to reconstruct the events thit zave rise to
this Duplication chromosome 9 with a transposed %s locus, Three
assumptions regarding these events are recuired., (1) «a Ds mutation
occurred at its usual time--late in the development of the sporonhytic
tissues--in a cell of plant 4108C-1, The chromosome in which this Ds
mutation occurred was normal in morphology and carried I Sh Bz dx and Ds
in its standard location, The Ds mutation resulted in breakage of the
two sister chromatids at the position of the Ds locus in each chromatid.
Evidence that a Da mutation brings about breaks in sister chromatids at
the locus of Ds is well established, This assumption is therefore
legitimate, (2) The Ds mutation not only caused breaks to occur at the
position of the Ds locus but resulted in the release of a submicroscople
chromatin segment that carries a Da locus, This released segment
carrying Ds has unsaturated broken ends. It could be lost from the

chromosome complement if fusion with some other broken ends did not
~30-

occur. Loss of the Ds locus as a consequence of Ds mutations has been
considered in detail elsewhere (see report on ceml mutations, January,
1949), The manner of this loss may be suggested from cases such as the
one being described, (3) At the same time that the events described
in (1) and (2) occurred, a spontancous chromogome break ocourred just to
the right of the I locus in this chromosome, Both sister chromatids
were broken at the same locus, “vidence for frequent spontaneous
breaks in aaize is sood (MoClintock, unpublished), This assumption,
therefore, is legitimately taken, ‘hese three events would cive a
series of broken ends as shown in a, figure 3, “usion of broken
ends could readily occur to give rise to the configuration shown
in B, figure 3, “he resulting chromatids are diasrammed in C, figure
5. « Dunlication chromosome 9, with an inverted order of genes in the
proximal duplicated segment and having a transposed Ds locus just
to the right of the I locus is now formed,

On the basis of the depicted rode of origin of the Duplication
chromosome 9, it must be assumed that the two Ds loci are daughter
DS locl derived from reduplication of a mother 3s locus, The -utae-
tional behavior of the two 2s loci in this chromosome are not alike.
More dicentric chromatid-forming -utations oceur at Det than at
De®, The states of the two Ds loci definitely differ from one
another, This is particularly upoarent when these two loci are
senarated by crossing over and the crossover chromatids isolated,
Vhen, the ~utational behavior of Dsl may be directly compared with that
of Os", Either a change in state occurred in one or both of the Des
loci during one of the events that gave rise to the duplication and
the transposition; or 2 chanze in state in one or both Ds loct took
place subsequent to this event, There is no evidence for any vesition

effect associated with the altered genic associations of the to Ds loci,
Figure 3
A.

Position of chromosome breaks

 

B.

Fusion of broken ends

 
Figure 3 oO,

Resulting chromatids

 

IW shBy We Wa RQ ch Co
T .
ne fp

 
aot le

Changes in state of these two separated Ds loci are occurring indepen-
dently of their positions as no few of the variegated kernels have
shown.

Again, it should be emphasized that the transposition of the Ds
locus has not introduced any visible alteration in the appearance of the
chromosome in the region of the transposition. Neither has its
insertion affected the crossing over in the I to Sh region, To
refresh this evidence, a summary of this crossing over in the crosses
of clants in sub-cultures 4628 7, G and 'l are given in table 20,

These observed crossover percentazcs are similar to those observed when
no Ds locus is present, The inecrted segment carrying Ds must be very
ninute--obviously submicroscopic in size,

The analysis of this case of transposition of Ds has indicated the
method for selecting those relatively rare kernels with newly arising
transposed Ds loci, In the crosses of I Sh Bz Vx Dseestandard to
C sh ba wx ds ao plants, the kernels with aberrant variegation of cuite
svecific tynes may be selected, It is possible, by this method, to
detect those chromosomes having Ds inserted to the left of I,
between I and Bz and between 5z and Wx. aA number of such kernels have
been selected and an analysis of the transposition of th Ds locus is
being conducted, Evidence from these other cases should be well
advanced by the time the greenhouse crop is collected and certeinly by

the time the summer crop is harvested,
Table 20

Summary of crossing over between I and 3h in plants 4626F-1, 4628G-1,
G2 and Ge3, and vlant 4628H-}

Normal chromosome 9 I Dal gh

 

Normal chromosome 9 C ds sh

 

 

Table reference “ot Kernels arorscover cron eco ae
chromatids
Table 9, 4628F~<] 564 28 4.9
Table ll-a, 4628 1461 85 5.5
Table ll-b, 4628b 1243 49 349
Table 12, 4626H-1 525 19 3.6

 

Totals 3793 181 4.7

 
-~ 32 - transpOsed Ds 4628
ps Case I Duplication rode

Appendices to: Fane} dus
Transposition of the Ds locus, April, 1949. Vas?

In the previous account the Case I transposition of the Ds locus,
april,1949. the origin and behavior of this case of transposition was
analysed in considerable detail. Continued examination of this case
has resulted in corfirmation of the conclusions given in the earlier
report. In this supplement, the confirmatory evidence will be given
in the form of appendices. The table numbering will follow sequentially
from the previous resort.

Appendix 1

In the cross given in table 7-c, an Ac ac, C sh bz wx ds female
plant was crossed by plant 4628C-9. This latter plant was homozygous
for the duplication chromosome 9. Both chromosomes carried
I Dst Sh Bz wx Wx Bg Sh Ds*, The plant had one Ac locus. A number of
kernels appeared on the ear that showed only a few specks of © color
(column 1, table 7-c). It could be anticipated that these kernels had
3 Ac loci in their endosperm cells, two contributed by the female parent
and one by the male parent. If the Ac loci in both plants were located
in allelic positions, the plants arising from these kernels should be
Ac Ac. Some of these lightly speckled kernels were selected from
the cross of 4462€-11 x 4628C0-9 (Table 7-C) and plants grown from
them in the summer of 1949 under culture number 4876A. these plants
were crossed to: (1) C sh bz wx, ds ac plants (Tables 2l-a and 21-b),
(2) by C sh bz wx, ds ac plants (Table 22), and (3) to ¢ sh Bz wx,
ds ac plants (table 2l-c).

In cross (1) above, the types of male gametes, with respect to

chromosome 9 morphology and genic constitution, should be the same as

those given in the supplement to Table 8. It was hoped, however,

that two allelic Ac loci would be present in the tested plants so that

Bel
- 33 -

a more direct analysis of the chromosome and genic constitutions of
the resuiting progeny would be available. The four tested plants
in Table 21-a had two Ac loci. Unfortunately, however, these two loci
did not occupy allelic positions, as the results given in this table
indicate. The classes of kernels and their frequencies are those
expected if these four tested plants had two non-linked, non-allelic
Ac loci. This is shown in the supplement to Table 2l-—a. It must
be concluded, therefore, that the Ac locus in the two parent plants
occuppied different positions in the chromosomal complement. In
all other respects, however, the results are the same as those
given by plants having the same chromosome and genic organizations
that were tested in the previous season, Table 8. Therefore, no
further description or analysis is required.

In one plant of culture 4876A, the Ac constitution of the
main stalk and the tiller differed. This is shown by the
frequencies of kernel types obtained when pollen from the main
stalk and pollen from the tiller were used in crosses to C sh bz wx,
ds ac plants, Table 21-b. The ratios of kernel types obtained
when pollen of the main stalk was used indicate that only ong Ac
locus was present. The pollen from the tiller gave ratios of
kernel ty;es that indicate the presence of two non-linked, non-
allelic Ac loci. It cannot be decided from these tests whether or
not the tiller gained an Ac locus or whether or not the main stalk
lost an Ac locus. Hither event could account for the observed
difference in the two parts of the plant.

Two of the plants entered in Table 2l-a were crossed to
ec sh Bz wx, ds ac plants. The types of kernels appearing on the
resulting ears are given in Table 2l-c. As the supplement to

Table 2l-c indicates, the types of kernels and the ratios
- 34 =

observed are those expected from the stated constitution of these

plants.
In Table 7-c, one aberrant kernel was recorded. This kernel
had the phenotype C Sh Bz Wx and was non-variegated. Such a kernel

was not expected to appear following the cross given in Table 7-c.

A plant was grown from this kernel. It was crossed to ac sh Bz wx,
ds ac plant. There were 345 kernels on the resulting ear. 51 were

C Sh Wx, non-variegated; 2 were C sh Wx, non-variegated and 292 were

C sh wx, non-viriegated. When the plant was crossed to a C sh be wx,
ds ac plant, the resulting ear showed 27 C Sh Bz Wx non-vriegated
kernels, 23 C Bz + C bz, Sh, Wxewx (bz areas wx) kernels, 2 C sh bz Wx
non-v:riegated kernels and 116 C sh bz wx kernels. The plant was
likewise self-polliniuted. The resulting ear showed 229 C Sh Bz Wx

(a number were variegated) one C sh bz Wx and 156 C sh bz wx kernels.
If the tested plant had the constitution Duplication C sh bz Wx Wx

Bz Sh Ds/C sh bz wx, ac ac, just such ratios following the given
cross would be obtained (see Tables 15-b, 15-c and Tables

It is suspected that contamination was responsible for the appearznce
of the aberrant kernel in Table 7-c,or that the pollen grain that

gave rise to this kernel had a deficiency in the distal segment that
indluded: the I,Ds, Sh,and Bz loci. Only further tests could
distinguish between these two possibilities.

In the April 1949 report, no evidence was presented for the
trinsmission of the duplication chromosome through the egg parent.
Plants heterozygous for a normal and a duplication chromosome 9
give reduced transmission frequencies of the du: lication chromosome
through the pollen. The ratios of tee C Sh Bz Wx Kernels to tke
C sh bz Wx and C sh bz wx kernels in the crosses of C sh bz wx by

yt 4
Duplication C sh bz Wx Wx Bz Sh Ds/normal chromosome 9, C sh bz wx
- 35 -

indicate the transmission frequencies through the pollen of the

dup.ication chromosome 9. Compilation of the data from Tables
give a ratio of

Duplication chromosomes 9 to normal chromosomes 9. such a

reduction in transmission of the duplicated chromosome is likewise

1 sh Bz wx Wx Bz Sh Ds“/

evident when plants of the constitution I Ds

C sh bz wx are crossed to C sh bz wx. Because the crossing-over

between the distal Wx locus and the proximal segment is low, the

frequency of the Wx to we class gives the approximate frequencies

of transmission of the duplication and the normal chromosome. The

combined data from Tables 8, 2l-a, 21-b and 2l-c show 1694 Wx to

3331 wx kernels. In the reciprocal cross, no such reduction in

trinsmission of the duplication chromosome is expeeted. Four of

the plants entered in Table 21 were crossed reciprocally. The

results of these reciprocal crosses are given in Table 22,

Because of the presence of 4 Ac loci in the endosperms of many

of the kernels, it was not possible to make an accurate classification

for the presence or absence of Ac in all the kernels. In the table

a significant reduction in the Wx class is evident. This is

probably not related to a reduction in transmission of the duplication

chromosome, Rather, it is related to Ds mutations occurring

before meiosis that produced non-female transmissible deficiencies,
Data given in Tables 21 and 22 show that crossing-over

between the normal chromosome and the distal duplicated segment in the

Duplication chromosome 9 is relatively little affected by the

presence of the duplication. This would suggest that synapsis is

not seriously disturbed by the presence of the duplication; otherwise,

a considerable reduction in crossimg-over between I and Wx would be

evident.
-~ 36 -

Appendix 2

In the summer of 1948, plant 4628K-1 (Tables 14-a and 14+b)
having the constitution Dup. C sh bz Wx Wx Bz Sh Ds/C sh bz wx,
Ac/Ac, was crossed by plant 4628L-1 (Tables 16-a and 16-b) with
the constitution Dup. C Sh Bz Wx wx Bz Sh Ds/C sh bz wx, Ac Ac.
it was hoped that some of the plants arising from the C Sh Bz Wx

class of kernels on the resulting ear would be homozygous for the

duplication and for Ac. The ear was small and only a few kernels
of the desired type were available for testing. Six of these kernels

were planted in the summer of 1949 under culture number 4848 but only
4 of them germinated. The constitution of three of these plants
were exactly like the female parent plant (4628K-l1, Table 14) as
the results of reciprocal crosses with C sh bz wx, ds ac plants have
shown, Tables 23, 24, and 25,

One of the plants in culture 4898 (4898-2) had the constitution
Dup. C sh bz Wx Wx Bz Sh Ds/C Sh bz wx, Ac Ac. The duplication
chromosome must have been contributed by the female parent plant
whereas the normal chromosome with C Sh bz wx arose from a crossover
in region 1 of the male parent plant (see supplement to fable 1l6~a).
Reciprocal crosses of this plant with C sh bz wx, ds ac plants are
given in Tables 26-a and 26—b. The cross of this plant to a
ec sh Bz wx, ds ac plant gave the kernel types listed in Table 26-c.
Crossing-over between Sh and wx in this plant was very high in the
microsporocytes but a much lower frequency of recovered crossover
chromatids crime from the megasporocytes. such high rates of crossing
over in this segment of chromosome 9 have been encountered when two
normal chromosomes have been present. A reduced amount of
crossing-over in the megasporocytes as compzred with the microsporocytes

has likewise been observed in numerous tests.
-~ 37 -

Appendix 3.

In the crosses of C sh bz wx, ds ac plants by Ac ac plants

1 Sh Bz Wx Wx Bz Sh Ds*

having the Duplication chromosome 9 with I Ds
and a normal chromosome 9 with C sh bz wx, a number of distinctive
kernel types appeared (Table 8). The projected constitutiow of
these kernels are given in the supplement to Table 8. In order to
determine whether the projected constitutions were correct, some of
the kernels from the cross-over classes were selected from two of

the crosses, 4462C0-8 x 4628D-11, and 4363-17 x 4628D-11 (Table 8) and
grown in the summer of 1949 under culture numbers 4877 and 4878,
respectively. Two plants arising undexrxgukturexnumkers from the

I4+C BzsC bz, Shesh, wx kernels (48774), four plants arising from the
C BzsC bz, Shesh, Wxewx kernels (4877C) and the plants arising from
two C Sh bz wx kernels (4877E) in cross 4462C-8 x 4628D-11 were

tested for their chromosome 9 constitutions. In the cross

4883-17 x 4638 D-11 (Table 8), four plants arising from the C Bz-C bz,
Sh-sh, Wx-wx kernels (4878D)were tested for their chromosome 9
constitutions.

Table 29 gives the ratios of kernel types obtained when the two
plints ariwing from the I BzeC BzyC bz, Shash, wx kernels were crossed
by C sh bz wx, ds ac plants. The results are those anticipated from the
given constitions shown in the heading to this table. The plants
arising from the C Bz-C bz, Sh-sh, Wx-wx kernels should all have the
Duplication chromosome 9 but the genic constitution could be. several
types, as the supplement to Table 8 and Figure 2 illustrate.

Crossing over in regions 1 to 5 would give the following genic

constitutions in the duplication chromosome:
1 Sh Bz Wx wx Bz Sh Ds*

2

Region 1: Dup. © Ds

Region 2: Dup. © 8h Bz Wx Wx Bz Sh Ds
- 48 -

Region 3: Dup. © sh Bz Wx Wx Bz Sh Ds“

Region 4: Dup. C sh bz Wx Wx Bz Sh Ds°

Region 5: Dup. © sh bz wx Wx Bz Sh Ds“
Because crossing-over in region 4 is the highest, the majority
of the C Bz-C bz, Sh-sh, wx-wx kernels in the cross shown in Table 8
should give plants with the constitution: Dup. C sh bz Wx Wx Bz Sh Ds/
C sh bz wx, Ac ac. Of the 8 tested plants arising from such kernels,
were definitely Dup. © sh bz wx Wx Bz Sh Ds/C sh bz wx, Ac:ac
(Table 27, a and b), were Dup. C sh bz wx(or wx)Wx Bz Sh Ds/
C sh bz wx, Ac ac (Table 27-d). the tests of the latter plants were
inadequate for determinging the presence or absence of the distal
Wx locus. One plant, 4878D-1, had the constitution Yup. © sh Bz Wx
Wx Bz Sh Ds/ n-rmal chr. 9 C sh bz wx, Ac ac, as the results of the
cross of this plant by a C sh bz wx, ds ac plant indicate (Table 28).
fhe constitution of the duplication chromosome in this plant resulted
from a crossover in region 3 of the osrent plant.
In cross 4462C-8 x 4628D-11, Table 8, the 2 C Sh Bz wx kernels
could be expected to appear following a double crossover in regions
2 and 4 in the male parent. A normal chromatid carrying C0 Sh Bz wx
wo:ld result from such a double crossover. fhe plants arising from
these two C sh bz wx kernels were cros:ed by C sh bz wx, ds, ac ac
male plants. The resuits of this cross, Table 30, indicate tne
presence of two normal chromosomes 9 in each plant. No evidence of

a Ds locus in the © Sh Bz wx chromosome appeared in either case.
- 39 -

Appendix 4.

Table 14 gives the tyves of kernels a;pearing when a Duplication
C sh bz Wx Wx Bz Sh Ds/ Normal C sh bz wx, Ac Ac plant was crossed to
a C sh bz wx, ds ac plant. With regard to genic constitutions of
chromosomes 9, four types of gametes could be exvected to be
produced by the male parent. These are:

Non~crossover chromatids
(1) Dup. C sh bz Wx Wx Bz Sh Ds

(2) Normal C sh bz wx
Crossover Chromatids

(3) Dup. © sh bz wx Wx Bz Sh Ds

(4) Normal C sh bz Wx

The genic constitution of the chromosomes 9 of seven plants arising
from the C Bz-C bz, Sh-sh, Wx-wx kernels of Table 14-a were tested.

96 to 98 percent of the plants arising from these kernels should have
the constitution Dup. © 5h bz Wx Wx Bz Sh Ds/Normal C sh bz wx, Ac ac.
All seven tested plants had this constitution. Six plants were
crossed by C sh bz wx, ds ac plants, Tables 3l-a. All. plants

were crossed to C sh bz wx, ds ac plants, Table 31-b, One plant

was crossed to ac sh Bz wx, ds ac female plant, Table 3l-c.

Iwo kernels in Table 14-a were classified as possible C Sh bz wx
kernels. Such phenotypes were not expected in this cross. To
determine if Sh was: actually present, plants were grown from these
two kernels and self-pollinated. The self-pollinated ears showed only
C sh bz wx kernels. The Sh classification in Table 14-a is therefore
ervoneous, as anticipated. These two kernels should be moved to the

last column in Table 14-a,
~ 40 -

Appendix 5.

In Table 16-b, which gives the types of kernels appearing from
the crosses of c sh Bz wx, ds ac female plants by a Dup. C Sh Bz Wx
Wx Bz Sh Ds, Ac Ac plant, a single aberrant kernel was observed.
Two Cotrdess Omd SrQURd Sr or dnd Wey ioy Cam eset ay
This kernel was sown in the summer of 1949 and the plant arising from
the kernel was crossed to a C sh bz wx, ds ac plant and ac sh Bz wx,
ds ac plant. The tyes of kernels appearing on the two resulting eurs
indicated that this plant had the constitution I Sh Bz wx Ds Ac/
ec sh Bz wx ds ac. This constitution could not have been produced by

plant 4628L-1. The aberrant kernel in Table 16-b, therefore,

represents a pollen contamination and should be removed from this table.

Appendix 6.
In the crosses of C sh bz wx, ds ac plants by Dup. C sh bz Wx

Wx Bz Sh Ds/Normal C sh bz wx plants, Tables i4-a, 15-a and 15-c,

a few C sh bz wx kernels appeared. These were interpreted to arise
from crossovers as indicated in the supplements to these tables.
They should have two normal chromosoues 9. Plants from seven such
kernels were examined cytologicilly and all seven showed two
morphologically normal chromosomes 9. Two of the plants were self-
pollinated, Table 32-a, and two were crossed by C sh bz wx plants,
Table 32-b, and one was crossed to C sh bz wx, Table 32-c. The

expected ratios for Wx and wx were obtained.

Appendix 7.

In the cross of a c sh Bz wx, ds ac female plant by plant
4628L-2 which had the constitution Dup. © sh bz Wx Wx Bg Sh Ds/normal
C sh bz wx, Ac ac, an aberrant kernel appeared. This cross is not
given in the April 1949 report but is similar to that recorded in
Table 17=-b. This exceptional kernel was colorless and showed

Sh-sh, Wx-wx viriegation. A pant was grown from this kernel and
-~ Al -

crossed to a © sh bz wx, ds ac plant, Table 33-a, and by a C sh bz wx,
ds ac plant, Table 33-b. These tests showed that the plant carried a
Duplication chromosome 9 with © sh bz Wx Wx Bz Sh Ds. The phenotypic
appearance of the kernel from which this plant arose may have been
produced following an early spontaneous break that deleted the © locus
and initiated the breakage~fusion-bridge cycle that produced the

Sh-sh, Wx-wx vuriegation.

Appendix 8.

a ee

me bef Le

in order to obtiinaplants hiving a chromosome 9 with I Ds Sh Bz WX,

bendy: 3 “tay ‘OAS

‘Ae ac) 1 Bazo B2yC bz, Sh Wx kernels were selected from the ear of a
C Sh bz Wx/e sh bz Wx, ac ac female plant by plant 4628G-2 that was
I Ds Sh Bz wx/C sh bz wx, Ac ac. Two plants arising from such
kernels were crossed to © sh bz wx, ds ac female plants, Table 34.
The supplement to Table 34 indicates the types of kernels that should
appear following crossing-over. Crossing-over in region 3 gave the
desired constitution: I Ds Sh Bz wx. In these kernels, the C Bz
areas were viriegated for C bz and the majority of these latter areas
were WxX-wx viriegated. This is the expected viriegation pattern
that should be produced from dicentric formationas at the Ds locus,
immediately to the right of the I locus, which initiates breakage-
fusion-bridge cycles.

In these crosses, there were 6 C Bz-C bz, Sh-sh, wx kernels.
Such phenotypes could arise from crossovers in region l. It is
possible, however, to obtain such phenot; pes from I Ds Sh Bz wx
chromatids if a Ds event or events occurs early enough to eliminate
the I locus from all of the aleurone cells. This oceurs in a small

fraction of kernels when Ds mutations take place early in developm=nt.

Plants arisi:g from all 6 kernels would need to be tested to determine
-~ 42 .

whether or not arossing-over in region 1 or early loss of I following
Ds mutations were responsible for the appearance of the C Bz-U bz,

Sh-sh, wx phenotype.

Appendix 9.

The position of Ds in this cxse of transposition is definitely
between I and Sh. That it is close to the I locus has been apparent
from various crosses previously described. Calculitions of the
crossing-over between I and Ds (see prge 16) gave a percent ige of
0.74, This value was derived from the frequency of the © Bz-C bz
kernels in the crosses of C sh bz wx, ds ac female x I Ds Sh Bz wx/
C sh bz wx, Ac ac male (Table ll-a).

Tests for the presence of Ds in the C Bg chromosome of plants
arising from C Bzg= C bz kernels of tables lla and 12-b, and the
C-c kernels of table 11-b and 13-c, were conducted by growing plants
from these kernels and testing for the presence of Ds. Twelve

variegated
kernels were selected from,kernels, some from the crosses entered in
Tables ll-a, 12-b and 13-c, and some from crosses not recorded in the
April 1949 report. Two kernels that were doubtful variegutes were

likewise selected and the plants grown from them tested for Ds.

The various selections are given in the accompanying scheme, Scheme l.
(Insert Scheme 1, page 43)

+nformation concerning the origin of the selected kernels, the
nature of the variegation, the projected constitution of the derived
plant, and the culture number of the plant may be seen from the
arrangement in this scheme. The first 10 kernels in the shheme
were certain variegites. Nine germinated to give plants ind all nine
plants were tested for Ds. the last two kernels in the scheme were

uncertain variegates. The kernel that gave rise to plant 4885 had
- 43—

 

 

 

 

 

scheme 1 }
Cross Table ‘Phenotype of selected kernel frojected constitution of plant | 1949 Culture Number
Reference iL iurising from kernel
C sh bz wx, ds ac @ x 1 Ds Sh Bz wx he ae |
C ds sh bz wx .
o” |
4363-14 x 4628G-2 _ ll-a | C Bz-C bz, Sh-sh, wx ‘ 4884
446 2C-1a x 4628G-23 Not in April SCE eee
1949 report | " " " s sh bz wx 4887B
== ny
C sh bz wx 9 : .
= ¢ x I Ds Sh Bz wx , oy 1 C Ds Sh Bz wx
ec Sh bz Wx Suds ch be wx 7f ae ot " C Bz-C bz, Sh-sh, Wx Wds sh be wx 4883B
4358A-2 x 46286-2 : a C De S
| C~ca Sh Wx Ds ©h Bz wx
| eds Sh bz Wx _ 48850

Norm. C sh bz wx I Ds Sh Bz wx

Re. c oh Bz wx $ xX U ds sh bz wx ° ae

 

C Bz-C bz, Sh-sh, wx

 

 

 

 

 

C Ds “h Bz wx

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

a “Cds Sh bz wx HEGOC-1, 8900-2
4365-3 x 46 28H-1 12=b 7
| C+e, Sh, wx Norte =o ae 4890D-1, 4890D-2
o— —
c sh Bz wx, ds ac¢ x _I Ds Sh Bz wx Ae ae 1l-b \ ; C Ds Sh Bz wx
Cds 8h bz wx C-c, Sh-sh, wx @ ds sh Bz wx 4886 (no germination)
4347-22 x 46286-2 a
Re. c sh Bz Wx 9 x I Ds Sh Bz wx ac ac 11l-b | ‘ enlenw Norm, GC Ds Sh Bz wx
ds sh bz we gt “Cy MAWSNy NK Re. c ds sh Bz Wx 4882
4353-2 x 4628G-1
C sh bz wx, ds ac@ x I Ds Sh Bz wx Une area only of presence of Ds in
, Sas sh ba we 8¢ 20 7 ti-a | 0 Bz-C bz, Sh-sh; UC Sh Bz wx chromosome 4885
4684-3 x 4628G-3 wX uncertain
i ion
Re. c sh Bz Wxdg I Ds sh b2 wx ,. .. @ _ Possible C-c kernel Presence of Ds in
Norm.C Sy Bz wx Ds $ Cds sh bz wx “© 2¢ & L5-e but not certain 4891

4380A-8 x 4628I-2
Re Re

C sh bz wx chromosome
uncertain.

 
- 44 —

only an area of C Bz - C bz variegation. Tests for Ds were negative.
The variegated area in the kernel from which this plant arose may have
come from a spontaneous breakage in the chrorosome 9 carrying

C Sh Bz wx loci in one cell mid-way in development of the kernel.

The kernel that gave rise to plant 4891 was not certainly variegated.
A few specks that could hive been interpreted to be c in phenotype
appeared in this kernel. These c specks were suspected to be the
result of poor color development. It was thought wise to test for

Ds in the plant arising from this kernel. No Ds wis present in

plant 4891.

The nine plants arising from the ten certain variegated kernels
were tested by crossing to (1) C sh bg wx, ds ac, (2) ec sh Bz wx, ds ac,
and to (3) Rearranged chromosome 9 c sh Wx, ds ac female plants,
Tables 35 to 41.

The types of kernels appearing on the ears when plants 4883B

and C were crossed to C sh bz wx, ds ac plants are given in Table 35.

. vastalh

The presence of Ds to the left of Bz is indicated in the supplement

to Tuble 35. The variegated kernels may be used to obtain the crossover
frequencies between Ds and Bz. This gives a frequency of 5.8 percent
which is the amount expected if Ds were immediately to the right of the
C locus. Plant 4883B was crossed to ec sh Bz wx, ds ac female plunts
giving the kernel types shown in Table 36. A high percent of
crossing-over between Ds and wx is to be expected, giving a chromosome
with C Ds Sh Wx. When Ac is present, such a chromosome will give

C-c variegation in the indicated cross. The c areas should be Wx-wx
variegated because of the formation of dicéntric chromatids just to

the right of the C locus. The presence of Wx-wx variegation was

evident in all of the C-c kernels that carried Wx. The presence of

¥ Moos

i bw

Ds to the right of the © locus was indicated by the absence of
- 45 -—

twin areas with deep color in one area and colorless in its twin area.

Plant 4883C when crossed as a pollen purent to c sh Bz wx, ds ac
plants, gave the kernel phenotypes entered in Table 37. Crossing-over
between Ds and wx, based on the C-c kernels, was 29.4 percent.

The data entered in Tables 35, 36, and 37 are consistent in placing
the Ds locus immediately to the right of the C locus. It may be
concluded, therefore, that the kernel giving rise to plant 4883B

and plant 4883C wexe received a chromosome 9 that was derived from a
crossover between I and Ds that had occurred in the I Ds/C ds pollen
parent plunt (Table ll-a),

The projected constitution of plants 4884, 4887B, 4890C-1 and
4890C-2 was C Ds Sh Bz wx/C sh bz wx, Ac ac. These plunts were
crossed to plants that were c sh Bz wx, ds ac in constitution.

Plants 4884B, 4887B, and 4890C-1 had the expected genic constitution

as shown in Table 38. Plant 4890C-2, however, had the constitution

I Sh Bz wx/C sh bz wx. No Ds locus was evident. Heterofertilization
could account for the discrepancy in kernel and plant phenotypes but

the absence of Ds events in the I Sh chromosome of the slant arising from
this kernel suggests that a Ds event occurred in the division of the
sperm that eliminated Ds from one chromatid (sperm fusing with egg) and
initiated the breakage-fusion-bridge cycle in the sister chromatid

(sperm entering the endosperm nucleus). The data from the three

plants, entered in Table 38, allow the vosition of Ds in these plants

to be calculated. Only the variegated kernels may be used to

calculate the crossover percentage between Ds and Sh. The value
is 4.5 percent. This is the value expected if Ds is very close to
the C locus. +t is concluded that these three plants received a

chromosome 9 derived from a crossover between I and Ds that plved

Ds close to the © locus,
- 46 —

Plants 4890D-1 and D-2 were given the constitutions projected
in Scheme 1 (pzge 43): Normal chromosome 9 with CG Ds Sh Bz wx/
Rearranged chromosome 9 with c sh aed WX, AC ac. The projection for
plant 4882 was normal chromosome g°C Ds “h Bz wx/rearranged chromosae 9
with c Sh Bz wx, Ac ac. If each of these three plaints were crossed
to plants homozygous for c and sh and had no Ac, C toc variegated
kernels should appear AmMaNeXkheXkExNMEXS on the resulting ears.
Because of the presence of the rearranged chromosome 9 in these
three plants, the position of Ds in the homologous normal chromosome 9
could not be determined by crossover techniques. The presence of
a Ds locus in half of the C carrying kernels (those that have Ac)
is evident, however, in the crosses of these plants to plants
that were homozygous c sh Wx, ds ac, Table 39. Plants 4882 and
4890D-1 were crouged to a plant homozygous for ec sh wx, ds ac.
the results of this test are those expecte, Tables 40 and 41,

None of the data in Tables 35 to 41 gives evidence that allows

a determination of the closeness of the Ds locus to the C locus.

Tables 9, lla, 1ll-b, and 12-a, however, do show that this trans.osed
& : eae

t 5
eh oF ok PR

‘Ds is located very close, to the I locus. From these tables, the
estimited crossing-over between I and Ds is approximately 0.5.
the data in Table 34 project nanmmependeiaamiine of approximately 2 percent.
This value is much higher than the calculated values from the data in
any one of the other mentioned tables. However, several of the
six kernels showing a ¥ Bz + C bz phenotype (projected crossovers)

ama an 6E SEAR beeen: mio base hay Rt
in Table 54 may hae test the I aiid te the “consequence of a Ds
event that removed the I locus from one or both sperm nuclei.
*t will be necessary to test the constitutions of the chronosomes 9
in plants szrising from these kernels in order to determine the
reason for the@® phenotypic expression of each. The combined data

- a. ( prow ar?
indicate, however, that Ds lies to the right of 1 Gnd very close to it.
1 2
I Ds Sh Bz Wx Wx Bz Sh Ds

Table 2l-a

 

 

 

 

C sh b2 wx, ds ac 92 x Dup. Ac ac, ac ac o
Norm. cC sh bz wx
4805B-19 S805B 20 | S807-1 4807-8 (4808-25 4805- 27 |4804-10 !
Kernel type x x 'To otals
“8764-1 4876A+1 4876A+8 4876AW3 | 48763~4 4876A-4 4876A-5 |
I Sh Wx 23 37 7 7 33 22 22 151
I BZ - C BZ - C ba, Sh, 4x-wx 111 102 23 28 50 34 82 430
I Sh wx 10 15 "7 6 15 17 28 98
I BZ -C Bz-C bz, Sh wx 21 21 16 21 30 26 60 195
I bz - C bz, Sh wx 4 8 4 1 2 2 22
I sh wx not obv. var. 4 4 4 4°? 6 3 4 29
I bz =-C ba, sh wx 5 5 4 0 9 7 3 35
C Sh Bz Ws not obv, var. 15 13 4 7 20 9 13 81
C BZ = C bz, Sh, Wx-wx 26 37 4 14 17 15 19 132
C sh bz wx 201 149 60 76 158 129 254 1027
Odds 1c Sh Bz wx oO O 1c¢C Sh B21C Sh 1¢ Sh Bz 2C sh 6
wx Bz wx wx ba Wx
(var.?)
Totals: 421 391 133 165 341 265 488 2204

 

146 We: 140%my
Supplement to table 2l-ea
5

' oa 3) 64

—

 

C ds Sh bz wx |

Non-crossovers:

3
Dup. I Ds Sh Bz Wx Wx Bz Sh Ds
Sl
Norm. C ds sh bz wx Ac & ac
Region 1
Norm, I ds sh bz wx Ac & ac
_o
Dup. C Ds Sh Bz Wx Wx Bz Sh Ds
~i1
Region 2
3
Norm. I Ds sh bz wx i
1
28
Dup. C ds Sh Bz Wx Wx Bz Sh Ds@
1
Region 3
3
Norm. I Ds Sh bz wx
1
a)
Dup. C ds sh Bz Wx Wx Bz Sh Ds
Oy
Region 4
3
Norm. I Ds Sh Bz wx ~
1
8
Dup. C ds sh bz Wx Wx Sh Bz Ds
“1

Pen i ni eet rte a cnet ee

Ac

ac

Ac

ac

Ae
ac
Ac

ac

Ac
ac
Ac

ac

Ac
ac
Ae

ac

a "
Qa aA HH H Qa awn H

"
Qa Q HH He

2

Ds Sh Bz Wx . Wx Bz Sh Ds"

- © Ba - C bz Sh Wxewx = 4530

(with reg. 4 + doubles)

Sh Wx *" " " = 151

sh bz wx = 1027

sh wx

BZ = C bz Sh Wx-wx (bz areas

Wx-wx or wx)

Sh Bz Wx

bz - C bz sh wx = 35

sh wx

Bz - C bz Wx Wx-wx (bz areas
wx)

Sh Bz Wx

bz - C bz Sh wx = 22

Sh wx

Bz - C bz Sh Wx-wx (bz areas
wx }

Sh Bz Wx

BZ - C BZ - C bz Sh wx = 195

Sh wx

Bz - C bz Sh Wx-wx (bz areas
wx)

Sh Bz Wx
Supplement to table

2Zl-a (continued )

 

Region 5
_. 3 Ac = I Bz - C Bz Sh Wx-wx
Norm I Ds Sh BZ Wx =
~~~ Jo ae = I Sh Wx
_%3 Ac = © Bz - C bz Wh Wx-wx (bz areas
Dup. C ds sh bz wx Wx Bz Sh Ds wx)
“J ae = C Sh Bz Wx
Double crossovers
Regions 2 + 3
Norm. C ds Sh Bz wx Ac + ac = C Sh Bz wx = 4
. § Ac = I Bz - C bz Sh Wx-wx
Dup. I Ds sh bz Wx Wx Bz Sh Ds
“7 ac = I Sh Wx
Regions 4 + 5
Norm. C ds sh bz Wx Ac + ac = C sh bz Wx = 2
3 Ac = J Bz - C bz Sh Wx-wx
Dupe I Ds Sh Bz wx Wx Sh Bz Ds
lac = I Sh Wx
Supplement to table 2l-a (continued)

Normal chromatids

Non-cross-over 1027 C sh bz wx

Regions 1 + 2 62 I sh wx = I to Sh

Regions 3 + 4 315 I Sh wx = Sh to Wx

Regions 2 +» 3 = 4 C Sh Bz wx

Regions 4 + 5 2cC sh bz Wx

Totals 1410

% cross-overs region I to Sh = 4.6% (see Table 20 in Report
April, 1949 = 4,74)

% " wt n Sh to Wx =22,48%

Conclusion:
Presence of Duplication does not interfere with the normal

amount of crossing over in the region between I and Wx of the

distal segment.

 

Ratio of 2, 3 and 4 from variegated kernels with I
Region 2 = 33 I bz - C bz sh wx
Region 3 = 221 bz = C bz Sh wx

Region 4 = 195 I Bz - ¢ Bz - C bz Sh wx

Ratios 1.5:1: 9
Table 2l-b

 

 

 

 

C sh bz wx, ds ac 92 x Dup. I Dst Sh Bz Wx Wx Sh Ds” Ac ac ¢ (main)
Norm. € sh bz wx Ac he ae. (tiller) 3
Pollen from Pollen from
Kernel type main stalk tiller Totals
4806-7 4806-4
x x
4876A-2 4876A-2
I Sh Wx (not obv. var.) 41 32 73
I Ba ~cC Bz -C bz, Sh, Wx-wx 42 50 92
I Sh wx 37 28 65
I BZ -C bz -C bz, Sh wx 39 42 81
I sh wx (not obv. var.) 12 | 7 19
I bz - C bz, sh wx 9  & 13
I bz - C bz, Sh wx 4 3 : 7
C Sh Bz Wx 25 15 40
C Ba - C b2, Sh wx ol 29 60
C sh bz wx 184 105 289
Odds 1 Cc Sh Bz wx 10C Sh Bz wx 3
1c sh Bz wx
Totals 425 317 742

 

qos W ¥ + 537 pay
Table 2l-c

e sh Bz wx, ds ac 2 x Dup.

I Ds Sh Bz Wx Wx Bz Sh Ds

 

 

 

 

 

 

Nor. ¢ sh bz wx
Ace ac, Ac ac ¢
4785-9 4785-15 | 4786-75
Kernel type x x x Totals
48764-1 4876A-1 | 4876A-4 |
I Sh Nx 22% 25* 23% § 70
(no obv. wx spots)
I(-c), Sh,Wx-wx 37 61 45 143
I sh wx 14 10 10 34
I Sh wx 48 49 37 | 154
C Sh Wx 5 14 8 289
Cec, Sh, Wx-wx 22 31 15 | 68
C sh wx 169 175 88 432
Odds 0 1C Sh wx 0 4
non-var, |
Totals 317 366 226 | 909
* Some probably I Ds Ac but no losses to give wx during
dicentric formation
Summary $

—

(minus few UE)
c.0o. 4)

(plus few

C.0, 4)

| 308 Duplication : 601 normal “© “%)
supplement to table 2l-c
a

 

 

3 Ac Ac Ac Ac
v boop 1 4 .
I Ds Sh Bz Nx Wx Bz Sh Ds
mite ines fete a ca alle Ha nen Ae te tig eet \ 9 8 nearer anne
¢.d8 sh B20 WE
we po

Non crossovers ~

\ ~, 5 ac = T-c Sh Wxrewx
Dup. I Ds Sh Ba Wx Wx Bz Sh Ds.
1 ac = Sh Wx nonevar.

Norm. C ds sh bz wx Ac & ac «= C sh wx non-var, = 432
Region 1
Norm. I sh wx Ac & ac = I sh wx

7.3 ac = Cec Sh Wxewx (c areas Wx-wx
Dup. ¢ Ds+ Sh Bz Wx Wx Bz Sh Ds® or wx)
‘lac = C Sh Wx non-var.

Region 2

Norm. I Ds sh wx Ac & ac «= I sh wx

53 Ac = Cec Sh Wxewx (c areas wx)
Dup. C ds Sh Bz Wx Wx Bz Sh Ds
Nl ac 2 ¢C Sh Wx non-var.

 

 

Region 3
=~ 8 Ac = I(-c) Sh-sh wx (deficient
Norm. I Ds Sh wx — classification)
1 ac = I Sh wx
. 3 Ac = Cec Sh Wx-wx (c areas wx)
Dup. ¢ ds sh Wx Wx Sh Ds® .
~~ J] ac = © Sh Wx non-var,
Region 4
3 Ac = I(-c) Sh Wx-wx
Norm. I Ds Sh Wx
1 ac = I Sh Wx
3 Ac = C-c Sh Wx-wx (c areas wx)
Dup. C ads sh x Wx Sh Ds®
lac
Regions 2 + 3
Norm. © Sh wx ac & ac = C Sh wx non-var.
Normal chromatids: Non c.o,. = 432 = C sh wx
Reg. 142 = 34 = I sh wx c.o, Ito Sh= 5.8%
Reg. 3 = 134 =I Sh wx * Sh to dx = 22.4%
Reg. 2+3 = 1 = ¢ Sh wx

Total 601
Table 22

1

Dup. I Ds” Sh Bz Wx Wx Bz Sh Ds® 9 x C sh bz wx, ds ac o6

Norm. C sh bz wx

 

4876A-1 4876A-2 4876A-4 4876A-5

 

 

Kernel type x x x x Totals
4803-27 4807-1 4804-11 4806-11
I Sh Wx 117 110 125 154 506
(58 are (52 I-c Bz-c bz)
I - © Bz-C bz)
I Sh wx 22 52 40 22 136
(8 I -C Bz- (16 I-c Bz -
C bz) C Bz Sh)
I sh wx 3 3 10 7 23
C Sh Bz wx oe 49 71 2g 181
(6 C Bz-C bz)
C sh b2 Wx 0 0 0 0 0
Cc sh bz wx 139 128 172 183 622
Odds 0 0 0 0 0
Totals 313 342 418 395 1468

 

665 I : 803 ¢ 687 Wx = 781 wx 823 Sh : 645 sh
Supplement to Table 22

 

i a 3 4
ri yo « ' 2

a I Ds Sh Bz Wx Wx Bz Sh Ds

—_ Cds sh bz We,
2

Non-crossovers

Dup. I Sh Bz Wx Wx Bz Sh Ds = I Sh Wx

Nor. C ds sh bz wx = C¢ sh bz wx
Region 1 (I to Sh)

Dup. C Sh 3z Wx Wx Bz Sh Ds® = C Sh Bz Wx

Nor. I sh bz wx = I sh wx
Region 2

Dup. C sh Bz Wx Wx Bz Sh Ds = ¢ Sh Bz Wx

Nor. I Sh 3z wx = I Sh wx
Region 3

Dup. C sh bz Wx Wx Bz Sh Ds = © Sh Bz Wx

Nor. I Ds Sh Bz wx = I Sh wx
Region 4

Dup. © sh bz wx dx Bz Sh Ds = C¢ Sh Bz Wx

Nor. I Ds Sh Bz dx = I Sh Wx

C.o. Ito Sh = 2.9%

C.o. Sh to Wx = 17.5%

= 622

= 136
Table 23-a

 

 

 

 

 

 

 

*
“att f.i.
C sh bz wx ds ac 2@ x DUP. © sh bz Vx Wx Bz Sh Ds Me nob 3
Norm. C sh bz wx °
4898-1

4808-19 4803-24

Kernel type x x Totals
4898-1 4898-1
C Sh Bz Wx not obv.var. 49 25 74
C Bz - C bz, Sh, Wx-wx 68 40 108
C sh bz Wx not var. 13 5 18
C sh bz wx 284 145 429
Totals 414 215 629
CeOe
C sh bz ix V. wx Bz Sh Ds O—-.-
c sh bz wx a
“Om ;

Normal cnromosomes 9.

Non=¢.0. = 429

C06 = 18 = 4,03%

Total = 447

X Qo Lets thos Te © Loy - Vole" atole . au} ox dulictow 4 alll A
We caweqatiod owls Woo of porsbly
Table 23-b

X

Dup. C sh bz Wx Wx Sh Bz Ds 9 x C sh bz wx, ds ac c¢

Norm, C sh bz wx

 

 

 

Ae Ac
Kernel type 4898-1 x 4803-27
C Sh Bz Wx* 139
C sh bz Wx non-var. 2
GC sh bz wx 120
Total 261

 

* Variegation class not recorded because of Ac Ac condition

in endosperm.

 

 

fo .O6
_ _Cshbz Wat Wy cs Beshos
an aa a ;
- ©...
Normal chromosomes 9;
Non-crossover = 120
C.0. = 2 = 1.63%

Total 122
Table 24-a

C sh bz wx, ds ac 2 x Dup. C sh bz Wx Wx Bz Sh Ds* Ac Ac ¢
Norm. © sh bz wx

4898-3

 

4804-2 4804-18
x Totals

Kernel type x
4898-3 4898-3

 

 

 

 

 

C Sh Bz Wx 18 11 29
non-vVar,
C Bz = C bz, Sh, Wx-wx 78 81 159
C sh bz Wx 4 14 18
C sh bz wx 206 357 563
Totals 306 463 769
Os
Cshbz ow¥ wx Bz Sh s®@
Site we

Normal chromosomes q: me
Non-crossovers = 563
C.O.4 = 18 = 3.2%

Total 581
Table 24-b

C sh bz Wx Wx Bz Sh Ds® @ x GC sh bz wx, ds ac ¢

C sh bz wx

 

 

 

Ac Ac
| 4898-3,
Kernel type 4898-3 x 4803-38
C Sh Bz Wx* 73
C sh bz Wx non-var. 3
C sh bz wx 63
Total 139

 

¥

Variegation class not recorded because of Ac Ac consti-
tution of endosperm.
C.0.

y . .f.1.
C sh bz Wx Wx Bz Sh Ds

 

Normal chromosomes 4! o————

Non-crossovers 2 63
C.O. = 3 . 4.5%
Total 66
Table 25-a

aX
Dup. C sh bz Wx Wx Bz Sh Ds Ac Ac @ x C sh bz wx, ds ac ¢
Norm. 6 sh bz wx

 

 

4898~4
Kernel type 4898-4 x 4804-14
C Sh Ba Wx 24
C sh bz Wx non-var. 0
C sh bz wx 12

 

Totals 36

 
Table 25-b

a
C sh bz wx, ds ac 2 x Dup. © sh bz Wx Wx Bz Sh Ds

 

 

 

 

 

 

 

 

Norm. C sh bz wx Ac Ac ¢

4898-4

Kernel type 4803-18 x 4898-4
C Sh Bz Wx not obv. var. 15
C BZ - C bz, Sh, Wx-wx 65
C sh bz Wx non-var,. 6
C sh bz wx 157
Totals 253

c.0,
C_ sh bz Wx ve Wx Bz Sh Ds ae
¢ sh bz wx oT
Se

Non-c.o. in normal cnr. class = 157
C.O. 6 = 3.6%

Total 163
C sh bz wx, dS ac? x

Table 26-a

Dup. C sh bz Wx
Norm. C Sh bz wx

f.1

Wx Bz Sh Ds °°
4898-2

Ac Ac ¢

 

Kernel type

4801-37 4803-28 4805B-22 4880c~2

 

 

 

x x x x Totals
4898-2 4898-2 4898-2 4898-2
(tiller)
C Sh Ba Wx 145 125 154 88 512
(Majority obviously
var. C Bz - C ba, Wx-wx)
C Sh bz wx 143 126 121 150 540
Non=vaer.
C sh bz wx 67 68 75 64 274
C sh baz Wx 2 3 2 3 10
Non-var.
C Sh bz Wx 3 2 0 1 6
Non-var,.
Totals 360 324 352 306 1342
512 Bz : 830 bz
 

 

Supplement to table 26-a
Gametes produced by 4898-2
\ a
r he \ .
C_sh bz ix Wx Bz Sh Ds.
C Sh bz WX
OH
Non-crossover:
Dup. © sh bz Wx Wx Bz Sh Ds = C BZ - C b2,Sh Wx-wx
Norm. C Sh bz wx = C Sh bz wx
Region 1
Dup. C Sh bz Wx Wx Bz Sh Ds =C Bz-c bz, Sh, Wx-wx
sorm, C sh bz wx = C sh bz wx
Region 2
Dup. C Sh bz wx Wx Bz Sh Ds = C Ba-C¢ bz Sh Wx-wx
Norm. C sh bz Wx = C sh bz Wx
Regions 1 + 2
Dup. © sh bz wx Wx Bz Sh Ds = C Bza-c bz, Sh, Wx-wx
Norm. C Sh bz Wx = C Sh bz Wx

Total

=

540

274

10

6

 

830

Cross-over percentages based upon the population of recovered

normal chromosomes:

Kernels
C. o. Region 1 274+6 = 280
C. of Region 2 10+*6 = 16
Ce. Of Regs. 1+2 6 =

Per cent
crossing-over
= 33.7%
= 1.9%

0.72%
Table 26-b

Dup. C sh bz Wx Wx Bz Sh Ds

 

ac Ac @ xX C sh bz wx, ds ac ¢
Norm. C Sh bz wx

4898-2

 

Kernel type 4898-2 x 4803-27

 

C Sh Bz Wx 180
(Some obviously variegated )

 

C Sh bz wx 120
C sh bz Wx 3
C sh bz wx 38

Totals 341

 

 

 

Summary = 180 Bz : 161 bz No selection against duplication
183 Wx ; 158 wx chromosome ‘9
\ a
re y
C sh bz Wx Wx BZ Sh Ds — 6
C Sh b2 wx a
Oe
C.o. region 1 = normal chromosome

with C sh bz wx = 38 = 11.1%
C.o. region 2 = gemes- normal chromosome with C sh bz Wx = 3 = 0.88%
Table 26-c

f.l.

 

Norm. C Sh bz wx
4898-2

 

Kernel type 4790-21
4898-2
C Sh Wx with few small c wx spots 38

C = c, Sh - sh, Wx-wx 89
(c areas wx)

C Sh wx non-variegated 83

 

C sh Wx 2
C sh wx non variegated 58
Totals 270

 

Summary = 210 Sh : 60 sh
129 Wx : 141 wx
Supplement to

Non-crossover chromatids
Dup. C sh Wx Wx Sh Ds, Ac

Norm. C Sh wx, Ac

‘C. Of Region 1
Dup. C Sh Wx Wx Sh Ds, Ac

Norm, C sh wx, Ac

C.o. Region 2

Dup. C sh wx Wx Sh pstel-

Norm. C sh Wx Ac

table 26-c

»Ac™

Crossing-over percentages based

Total = 143

Wx Wx Sh Ds

a
v few late

ae ..
C-c Sh Wx-wx
C Sh wx = 83
C-c Sh Wx-wx
C sh wx = 58
C-c Sh wx-wx
C sh Wx = 2

on normal chromosomes =

Cross-overs, Region 1 = 58 = 40.5%

‘ tt tt B= 2x

1.

3%
Table 27-a

Dup. C sh bz Wx Wx Bz Sh Ds

Norm. C sh bz wx

Ac ac 2 x C sh bz wx, ds ac

é

 

 

 

4877C-7 4878D-2 4878D—-5
Kernel type x x Totals
4807-1 4804-11 4804-11
C Sh Bz Wx 229 190 419 155
(not classif. for var.)
C sh bz Wx 2 2 4 0
C sh bz wx 230 170 400 148
Totals 461 362 823 303

 
Table 27-b

C sh bz wx, ds ac 9 x Dup. C sh bz Wx Wx Bz Sh Ds

Norm. C sh bz wx

 

 

Kernel type 4805B-25
4877C-5
C Sh Bz Wx 57
not obviously var.
C Bz - C bz, Sh, Wx-wx 355
(bz areas wx)
C sh bz Wx 0
C sh bz wx 2359

 

Totals

531

 

Ac ac

é
Table 27-e¢

¢ sh Bz wx, ds ac 9 x Dup. C sh bz Wx Wx Sh Bz Ds 4g) ga

Norn.

C sh bz wx

 

aeb=1I idl 86 4785- 24 4969-11

 

 

 

Kernel type x Totals
48770-5 48770-5 48770~6 4878D-6

C Sh Wx 51 67 92 57 267

non-var.

Cee, Sh, Wx-wx 38 60 59 35 192

(c areas wx )

C sh Wx 3 4 8 0 15

non-var,

C sh wx 278 230 200 239 947
Totals 370 361 359 331 1421

 
Table 27-d

Dup. C sh bz Wx Wx Bz Sh Ds

Ac ac, self-pollinated
Norm. C sh bz wx

 

Kernel type | 4877C-4 4878D-6 Totals

 

C Sh Bz Wx 351 362 713
(not classified for var.)

C sh bz Wx 6 4 10

C sh bz wx 206 185 391

 

Totals 563 551 1114

 
Table 28

Dup. C sh Bz Wx Wx Bz Sh Ds 2 x C sh bz wx, ds ac ¢

Norm. C sh ba wx
Ac ac

 

Kernel type 4878D-1 x 4804-11

 

C Sh Ba Wx 166
(not exam. for var.)

 

 

 

 

C sh bz wx 162
C sh Bz Wx, non-var. 1 {cross-over, region 2)
C sh Bz wx, non-var. 27 (cross-overs, region 1
Totals 356
© ®
a _& sh Bz ix’ Wx Bz Sh Ds O----
C sh bz Wx
a
On
Among C sh kernels = normal chromosome 9
Non-c.0, = 162
Reg. 1 = 27 = 14.2%

Reg. 2 = 1 = 0.52%
Totals 190
I Ds Sh Bz wx
C sh bZ wx

Table 29

Ac ac 2 xX C sh bz wx, ds ac ¢

 

4877s-1 48774-6

 

 

Kernel type x x Totals
4807=1 4807-1

I Sh* 113 25 138
Not obviously var.
I Ba-c Ba-C bz, Sh 87 17 104
I sh* 4 1 5
Not obviously var.
C Sh Bz 4 1 5
C sh Bz 0 1 1
C sh bz 220 35 255

Totals 428 80 508

 

* Probably includes some I bz ~ C bz var. but bz areas

not recognized in Ac Ac ac constitutions.
Table 30

C Sh Bz wx

C sh bz wx 9 x C ah bz wx ds, Ac ac ¢

 

4877E-1  4877E-2

 

 

Kernel type x x Totals
4809-10 4809-10
C Sh Bz, non-var, 217 193 410
C sh BZ, non-var, 12 5 17
C Sh bz 10 3 13
C sh bz 250 193 423
Totals 469 394 863

 

C.o, Sh to Bz = 3.47%
Table 3l-a

Plants from C Bz - C bz, Sh-sh, Wx-wx kernels of 4892 x S sh bz wx, ds ac d

v
Dup. C sh bz Ax Wx Bz Sh Ds ac ac Q
Norm. C_ sb. bZ wx

 

 

nS ae
4A892B-1 4892B-2 4892B-3 4892B-5 4892C-1 4892C-3
Kernel type x x x x x x Totals
4804-21 4804-21 4804-21 4804-21 4804-7 4804-7

C Sh Bz 4x 310 186 261 172 188 128 1245
var. and non-var,
C sh bz Wx 4 2 4 1 0 1 12
C sh bz wx 334 205 253 132 216 117 1257

 

Totals 648 393 518 305 404 246 2514

 
Table 3l-b

Dup. C sh bz Wx Wx Bz Sh Ds Ae ace
Norm. C sh bz wx

C sh bz wx, ds ac @ x

4892 culture

 

4804-7 4804-22 4801-30 4801-32 4804-28 4803-48 Totals Grand

 

Kernel type x x x. x x x for totals
4892B-3 4892C-1 4892C0-3 4892C-3 4892c-3 4892c-3 4892C0-3.

C Sh Bz Wx 26 64 34 47 40 29 150 240
Non-var.
C Bz - C bz, Shesh, Wx-wx 35 46.. 37 53 45 29 164 245
(bz areas wx)
C sh bz Wx 2 3 4 2 1. 1 8 13
Non-var.

C sh bz wx 211 197 200 208 79 159 646 1054

 

Totals 274 310 275 310 165 218 968 1552

 
Table Slec

Dup. C sh bz Wx Wx Bz Sh Ds
Norm. C sh bz wx

ec sh Bz wx, ds ac? x ae ac 6

 

 

Kernel type 4785-82 x 4892C-6
C Sh Wx, non-var. 18
C-c, Sh-sh, Wx-wx Se

(ec areas wx)

C sh Wx, non-var. 1

CG sh wx, non-var. 197

 

Total 248

 
Norm. C sh bz Wx
Norm. CG sh bm wx

Table 32-a

Self-pollinated

 

 

 

7 7 4893-1 4893-3
ernel type selfed selfed tovets
C sh bz Wx, non-var. 129 90 219
C sh bz wx 35 o1 66
Totals 164 121 285

 
Table 32-b

Norm. C sh bz Wx
9 x C sh bz wx oc
Norm. C sh bz wx

 

 

 

Kernel type 4892p
4803-30

C sh bz Wx 245

C sh ba wx 234

Totals 479

 

Table 32-e

C sh bz wx 29 x € Sh_bz Wx é

 

 

C sh bz wx
4901G-6
Kernel type 7
4893-3
C sh bz Wx 124
C sh bz wx 138

 

Totals 262

 
Table 33-a

Bee.
C sh bz wx,ds ac? x Dup. C sh hz Wx Wx Bz Sh Ds

 

Norm. c sh Bz wx normal

Ae ac

 

 

4804-29
Kernel type x
4896
C Sh Bz Wx non-var,. 113
C BZ - Cc bz, Sh, Wx-wx 93
C sh Bz wx 195
C sh bz Wx non-var, 0
C sh bz Wx 38
Odds 0

 

Totals 439

 
Table 33-b

Dup. C sh bz Wx Wx Bz Sh Ds

 

9 x C sh bz wx ds ac oo
Norm. ec sh Bz wx (normal)

 

 

Kernel type 4896 x 4803-27
C Sh Bz Wx non-var,. 195*
C sh Ba wx 184
¢ sh bz Wx non-var. 3”
C sh bz wx 1?
Odds 0

 

* 42 were clearly C Bz - C bz Sh Wx-wx
+ 2 probably not cross-overs but due to deficiency
Supplement to, table 33

A

¥
C sh bz Wx Wx Bz Sh Ds

 

ec sh Bz wx da

Non~crossover gametes

Ac

Dup. C sh bz Wx Wx Bz Sh Ds”
t AN ac
Norm. c sh Bz wx as Ac and ac
(normal ) -
Region 1

Norm. C sh bz wx ds Ac and ac
Ac

7
Dup. c sh Bz Wx Wx Bz Sh Ds
Vac

Region 2

Norm. C sh bz Wx ds Ac and ac

vac
Dup. ec sh Bz wx Wx Bz Sh Ds
Nac

ec

ee ee

eta oi

71
= C Bz
= ¢ Sh
= ¢sh
= ¢ sh
='C Bz
= ¢ Sh
= ¢ sh
= C Bz
= ¢C Sh

0

kernel appearance

- C bz, Sh, Wx-wx dywrmed

Bz Wx

a b
BZ Wx = 195 184
ba Wx = $8 1?

-~ C bz, Sh, Wx-wx

Bz Wx

bz Wx = 0 1
prob.
- C bz, Sh, Wx-wx

Bz Wx
Table 34

C sh bz wx ds ac @ x I Ds Sh Bz wx Ac ac 6

C ds Sh bz Wx

 

 

4806-5 4B80C-3 4806-5
Kernel type x x x Totals
, 4883A-1 4883A-1 4883A-2
I wx , 72 76 80 228
Ipz-C Ba-C bz, wx 44 58 80 182
C bz Wx 139 178 173 490
I Wx - 27 29 14 70
C Bz wx 9 11 4 24
C BZ - C b2, wx i 3 2 6
I bz - C bz, Wx-wx 3 4 2 9
(bz areas Wx-wx)
I Bz - C Bz - C bzZ,Wx-wx 21 18 18 57
(bz areas Wx-wx)
Cc Sh bz wx 48 60 40 148
Others 2C Bz - 1 trans- 1 trans- 5

C bz,Wx-wx* posed De= posed Ds=
I Sh Bz Ds 1 Sh bz,
wWx-wx*

 

Totals 366 438 415 1219

 

* Probably from Ds mutation in div. to give sperm = loss of I
but not Bz.
C.0. I to Wx (excluding odds) = 25.8%
Supplement to Table 34

C sh bz wx ds ac 9 x I Ds Sh BZ wx gc ac g
C ds Sh bz Wx

1 2 3
I Ds Ba wx

C ds bz Wx
Non-crossovers

Ac = I BZ - C Ba =-C bz, wx = 182

I Ds Ba wx <

ac = I wx = 228
Cds bz Wx Ac + ac= C bz Wx = 490
Region 1
Ids bz Wx Ac + ac © I Wx

7 Ac = C Bu - © bz, wx = 6*

C Ds BZ wx \

ac = C Bz wx

Region 2
vac = Ibz- C bz, Wx-wx = 9
I Ds bz Wx \
ac = I Wx

C ds Baza wx Ac + ac = C Bz wx

Region 3

, Ac = I BZ =- C Bz -C bz, Wx-wx = 57

I Ds Bz Wx \
ac = I Wx

C ds bz wx Ac + se = C Sh bz wx = 148

 

Reg. 1 + §

i ds bz wx Ac + ac = wx

AQ = bz, Wxewx = 1
CG Ds bz wx © 3h bz,

I
C
ac = C bz Wx
Reg. 2 + 3
I

yac = bZ - C DZ, Wx
I Ds bz wx

7 ac = I wx

C ds Bz Wx Ac + ace C Bz Wx = 0

* Several of these probably from germinal losses of I in an
I Ds Sh Bz wx chromosome.
Max. c.o. Reg. 1 = 2%
Table 35

C Ds Sh Bz wx
Ac ac 6 (4883B)
C ds Sh bz Wx

C sh bz wx ds ac @ x

or

C Ds Sh Bz wx
Ac ae ¢ (4883¢C)
c ds Sh bz Wx

 

4804~13 4804-27 4801-1 4803-31 4806-2

 

 

Kernel type x x x x x Totals
4883B 4883B 4883C 4883C 4883C
C Bz Wx 12 20 16 14 17 84
Not obviously var.
C BZ - C bz, Wx-wx 15 18 25 13 16 87
(bz areas Wx-wx)
C Bz wx 61 70 81 56 50 318
Not obviously var.
C BZ - C bz, wx 60 57 51 44 39 251
C bz, Wx non-var, 123 158 119 124 122 646
C bz, Wx-wx 4 3 5 4 5 21
C bZ wx 33 52 29 22 29 165
Odds 0 0 2c sh 0 0 2
BZ wx
Totals 308 383 328 277 278 1574

 

Summary (minus odds)

740 Bz
838 Wx

832 bz
734 wx

°
*
°
e

Reduced numbers of Bz and wx due to:

Ds mutations in ¢ parent giving deficient chromosome 9
Supplement to table 35

Gemetes of 4883B and C

1 2
¥
Ds BZ WX ie ae
ds bz Wx
Gametes Kernel type
Ds Be wx ~ *° * C Ba-C bz, wx = 252
\ ac = C Bz wx = 318
ds bz Wx Ac + ac = C bz Wx = 646
Region 1
y Ac = C bz, Wx-wx* = 21
Ds bz Wx \
ac = C bz Wx
ds Bz wx Ac + ac = C Bz wx
Region 2
, Ac = C Bz - C ba, Wx-wx*e 87)
Ds Bz Wx \ |
ac = C Bz Wx = 845% Total 336 = 21.3%
ds bz wx Ac + ac = C bz wx = 165
*

Wx-wx from breakage-fusion-bridge cycles following a Ds mutation

giving a dicentric chromatid.

Crossing-over Ds to Bz =

Bz to Wx = 21.3%

=

Ds to Wx

 

5.2% Based on var. kernels
Non ¢.0. = 251

26.5% Reg. 1 = 21 = 5,8
Reg. 2 = 87 = 24,2
Total 359
Table 36

ec sh Ez wx, ds ac 2 C Ds Sh Bz wx Ae ae o

€ ds Sh ba wx

 

 

4785-21 4787-13
Kernel type x x Totals
4883B 4883B
C Sh Wx non-var. 128 142 270
C-c, Sh-sh, Wx-wx 20 18 358
(c areas Wx-wx)
C Sh wx non-var. 88 97 185
C-c Sh-sh wx 47 40 87
Odds 1 colorless Sh-sh, 1c sh wx 2
Wx-wx

 

Totals 284 298 582

 

308 Wx : 272 wx (minus odds). Reduction in wx class due to
Ds mutations in sporophyte of ¢d eliminating the C Ds Sh Bz wx
chromosome because of deficiency formation.

30.4% crossing-over Ds to Wx
Supplement to table 36

Gametes formed by 48838

C Ds wx
Ac ac
C ds Wx
Non=-crossover
y Ac = C-c, wx = 87
Cc Ds wx \
ac = © wx

Cds Wx Ac + ac = CG Wx

Crossovers
7 Ac = C-c, Wx-wx = 38 = 30.4% of variegated
C Ds Wx kernels
Nac = 6 Wx Crossing-over Ds to Wx

C ds wx Ac + ac = 6 wx
Table 37

q
e shwxdsac? x © DS SH WX Jo ae g

e ds Sh wx

 

4787-20 4786-74

 

Kernel tyne x x Totals
4883C 48836
tiller main stalk
G Sh /x non-var. 15 25 40
Cec, Sh, wWx-wx 1é€ 11 29

{ec areas ix-wx)

 

C Sh wx non-var,. 49 61 110
C-c, Sh wx 3o7 oe 69
e Sh J/x non-var, 77 lil 188
e¢ Sh wx o1 34 65

Totals 227 274 501

 

248 C 3: 253 ¢

*

257 Wx : 244 wx

29.4% crossing-over Ds to ix
Non cross-Ove

”
C Ds wx \

c ads Wx Ac +
Region 1

Cds Wx Ac +

ec Ds wx a

Region 2
7
C Ds Wx
\

c ds wx Ac +

Supplement to table 37

Gametes from 4883C C Ds wx

r
Ae
ac

ac

ac
Ac

ac

Ac
ac

ac

= C-c wx = 69
= © wx = 110
= ¢ Wx = 188
= C Wx

= ¢, Sh-sh, wx (difficult to classify)

ec Sh wx

C-c, Wx-wx = 29 = 29.4% of C-c kernels

C Wx about same as distance between
. C + Wx = 134 gametes in 501=
ec Sh wx 24.7%
Case I

Table 38

C Ds Sh Ba wx Ac ac 3

C ds sh bz wx

c sh BZ wx ds ac 2? x

 

 

 

4969-15 4785-23 4786-118 4785-8 4793-12
x x x x x Totals
Kernel type go, 4984 4884 4887B 4890-1
C Sh 131 96 63 89 104 483
Cec, Sh-+sh 86 85 96 80 102 449
C sh 207 197 141 192 174 911
Cec sh 1 7 4 5 4 el
1 Cec Sh 1 colorless
Odds 0 transp. Ds Sh wx* 0 0 6
1 colorless Sh* 1 pec.
2c sh wx C-c def,
Totals 425 389 306 366 384 1870

 

449 C-c Sh : 21 C-e sh = 4.5% crossing over Ds to Sh

* Due to loss of C in sperm from Ds mutation probably.
Table 39

 

ec sh a@x e sh Wx or ¢ Sh wx
Re e+ acac@? x Ke *—-—-—— +o
Re ++ Oe A@ ae
ec sh Wx € ds Sh wx

 

Kernel type 4793-17 4793-13 4793-14 4792-6 4793-7

 

 

x x x x x Totals
4882 4890D-1 4890D-1 4890D-~2 4890D-2
C non-var, 60 98 108 102 57 425
C=c, var. 65 68 94 92 85 404
ce 131 191 189 202 139 852
Odds 0 0 0 lc, Sh-sh, 1
Wx*
Totals 256 357 391 396 282 1682

 

* Probably from loss of ¢ throuzh Ds mutation leaving Sh in
chromosome with broken end. Sh-sh due to breakage-fusion-=
bridge cycle.
ec sh wx ds ac

2

Table 40

x
Re

ene

€

C

sh dx

Ac ac od

np

Ds Sh wx

 

 

 

Kernel type 4786-52 x 4882

C Sh wx non-var. 80
Cec, Sh wx 63
C-c, sh, wWx-wx 1
(c areas Jx-wx)
ec sh Wx 177
c Sh wx 1
e sh wx o

Totals 329

 
Table 41

ec sh wx ds ac 9 x. e—¢ ob Wx

1 eget ter cere

C¢ Ds Sh wx

Ac ace ¢

 

 

Kernel type 4785-4 x 4890D-l1
C Sh wx non-var. oo
Cec, Sh wx 32
ec Sh wx 80

 

Totals 147

 
Transvosed Ds 4628

Table 42

C sh bz wx ds ac @ x I Ds Sh Bz Wx Ac acd

C ds sh bz wx

 

5402-9 5402-10 5402-12 5402-14 5402-17 5403-67 5401-68 5403-71 5401-1 5403-10

 

Kernel Type x x x x x x x x x x

5492-1 5492-1 5492-3 5492-3 5492-3 5492-5 5492-5 5492-5 5499-6 5492-6
I Sh Wx 49 51 89 78 79 59 53 74 46 69
I-C Bz-C bz, Sh-sh 40 42 71 76 76 84 62 86 53 80

Wx-wx

{15 Bz 15 Bz 12 Bz 14 Bz 25 Bz 19Bz 29 Bz 198Bz 17 Bz
I Sh wx 15 20 14 21 15 34 20 42 28 29
I-¢c Bz-c bz-Sh wx 13 1? 12 14 16 27 30 36 29 23
I bz-C bz. Sh wx 1 0 1 6 1 3 1 2 1 0
I sh wx 4 2 4 10 7 5 6 11 4 9
I bz-C bz.sh wx 7 1 4 2 5 9 6 ? 5 2
Cc Sh Bz Wx 2 8 6 16 9 17 14 14 12 14
C Bz-C bz Sh Nx-wx 0 2 2 0 2 2 0 1 1 2
C sh Bz Wx 3 4 6 6 8 7 7 6 5 13
C sh b2 Wx 27 25 37 43 47 84 75 69 47 75
C sh ba wx 85 71 132 116 166 147 126 145 97 156
C Sh Ba wx 1 1 0 1 1 2 3 0 0 0

Odds 0 1cC¢ sh 0 1c¢ sh 1 1Ishic Bz-¢ bz 0 2I sh 1¢C Sh

Bz wx Bz wx Wx Sh, wx Wx bz Wx

1 I sh Wx 11 sh

1c sh Bz wx Wx

 
 

5400-20 5400-23 5400-50 5403-15 5404B-25
x x x x x Totals
54944A-1 5494A~-1 5494A=2 54944-2 5494A-2

56 85 36 .48 59 951
49 76 61. 85 76 1017
18 Bz 8421 Baz Yt Bz 5 Bz
16 24 22 15 6 321
18 19 24 17 17 312
2 2 3 1 2 26
5 4 2 2 4 77
2 3 7 4 3 67
4 3 6 1 11 137
0 1 0 1 0 14
5 2 2 4 § 83
24 60 47 34 44 | 738
101 158 138 96 141 1875
1 0 1 0 1 12

I sh Wx 21 sh Wxi1tIbz- QO 21 sh W#x cC sh BZ w -
c Sh bz c bz (1 var.) I sh Wx
wx sh Wx-wx

2
1

 
Table 43

e sh Bz wx, ds ac? x

I Ds Sh Bz Wx
Cc ds sh bz wx

Transposed Ds 4628

Ac ac ad

 

 

 

Kernel Type 5592-68 sete a _—* o502-25 oe 5892-57 5595-5 5592-56 5592-53 Totals
5492-1 5492-3 5492-5 5492-5 5492-6 54944(1) 5494A(2) 54944-2 5494A-2
Colorless Sh Wx 82 70 55 49 54 53 22 55 70 510
Colorless Sh, Wx-wx 80 67 54 Sl 42 Sl 29 85 81 540
Colorless Sh wx 53 31 49 41 47 47 6 48 32 354
Colorless sh wx 7 9 9 il 17 6 1 7 5 72
C Sh Wx 11 7 18 14 ii 8 3 7 2 81
C-c Sh. Wx-wx 0 1 4 0 1 0 0 1 0 7
(c areas Wx-wx)
C sh Wx, non-var. 54 42 80 65 52 40 10 59 53 455
C sh wx, non-var,. 143 122 96 110 120 112 46 105 153 1007
Colorless sh Wx 0 0 1 0 0 0 Q 2 3
Colorless sh @x-wx 2 1 0 0 0 1 0 4
Odds 0 0 0 lcshwx o 1} Cre Sh wx 0 0 2
of ¢
Totals 432 350 366 342 344 319 117 367 598 3035

 
Supplement to table 43

 

 

 

(1)(2)(3)
fi
I — Wx
C ds sh wx
Non-crossovers
wwe AC ™ colorless Sh-sh, Wx-wx 540
I Ds Sh Wx =~ ee, a
oe ~ ac = colorless Sh Wx 510
C ds sh wx, Ac and ac = C sh wx, non-var, 1007
Region 1
I sh wx, Ac and ac = colorless sh wx_
_~- Ac = Cec, Sh Wx-wx (c areas Wx-wx ) 7
C Ds Sh Wx — eee bs,
“~~~ ae = C Sh Wx, non-var, .
Region 2
I Ds sh wx, Ac and ac = colorless sh wx Ce Og

C ds Sh Wx Ac and ac = C Sh Wx, non-var.— gL

 

Region 3

I Ds Sh wx Ac and ac = colorless Sh wx (Ac = Sh-sh var.) 354

C ds sh Wx Ac and ac

C sh Wx, non-var. 455

 

 

Crossing over, regions 1 + 2 = 160 = 5.2%
" " region 1 = 7x4 = 28 = 0,9%
" " region 1, C class = 14

" " region 2, C class = 75