Vebruary 15, 195)

Conclusions on c-ml; outline of bz-ml; begin c#m?2,
I, Review of previous discussion:
1. Considered the origin of mutable ec from normal 6,

2. Heviewd the evidence suggesting that it arose from transposition of Ds
to thelocus of the normal ©,

3- Discussed changes in state of c-ml: The ratio of mutatkons to C to

dicentric forming events at Ds.

lL. Considered the moaning of this with regard to action of Ds whee no
phenotynic changes other than dicentric formation covld be observed,

5. Conclusion drawn that the number of changes at a mutable locus may not
be revealed by study of one type of change -- the mutati-n, for example.

i

Other changes occur -- "hidden mutations", a Rees deb eraon ok oun,

6. The stability of the changed states: ‘hose giving high ratio of
mutation to G ave much more st-ble in action in subsenuent eeneraticns than
those giving high ratio of dicontric formations at c-ml,

7. The st-tes of many mutable loci of considerable irmortance, The
presence of hi den mutations susvected or revealed in many cases, These
will apnssr as the diseussicn continues,

II, Continuation of discussion of behavior of ceml, Begin pate 7 of outline
of February ll,

1. Origin of stable ¢ from c-ml

2. The action of Me on e-ml and Dg when in same cell -

3. The ecntrol of Ac on time and place of mutaticns: Dosares;

Stabilized-Ac, .
Hy Ube Wyk Curne 9) Wirg ered Wo oon yah mebaliag ut
The origin and behavior of bz-ml

I, Kernel neving mutations to Bz first noted in cross of:

C sh bz wx ds ac female x I DgSh Bz Wx Ae male
Mer e

+

 

C dssh bz wx ac Oy
“St
a). the appearance of this kernel: C sh bz Wx background with ereas of 5
Bz.wx, Also, areas of wx noted in the non-Br areas, Like v
original c-ml xernel, in this respect, at.
“
b). The study proved that a mutable bz locts present ina C sh Bz Wx SS
chromosome. 5
¥

Probatly appeard because of a crossover, I to Bz. C sh bgt

- - ; an t. ‘ , (p=, < o
Vy rk chic — WOU an paul 6 ete @e us, Gears . Wepuurk : " =] Bayan »7t 4h : qeulius he .
2. The mutations proved to be Ae controlled, Photo of ear illustrating

linkare to sh and ratios in sh Classi. 4 .
H® ¢' C Sh Bz Wx AC
yw “AY Cosh bz wx ds ac female x C sh bz-ml Wx “ac
 

 

\ a
The gametes: Sh bz* Wx Ac
Sh bz-ml wx ak
Constitution of kerneal Avpearance of kernel
Bhh-crossovers C Sh b2S Wx Ae and ae C Sh bz Wx, non-var,

. (f° sh bz-ml wx Ac C sh bz wx, var for 5z;
we \ var for wx
€< lo sh bz-ml wx ac C sh bz wx

Cross-overs, °C Sh bzeml wx Ac C Sh bz wx, Par for Bz,

Rogion 1 4

L. " ac C Sh bz wx, non-var,
C sh bz Wx, Ac and ac C sh bz Wx, non-var,
Re oo
Region 2 C Sh bz® wx, Ac and ac CG Sh bz wx
(¢ sh bz-ml Wx Ac GC sh bz Wx; var for Bz
Kel var. for wx
LC akly Wy Or & be Wt

3. If same male crossed to c sh bz wx ds ac, the variegation for mutations
and for décentric breaks readily seen on the ears

pwd uy Appearance of kernel: The dicentric breaks:
3 Ww
CR UY C “Whe

\- Cu, Coe
wr

  

 

Photo of esr 3 of kernels; pass around cars,
-3-

Rec, Feb. 18 The Urigin and Behavior of c-m2,

I, History of the origin must begin with original plant that underwen: the
chromosome tyne of breakace-fusion-breige cycle,

1. Yrigin of this plant: Cut |
7 Wt
apa abe Me
a). the cross: a poe Q 4 oo Oey - one
Iwy Ck nee oe
mg a CM OA a,

b). the kernel selected: “~roken chromosome from male and female:

fom + 9, cule Lh fest a

ec). The plant from this kernel: Number 2-B, Main stalk and tiller
self-polli nated: bat
GeO ‘|

? A Say om
oy:
a ALE ~ 4
(ae Iw
— pert

Goya d). Cytology of the tiller: The genetic constitution wituin each chr:

~

t 3 __ —
cor \ fe . ; 1 ~
v) o
{ yd L Shy loe po Cy
2. The seedlings from the kernels on selfed ears:

Main stalk: All seodlings green,

*he tiller: some kornels derived from C class showed variegat nfor
pale-green to green, Proved to bes:

an
we C wo} LD se

et

3. Plants grown from these seedlings -- both var. and mreen, in field
under culture number 3592, sd

We

Pia 1 2 +

lh. the green plants self-pollinated, The variersated vlants too weak,

5. Aonearance of kernels on the ears: New mutables ap eared to be
segregating,
“hese were, (1) white to yellow endosperm

(2) altered starch constistoney -- like wx to Wx
and wx to wx but staining showed all Wx,
(3) Dicentric breaks -- like Ds-f.1,
6. Kernels on self-pollinated ear of one plant, 3592A, showed var. for
starch consistency. - °
a). the constitution of chromosomes 9 in this plant:

ch B2
LY C

x +.
Pd I ShPy ur ° - To

Plants from (aes

7e/The I Wx kernels grown in following summer under culture no, ooo A

 

“he C_\Wx kernels were in B of this evlture.
8, Various tests made wit: these plants; One was to self-pollinate the
ears and to cross to e sh Bz wx plants,

The appearance of the kernels on the ear derived from self-pollination of
hOOO0B=2
one of these plants: Variegated kernels and the non-varierated kernels:

Cne-fourth of the kernels were colorless and the majority of them
showed speckles of color,

In cross to ¢ sh wx slants, C Wx, non-variegated kercels and kernels with
areas of color in a colorless background apverred, The type of color
produced in the different areas differed markedly from that produced by c-ml.

The crosses to plants carrying C, no varierated kernels appeared,

Apveared, the efore, that a new mutable c, derived from a previously

normal C locus had been produced,

II, The tests of this new mutable Cc, designated c=m2,

1, Plants grown from the various types of kernels on the self-pollinated
ear and on the ear derived fem the cross to e sh WXe
plants derived from the
2. Tests made, the cro.ses of the/variegated kernels on the self-
pollinated ears:

a). Self-pollinated: Acain, majority of kernels showed some color, This
as small specks of color and not too many of them, ,

b). In crosses to e'sh wx: “early all of the kornels were varliegoted
but the patches of color were much larger than on the self-pollinated ear,
The types of color patehes were not all alike, 4 wide range in intensity of
color and in its distribution witnin a colored area,

ec). the male gametes -- em2 Sh Wx. On ears, a few areas of wx seen
in the majority of the e to C variegsted kernels but not many of them.

ad). The behavior very much resemblcod a mutable that was Ac controlled,
3. the tests for Ac -- these conducted, c-m2 proved to be Ac eontrolled
as was c-ml, hz-ml, The same Ac in its action altnough the derivation

differed. Plant OO0B-2 was Ac/Ac in constitution:
Cem? ShnBz Wx Ac

 

C Bh Bz Wx Ac
III, The tyne of variegation produced by c-m2, prpr constitutions -- red
— shades.

1 Generals:
1, Areas with very pale pink color to those with farily deep color,

2, Areas thet seem to resemble in all ways that produced by normal C

3. in the deeper pink areas, the color distrubution peculiar: like
that produced by a paint-brush:

é,

u eo

_

‘|

lh, These never present in the normal C ares, ¢ )

5. The pink-tyne mutations: form a quantitative s ‘ries, from almost
no color to very deep color but clearly distinguished from those having
the normal C phenotime,

2, The details of t-is veriegeticn’

The bogrders adi a pink and a regular Ctyne area?

 

Inmortant: The sharp border between the
the sharp border between the

nk and the colorless areas,

vi
G and the colorless area,

3

3e The pink areas: Sometimes the following seen:

2

we

In sone vink areas, section with deeper pink diffusing into ligt pink
sector, but witvin the pink sector, Gradiant of color change, Borders of
pink area sharp, as if mutation present in a sector bordering the pink

area that »roduces substance that the cells in pink sector can use to
increase pigment. (“ubstance 2), This mutation produces no color in cells
having it but the action in the pink sector reflects that such a mutation
occurred,
lL. The colored areas r-sembling normal C:

A section on border of such a sector can show deep color grading into
color of the sector:

 

here, also, looks as if a sector with a mutsetion is present to left of

mutant C area, this mutation does not produce any detectible color, but
its presence revealed by the border, The C collf can utilize t-is substance
to increase its pignent, (This si subtance 2,) The “hidden” mutotion

may be a very lifht pink, but"no ecclor seen,

5 Conclusions so far on mutations at c-m,

; : . 4 oe ‘ie sat! : :

a), Two main classes of visible mutations: he "pink’ serics, gives
sectors with verr feint wlor to those with yurtedecp color, In the
darker colors, the paint-brush like distribution of pigment over alcurone

layer is evicent,

b). The regular C tye mutation, only present in quantitative serics also,
Here, the color is smooth within the sector in eccontrast to paint-brus: tye
of mutants in pink seri-s,

c¢). Both rmitant types distinguashed by their reactions to one another

Pink - adjacent to "c"
3 2 j 2 ALT, * ~ 1 4 s
-+he borders between them: the diffusible substances produced:

Substance 1 produced by pink, can be used by the C mitant cells to
increase their color,

Substance 2, produced br "C" areas
inercase their color,

2.97 eo

» can diffuse into pink orees and

dad). the nidden mutations -- Production of either substance 1 or substence 2
in sector in wniich no color e2n se seen,

IV. The tests conducted to substantiate the above eonclusicns,.on the vroduction
of diffusible substances,

diffusible
1. Testa: Uhe/substonces produced by these mutations at c=m2 can be
used by “the normal C carrying cells to incroase their vigmentation,

the test cross: cen2 wx, Ac fena

eink ort ech 5: we MO

 

le x © Wx Ds ac male,

 

aemeg eee oe

 

ge apeweenn sree

4 — F)
~B-

i

ne constitution of the kernels examined:

2

Wx

' Wx

e-m2/ c-m2 / CG Wx Ds Ac Ac ac

Appearance of the sectorial kernels -- those with an early break at Ds in
the C Wx Ds chrcriosome?:

we * (ek LA
; ot ws
f a*& t os ye +c
c Xe , ; he
‘, ‘ : Y yy ‘4 a : :
¢ vo . . z ; f- 7 J aq
‘ . a . : yo :
ae ae . Lo:
‘ ° ¥ Cry
. : J pd

 

The control: ec wx /c wx / © Wx Ds, Ac Ac Ac:

The observatio s show tht two +

u
"pink" whieh produces substance 1,

yres of mutations occur at e-m2: ‘lo
incre se theiv color,

allowing normal C carrying cells to

and to full © tyve, that has no contrtbution of a
diffusible substance to the cells carrying the normal ¢,

Test 2 The germinal pi

nk mutations: ( Relatively stable in ~resence of Ac:
the cross: a

pink-carrying mutant vlant

 

x ce cece net

 

 

The kernels examined, those wi

mich have received a newly broken end
from the male parent, How this
developing kernel:

broken chromosome willl behave in the
oN Cc ~
(w) ~

ahh: C

The control: c/e female x broken chromoseme from
of variegation:

See Wuhan con

natant
Comp2erisons of th 1© color patterns produced. by two crosses described:

. SO * ~

\
| |

. i

t i \ f

\ /

\ é NN a
NX /
Cor-elusion: The germinal pink mutant is produce some substence = substance 1

that the normal C carrving cells can use to inercase color but, these

normal © carrying cells also produce substance that the cerminal pink mutents
can US, there are no sharp borders in any of the sectors produced torourn
the breakag-fusion-bridge cyc’eés.e

Test 3 Germinal pink mutations selected, Used as females in crosses

0 vlad te nartilintss

with plants carrying ceml, The Ac Ac kernels:
Seg

we

%
9

te ®

* a
; . *
‘ a)

£ *
a

Mutaticns to full C at c-ml occur late, to produce speckles with this dose

of Ac,

ta

The specks of color all have exceedingly deep centers, surrounded by
a diffusicn prim, the color gradually fading into that of the pink background.
Tests for substances 1 and 2,

V. The color produced by various doses of ©,

Quantitative -- hicher the dosc, the deeper the eclor: cxf, Went
Cee .
CCc
GGG

Cc c C |
cCccG ef te ee too
Cc. i
cecoc CL 2
eo a
Cc C
c CL CU
C \. C C C C wn cn ce een ei a
2.e the quantitative action of C, and the tests of Increase in color
produced by substance 1 when only I © present, suggests that the normal
C color produced by diffsrent doses of G reflect the amount of substance 1
present and produced by this C gene,
ly intensify the color produced in cells with
uienest intensity produced by the doseare studies,

that is -
a). Pink mutant can great
It often resembles the

1 G,
ances 2 can be produced without colox

“ome other factor

Conclusions:
Both substances 1 and substea
appeering -- see kernel tyves.
substance 1 present in excess.
e quantitative grades reflect the amomnt of
ark are present.
within each

In"pink mutantY
limiting, this may be substance 2
"Kukk C types" possibly the q

as the light colore and the derk colo

"aint brush’

In the
substance 1 produced,
also shown by the pattern of color distributi Lon

Differences
series
c broken pink

pattern vers the smath pattern,
/

pink -- increased color intensity.

tyoe of mutant sector or in the germinal mutaticns -- the
"Sink" :

Quantitative acticns witnin the
Lhe breskage-fusion-bridge eyelcs.
of

One, two and three doses o
in presence

The stability of the mutants produced by ceme,
le c¢ types recovered,

stab
stability with Ac, but new

anparently
i
or as germinals,

VI.
1. A number of
Ac.

ow considera:le

The pink mutants --
alterations or mutations arise, as sectors,
in absence of Ac, are stable,
sts insut

2.
f oink,

i
a

nk series,

many muta

Re The mutants o
4, The full C mtants -- probaly stable, but te
to full ¢ very

Be
The States of e=m2
1. Criginal state -- many hidden mutations;
1 a pi and
Photo of care

VII,
e. Changed state -- the mutations to dark vink
Lhe hidden class much reduced.

frequent,