April 7, 1930
Dear Charlie,
Things have turned up so fast since I wrote you that I am dashing off a line to bring things up to date. I have been working on [scientific formula, see Lister Hill?]. Among the regular normals diakineses shows: 3 small bivalves [?] r-g, number 2 and a small number 3 with a large terminal granule. It is not much larger than no. 2 without the granule. The spore stages show a regular number 1 and number 4 but a fairly large number 2 and the chr. with the granule which is number 3. I have enclosed a rather poor photograph of the spore complement -- 4 smaller chromosomes [diagram] in the sister plants which all D2 diakineses shows [diagram]
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If disjunction takes place half the time side-by-side and half opposite then we should expect 2 types of fertile spores and 4 types of sterile spores: [diagram]
If all the spores undergo the first division there should be seen the above 6 types in the proportions given.
I took a late stage, about second div. in spores in fertile spores. At this stage the fertile and sterile grains are clearly distinguishable. I counted the number of sterile spores with 2 nuclei, 1 nucleus, no nucleus and got 170 2-nucleated; 59 1 nucleated, 18 uncertain, 19 no nuclei. It looks as if among the sterile spores 3 of the combinations can go thru the first division and one can't. Of course we need more counts.
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To check this I have looked at the spore division figures and have found the normal chr. complement i.e. short number 3 and long number 2 as in photo; the interchange fertile gamete, long number 3 and short number 2 (which is possibly shorter than number 1) The sterile combination of two number 3s, a long and short and no number 2; the sterile combination of two number 2s, long and short and no number 3; possibly the long number 3 and long number 2. The other combination -- short number 3 and short number 2 I haven't found as yet but really haven't looked enough.
From this it looks as if number 3 has received more than it has given in the interchange.
Among the 2 nucleated sterile spores some have a few large starch grains and some have none -- there may be a universal difference i.e. 1/4 of the spores with grains etc, which might be related to a certain combination. [diagram]
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So much for the recent dope. I have much to do yet but want you to keep up with all that is going on.
As ever,
Barb.