Letter from Barbara McClintock to Charles R. Burnham
In this letter McClintock thanked Burnham for sharing his data and related some of her findings. She was particularly interested
in mutants of semisterile, and her research would result in an article in the "Proceedings of the National Academy of
Sciences" in 1930.
Item is handwritten. Item is a photocopy.
Number of Image Pages:
7 (415,271 Bytes)
1929-12-07 (December 7, 1929)
Burnham, Charles R.
Original Repository: University of Minnesota, University Archives. Charles Burnham Papers
Reproduced with permission of the University of Minnesota, University Archives. Charles Burnham Papers
Medical Subject Headings (MeSH):
Education and Research at Cornell, 1925-1931
A Cytological Demonstration of the Location of an Interchange Between Two Non-Homologous Chromosomes of Zea Mays (1930)
Letter from Barbara McClintock to Charles R. Burnham (December 16, 1929)
Box Number: 3
Folder Number: 4
Dec 7, 1929
Thanks for your letter and data. I am glad to have the counts, for as you know, I hate to repeat such counts as I am n.g.
For I am thru with seminar except for 2 more which come later. I rather enjoyed them although I did'nt [sic] get any research
done as you might think.
Dr. Sharp is up and around with out any assistance -- Walks to and from the lab. too.
As for finding trisomes in the [diagram]. I have'nt [sic] made a count as yet. Instead I have been planting corn -- have
planted over 8,000 kernels -- should'nt [sic] worry but what I have planted nearer 10,000. I am trying to sift down as
many trisomes as possible before planting time. We are going to have more room in the greenhouse this year. I shall be able
to do more than I had expected.
I have gotten good counts on b-lg chromosome. So far my LgLgLg male crossed with lglg female gives 1370 Lg: 626 lg. There
are many more counts that will be added in a few days.
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I have some more data on 3 strands or rather chromosome curser. Will enclose a copy of it. Rhoades is interested in this also
and is anxious to see the data. I have sent it on to him also. Rhoades has grown a generation in California -- more counts
etc. Not so bad!
Have you seen the papers on Malva -- Kristofferson, K.B. Hereditas 7. And on Galeopsis -- Muntzing. Hereditas 12: 297-319.
Species crosses gave F1 [diagram]. F2 gave [diagram] but with some gradations. Muntzing states cytology ok. I dont [sic] believe
it! His evidence is poor. He does'nt [sic] seem to grasp the type of cytological investigation needed, or rather does'nt
[sic] know good from bad. No figures are given -- merely statements --
Have you written your paper? You must get at it for Randolph is finding lots of recombinations and breaks etc. which may eat
into your line. Don't [sic] wait any longer! (Respectfully submitted, however)
I am glad you are going to the meetings. I am so poor I cant [sic] see Christmas presents even. I wrote an abstract for the
meetings concerning b-lg and r-golden chromosomes. Randolph is going and I suppose Eames. I don't know about the others.
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As for aceto-carmine -- I use 45 percent acetic. Boil and add carmine until saturated. Cool and filter. Use steel needles
-- that is all. For morph. I use the chloral. hydrate and aceto carmine
As for the slides -- I shall send you what I have -- which isn't much -- I can give you a good single ring. The ring of
6 we didn't work much with permanents. Have you any more material? The ring plus 1 -- I shall see what we have. -- So
much for A.M. It is now P.M. and I have had so many interruptions my work has'nt [sic] gone on -- neither has this letter.
I have looked over the slides -- low power only -- and don't see anything too unusual. I shall try oil when my scope is
free. Miss Besly and Mr. Hill are using it now so I haven't had any show with it.
After our great pains to clear you out and make room to stretch the body we have been recramped again. Mr. Scott has decended
[sic] upon us. We have done some more rearranging to squeeze him in. It was the only thing we could do. We have plenty of
(1 day later) -- I was interrupted again so am continuing in our next. Have gotten some more information from seedlings which
increases the no. of trisomes isolated -- as they stand it looks like this:
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starting from smallest: [diagram along left side of page] I have chr. 6 and 8 trisomic -- or in 2n plus 2 plants from which
I can isolate them. I hope to get number 2 from your [diagram] if no. 2 is involved. If c-sh-wx is number 4, I may have number
3 in some of my material. Number 10, or f-br. should come from Brink's [diagram]. I may have number 9 in one of my trisomes.
We ought to have a good share of them isolated by next summer, if, again, I will get to work. I have been unpardonably lazy!
Sharp and Emerson are trying to get me a job in the Graduate school, now. Other attempts were futile. From what Dr. Emerson
says I don't believe there is much of a chance. When you see Brink at Christmastime do your best for me and I will be
very grateful. I may be out of a job next fall. If Brink merely wants some one for next summer Hill may be ok by that time.
You might mention that also.
Beadle told me Lindstrom was going to give a talk on recent developments in corn. Dr. Emerson was asked to do it but turned
it over to Lindstrom but why? He does'nt [sic] know recent developments as Dr. Emerson himself realizes. I think it is
rather too bad.
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Let me know more dope -- on the work at Harvard. Is East reconciled to your continuing on corn? Do you see much of him? Do
you plan to come back this spring? -- all to be answered in your next, if that isnt [sic] before spring and here's hoping
the spirit moves you sooner than it did before --
As to the table on b-lg chr. 3 chr. crossing:
(1) Extra chrs. function thru pollen almost not at all.
(2) female equals 25 percent 2n plus 1 from 2n plus 1 crossed with 2n
3) Are we selecting cross over types among n gametes:
[diagram] and uni laggs and is left out. Therefore selecting crossover gametes, percent of crossover in b.c. not the percent
that took place
Therefore lg v4 equals direct index of crossing over between 2 strands. Others can be calculated from this -- As it stands
each strand retains the same x-over with every other as it did before approximately and the
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total no. of x-over gametes that function is increased. Double and triple crossover involving 2 and 3 strands not provided
So much for the news and notes --
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Reciprocal of above i.e. [diagram] Am making chr. counts on all for x-over calc.