Letter from Charles R. Burnham to Barbara McClintock
Burnham, an old friend of McClintock's, wrote to her shortly after she returned from her trip to receive the Nobel Prize.
He briefly discussed some recent research on segregation from chain configuration in pearl millet. Attached to this brief
letter is a six-page recollection of his fifty-five year association with McClintock.
Item is handwritten.
Number of Image Pages:
7 (922,359 Bytes)
1984-03-18 (March 18, 1984)
Burnham, Charles R.
Original Repository: American Philosophical Society. Library. Barbara McClintock 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
Box Number: 1
Folder Number: 6
Dr. Barbara McClintock,
Dept. of Genetics,
Cold Spring Harbor Lab,
P.O. Box 100, Cold Spring Harbor, N.Y. 11724
1539 Branston St.
St. Paul, Minn.
55108, Mar 18, 1984
When you find time, tell me about your trip to receive the Nobel Prize, events there, etc. You were competing in the press
with the Peace Prize given to Wolenza (his wife to receive it). I have a grad student living here, a Ph.D. student in Soils
(Peat studies). His mother sent a clipping from the local paper in Mankato -- it had a short account on your talk.
The past few days I have been reviewing a paper by Kodorra, Andhra, Univ. Waltair, India, -- on segregation from chain configurations
in three translocations in Pearl Millet, one of [diagram] [line to, pairing always fails in arm a] which always forms chains.
He has an earlier paper in genetic Res. 34:69-76 1979 which [line to, nothing about behavior of chains] I must read.
At any rate, he had convincing evidence (metaphase-1 observations, spore quartets) that the kinds of segregation depend on
which arm of the pachytene cross fails to remain associated (or fails to pair):
In the [scientific symbol]4 configuration, the four kinds of segregation occur (may occur) in meiocytes that dont [sic] crossover
in interstitial segments: alternates 1, -2, adj.-1 -2. If failure to be paired occurs in arm b or d, only alternate-1 and
adjacent-1 occur. If pairing fails in arms a or c. (the centric, non-translocation arms, only alternate-2 and adjacent-2 occur.
The ones I have studied in corn are all of the type with failure in arms b or d to form the chains. Phillips and I will try
to select the other type for work this summer. What follows are some personal recollections.
Sincerely Charlie B.
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Mar. 18, 1984
These are memories that involve the two of us, I hope you dont [sic] mind.
Do you remember when I first met you in the cornfield -- was it on a Sunday? [mark to note, 55 years ago this June.] Seed
I had sent had been planted, and I went to the field to see it. Together we located the plants and figured out the planting
I had read your note in Science on the corn chromosomes. I had taken all the courses in Botany except taxonomy and the lab
in cytology (Allen). One of the courses with C.E. Allen was "Facts and Theories of Heredity, in addition to his lectures
My material obviously needed some cytology. You set up another small table at the end of a partition (wall divider?) -- almost
opposite where you were working. I was struggling to make slides in which I could see the chromosomes. You were continually
showing me what you were getting -- chromosomes clearly showing what you said was there. Finally I did get slides in which
I could count the chromosomes (also) and could do it repeatedly. I dont [sic] remember, but I must have followed your instructions
and had taken sporocyte samples from my material. When tassels began to shed pollen, I began classifying the plants for sterility
and also for Wx-wx -- you found how to get good classification for Wx vs wx pollen with the I2-KI stain -- cut off the light
from below the microscope stage. I had stumbled on to it, but hadn't known what I had done to get the good classification.
I tabulated the results on a movable blackboard in the room and It was soon evident that in one group there was a ratio of
1N:2-semisterile: 1 high sterile with a few having intermediate amounts of pollen abortion. When I looked at sporocytes from
the high-sterile there were 2 [scientific symbol]4. Also there was a linkage between wx and sterility. Brink and I were using
a prax stock as a standard normal -- also that stock had the large terminal knob on 95 -- what luck!
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Mar. 18, 1984
Tabulations from another group showed nearly all plants were semisterile, with a few having low sterility. After I found the
2 [scientific symbol]4 for the other group, I began to try to find an explanation for the other result. One night it suddenly
dawned on me that if one chromosome were involved in the two, there would be a [scientific symbol]6 in the high steriles (3II).
I went to the lab early the next morning and I believe had a slide showing it when others came in. That is the way I remember
it -- do you remember that? It was a great thrill for me.
You were getting results from the trisomies, cytology and genetic segregations. Others were getting results: linkages, etc.,
sharing information and pollen from stocks to make crosses needed to make further tests, etc. Beadle was doing cytology on
male steriles. For one of them, it was quite a while before I realized that one that he was talking about was not A-synaptic,
something to do with the A alenrone factor, but a lack of synapsis. As I was working at my microscope, it suddenly hit me
-- and I blurted out the explanation --realization as to what it was, you commented in such a way, that I realized another
had drawn conclusions about me from my previous confusion. Personal: Do you remember this occasion: As I worked along at my
microscope and you continued to show me what you were finding, on one occasion I was overcome with emotion -- obvious to you,
and your response was "oh!"[?]. Nothing more was said at the time. That night I did a lot of thinking and decided
to "cool it" -- I didn't want to jeopardize our friendship. Maybe that is why we have been able to continue our
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Do you remember when during corn pollination I had one of my annual stomach upsets and went over to a tree on the north side
of the field and laid down under the shade? You came over to talk with me. I think we shared ideas and information all summer.
Then I went to the Bussey Institution for the winter, back to Cornell for the next summer, then to Cal Tech. Was that the
summer Marcus came back from Cal Tech? Just before I left on my trip, I went with Harriet on a short farewell drive. When
I returned, you asked her "Did you tell him?" She replied "No". Then you and I went for a short drive. I was
so excited about going on the trip and to Cal. Tech, very little else registered. Also, the job situation was such that I
could offer no security. Attitudes then were different from what they became later.
Those were exciting times: linkage groups being associated with chromosomes -- your work, pachytene analysis of my 8-9a (your
work), Harriet's and your paper on cytological proof that genetic crossovers were correlated with cytological exchanges.
It was one of my stocks that made part of the results not as clear cut as they might have been. I had had trouble getting
plants from cshwx stocks, and had supplemented them with cshWx seeds -- plants from these latter seeds were one source of
Then you came to Cal Tech while I was there. I was working with a low-sterile stock, showed you some slides. You came back
the next day with your analysis [mark to note, I still have your sketches]. I was a little "taken aback" at first
-- you noticed it from what you told Andy -- but my reaction soon passed off, as I realized the intensity of your interest
and ability to interpret what you saw under the microscope.
When I was asked about teaching a course in cytological technique, you made suggestions on what to do. In that class, during
the period when the smear technique was the exercise, every student was
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able to get a slide in which he had cells good enough to get the chromosome count -- the only time it ever happened for me.
The Morgans (T.H. and L.V.) invited us to their home. Another episode: One of the men invited me to a party -- when I arrived,
he asked about my wife -- he had thought he was inviting Beadle. I did not respond as I should have to ease his feelings --
I never did develop any of the social graces -- as you well know.
Then I went to Missouri -- some work on pachytenes of sorghum versicolor -- only 5 chromosome pairs, but I never did get a
spread where all the chromosomes could be followed. I tried taking sporocytes at different times during the day, and at night
-- no luck. You came there -- was it to work on the deficiencies for various gene markers -- result: the Mo. Bulletin? I dont
[sic] remember what I was doing on corn -- it might have been the pollen abortion transmission studies, along with more on
interchanges. I remember Stadler saying that there probably was a simple trick to building the big ring -- I came close, but
it remained for a student of mine, Inman, to find the trick -- The basis for his thesis and what I describe in my book as
the Inman scheme: crosses between parents that have the same interchange or interchanges in common but involving in each parent
an additional chromosome. Each step produces 2 [scientific symbol]4, no sterility higher than that. I have tried to omit some
intermediate steps, but crossovers that break down the rings give problems. Inman's scheme avoids that but for 10II, it
is a long process. I am still working on that. It ends up with one stock with all the interchanges necessary, so that it crossed
with N equals a [scientific symbol]20.
I remember one evening you, Stadler, and I were coming back from some event -- I left (was it on a bus? -- and the next day
you asked why I had left -- my response was "three is a crowd".
Sometime that fall I went back to Cornell. Emerson gave me the job of calculating and checking the recombination values for
their "linkage summary". Also, I helped several Chinese students with their theses. I believe that might have been
when Emerson, Beadle and I went to visit Eyster (Bucknell Univ.) -- He showed us his work, a tremendous am't of linkage
data with new traits on cards. He promised to furnish stocks
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I dont [sic] remember if he gave us his stocks then or sent them to Emerson later. We visited him because he usually failed
to send stocks. He had sent his brown midrib stock to me in response to my request. I had happened to make a cross that involved
pr and bt -- my first finding of a linkage -- exciting for me.
Dr. Reddick at Cornell had a problem that involved crosses between Solanum demissum and S. tuberosum. I had applied for a
Sterling fellowship at Yale Univ., but also applied for work with Reddick. Both were awarded, but I went to Yale. While there
a job at West Va. opened, and I obtained that job -- it involved teaching an Advanced course in genetics and cytogenetics,
breeding work with corn, field corn breeding and Stewart's wilt disease resistance in sweet corn; watermelon wilt disease
(crossed with the Russian wilt resistant species), and winter barley. I could also continue my corn cytogenetics. There I
met a woman from Mo., and we were married. A job at Davis, Calif. opened up. I was offered the job, accepted, but after a
few weeks, I received a telegram that the appointment was not approved -- no explanation, even! I had not resigned at West
Va., continued there until 1938, when I came to Minn.
I believe you came to Minn. once for a visit and called on my wife. She didn't say anything specific, but I had the impression
that you wanted to assure yourself that my situation was O.K. My wife was good at understanding people and getting their cooperation.
As I look back on my married life, I realize my wife was very tolerant -- she must have been to put up with some of the things
I did.-- There was never any interference with my work, and she was free to participate in whatever activities she wished:
League of Women Voters, Faculty Women's Clubs[?] etc., also various activities for our daughters.
Oh, yes, when I was at Mo., Stadler was planning to attend the Genetics Congress at Ithaca. I planned to drive -- Luther Smith
and another student plus Stadler. Stadler had to have more time to finish his paper -- we started late and arrived at Ithaca
about noon on the opening day, after driving all night.
Where were the meetings at which you and I had material at a poster session? I believe I had tabulated the number of breakpoints
per chromosome based on the interchanges we had. I remember R.A. Fisher commented that the numbers fitted a Poisson distribution.
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pushed me to talk to people as they came in.
We were both at the Xmas meetings; AAAS, in New York. Ibrahim, one of my students was with me. You hadn't had a chance
to talk to me about your work with the Ac-Ds system, but came with us to the train station and went through the whole story.
When we left on the train, my student and I immediately wrote what we remembered from what you told us. There were some questions;
so I wrote to you and you answered them. I included that in the mimeographed material that I used as hand-outs in my Advanced
Genetics and cytogenetics courses here.
When Ron Phillips was at Cornell on a Post-Doc Fellowship, I was invited there to give some seminars. Again, we had chances
to talk -- then your visit to Minn: seminars, sessions with grad students, discussion of ears that Ron had showing Ac-Ds effects
-- your comments were taped.
Then I attended the Stadler symposium at Mo., the one at which you gave a talk -- very warm greetings again-- I attended their
evening banquet -- we should have spent it talking, since you were not planning to attend -- I had not realized you were not
planning to attend.
The next occasion was the Maize Breeding, Illinois meeting at which we had several opportunities and interesting exchanges.
I remember you told me about all the party finery -- : clothes, shoes, etc. you were discarding -- signals?
Our talks at the July, 1982 celebration of the 75th Anniversary of the Synapsis Club at Ithaca, again, were warm and friendly.
I know that they were and are mutual. I would like very much to have the chance, again, to talk. Is there any possibility
that you would be interested in spending a little time here this summer? Phillips and his group are doing some very exciting
things, also Rubenstein, Messing and their group. I believe Messing talked with you recently.
We obtained second backcross to American of Chinese crossed with American chestnuts last summer (300 plus) I say we -- but
others made the crosses, and hopes are to get more this year. I have been frank with you. I have appreciated all the support
you have given me over the years.