Letter from Barbara McClintock to Charles R. Burnham
McClintock appeared excited about her research and an upcoming trip to California for her NRC fellowship at Caltech. Contains
data and numerous diagrams.
Item is handwritten. Item is a photocopy.
Number of Image Pages:
6 (424,901 Bytes)
1931-07-30 (July 30, 1931)
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):
From Ithaca to Berlin and Back Again, 1931-1935
Letter from Barbara McClintock to Charles R. Burnham (August 8, 1931)
Box Number: 3
Folder Number: 4
[written on top margin in same handwriting, Morgan wrote me asking if I could bring my own microscope. Sharp thinks Morgan
should have some more obtained for use there. What is the financial situation? Can they afford to buy any? Sharp isn't
for my taking one from Cornell. Could you let me know -- ask Sterling.
Take a week off to read this letter]
July 30, 1931
Your letter just came. I was delighted with all the news. It shows great progress. I have been on the verge of writing you
to tell you what I have been doing and felt you would like to know.
I was especially pleased about the [scientific formula]. Have you seen where the interchanges occurred? I think number 7 will
be an easy one for prophase as I believe it has a sharp dark marker near the insertion region. I have'nt [sic] checked
this but will this winter. You can find which part gives the peculiar number 7 trisome appearance.
Also -- japonid -- a great find. One of the earliest known genes and no place for it. It would be nice to have it on number
8. Will you make the cross? I have not crossed V1 to M plus long interchange chr. of [scientific formula].
Am interested in the translocation involving the satellite chromosome. Have you found the position?
[END PAGE ONE]
[BEGIN PAGE TWO]
Have sent the paper on e-sb-u4 genes in to the proceedings. Thanks for your P.S. in your letter. I still feel guilty about
Concerning my work this summer -- Several interesting points. I don't know whether to begin chronologically or jump into
the middle -- First -- I think I have some of the "B" type chromosomes of Randolph's solved. I ran into it by
chance in some of Stadler's material and didn't recognize all there was until I had some of the story. The chromosome
is very peculiar, unlike any other prophase chromosome. It is almost entirely pynotic -- hardly like the knob region but not
chromomeres. It looks like this in prophase -- [diagram] When 2 are present they usually synapse together along their length
to form a double structure as above but may synapse with itself; doubled around on itself. That is the reason Randolph found
some figures with 10" and 2 univalents instead of 11". When 3 "B" types are present the synopsis is just great!
[END PAGE TWO]
[BEGIN PAGE THREE]
It forms most peculiar figures but none unexpected on basis of my interpretation. The most frequent is a [diagram] form which
puzzled me considerably when I started for I saw this in a 23 chromosome plant first. [diagram] very occassionally [sic](=seldom)
in prophase a straight univalent is formed (21 chr. plant) but more frequently [diagram] only close synapsis, not a v. When
3 are present in one plant get three varieties in prophase [diagram]
[END PAGE THREE]
[BEGIN PAGE FOUR]
The 2nd -- I looked at some [scientific formula] prophases to see about the chr. involved in [scientific formula] to check
on Ly and f-br. size. Wanted to get morphological slope for trisomes. Report of Cooper's and Brinks' was not complete
enough. I found the break occurred at long arm of satellite chromosome (about region of pl gene, see below) and just below
insertion region on long arm of, I believe, the f-br. chromosome. What is the dope on this chr.? It looks to me as if the
longest chromosome were involved -- i.e., f-br and not b-lg. The one figure I had was beautiful. All the other chr. in the
cell were very good except 2 which I could make out partly. It still looked like the longer. Morphologically (i.e. size of
arms) this figure fitted with f-br. much better than b-ly. Breaks occurred about [diagram]. If this turns out to be f-br,
morphology for this chr. is ON.
[END PAGE FOUR]
[BEGIN PAGE FIVE]
which was the right size and morphology for the f-lg chr. It had a peculiar marker near the insertion region which allowed
me to spot the chromosome in this culture. Prophase figure looked like this: [diagram] A record ly plant in related culture
had same chr. involved only a shorter sequencing. [diagram] Normal Ly plants had no loss in this chromosome. B is probably
on the long arm near the knob. I am just working it out now.
Now for pl -- In a similar way Pl female crossed with pl male, x rayed embryo, picked out pl plants. Found one which showed
a deficiency of about 1/2 the long arm. Therefore pl was in the lower part of long arm of satellite chromosome. Found a 2nd
plant that was pl. It showed an interchange between satellite chr. and another chr. (number 7 possibly or number 5) which
curves at about the same position as in [scientific formula] -- i.e., just above the knob on long arm region. If pl was knocked
out or injured in the interchange there should be
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[BEGIN PAGE SIX]
[written on top margin in same handwriting, Didn't finish my last of topics I had made out but this letter got too lengthy
as it is. I won't blame you for not trying it all at once.]
no crossing over between pl and interchanges for pl is probably at interchange point. One other pl plant was examined. It
showed no visible alteration. We shall test it for a non-visible deficiency or mutation.
So much for the major part of the summer work. I am looking over a number of defective plants and find many types of alterations.
Want to attack the so-called recoveries of Stadler's. In plant characters they are very infrequent.
Dr. Parker and Harriet drove out here in my Ford, I had left it in Ithaca. They thought I needed it and drove it out to me.
I was delighted to see them for the associates here, except for Stadler, have not been exciting at all. It is a one-man show
on his part.
The summer here has been hot and no rain. The plants suffer. The methods of irrigation are different and costly.
Heard the news of Marion and Beadle thru Harriet via Rhoades from Emerson who had directly from Beadle.
If anything turns up of particular interest I shall let you know--