Skip to main contentU.S. National Library of MedicineU.S. National Library of Medicine


Profiles in Science
   
Pinterest badge Follow Profiles in Science on Pinterest!

The Barbara McClintock Papers

Title:
Letter from Barbara McClintock to Charles R. Burnham pdf (196,898 Bytes) transcript of pdf
Letter from Barbara McClintock to Charles R. Burnham
Description:
This letter to Burnham related some of the findings that possibly informed McClintock's 1930 article in "Proceedings of the National Academy of Sciences" on semisterility in maize. Contains data and illustrations.
Item is handwritten. Item is a photocopy.
Number of Image Pages:
4 (196,898 Bytes)
Date:
1930-04-07 (April 7, 1930)
Creator:
McClintock, Barbara
Recipient:
Burnham, Charles R.
Source:
Original Repository: University of Minnesota, University Archives. Charles Burnham Papers
Rights:
Reproduced with permission of the University of Minnesota, University Archives. Charles Burnham Papers
Subject:
Medical Subject Headings (MeSH):
Chromosomes
Genetics
Exhibit Category:
Education and Research at Cornell, 1925-1931
Relation:
Metadata Record A Cytological Demonstration of the Location of an Interchange Between Two Non-Homologous Chromosomes of Zea Mays (1930) pdf (478,157 Bytes) ocr (12,563 Bytes)
/ps/access/LLBBBW.pdf
Box Number: 3
Folder Number: 5
Unique Identifier:
LLBBNZ
Document Type:
Letters (correspondence)
Language:
English
Format:
application/pdf
image/tif
Physical Condition:
Good
Transcript:
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]
[END PAGE ONE]
[BEGIN PAGE TWO]
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.
[END PAGE TWO]
[BEGIN PAGE THREE]
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]
[END PAGE THREE]
[BEGIN PAGE FOUR]
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.
Metadata Last Modified Date:
2006-08-28
Linked Data:
RDF/XML     JSON     JSON-LD     N3/Turtle     N-Triples