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The Francis Crick Papers

Letter from Andre Lwoff, Institut Pasteur (France) to Francis Crick pdf (124,160 Bytes) transcript of pdf
Letter from Andre Lwoff, Institut Pasteur (France) to Francis Crick
In this letter Lwoff raised the problem that the two chains of the double helix had a different base sequence because they were complementary (and not identical), which meant that if each chain individually coded for proteins, the proteins would be different from one another.
Number of Image Pages:
2 (124,160 Bytes)
1957-09-13 (September 13, 1957)
Lwoff, Andre
Institut Pasteur (France)
Crick, Francis
Original Repository: Wellcome Library for the History and Understanding of Medicine. Francis Harry Compton Crick Papers
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Reproduced with permission of the Institut Pasteur Service des Archives.
Medical Subject Headings (MeSH):
Genetic Code
Exhibit Category:
Defining the Genetic Coding Problem, 1954-1957
Metadata Record Letter from Francis Crick to Andre Lwoff, Institut Pasteur (France) (September 25, 1957) pdf (189,408 Bytes) transcript of pdf
Box Number: 10
Folder Number: PP/CRI/D/1/1/12
Unique Identifier:
Document Type:
Letters (correspondence)
Physical Condition:
Series: Correspondence
SubSeries: Alphabetical Correspondence
SubSubSeries: Correspondence 1
Folder: Correspondence L
Paris, le 13 septembre 1957
Dear Crick,
I have just read your paper with Griffith and Orgel in the P.N.A.S. and Brenner's one in the same journal. One thing is for me difficult to understand. Let us consider the four bases A, B, C, D in which A-C and B-D are complementary.
Let us now consider a sequence of triplets in helix 1 and the complementary sequence in helix 2.
Unless it is assumed that A = C and B = D, which is an impossible hypothesis, it is clear that
ABC is different from CDA and ADC
DAC is different from BCA and ACB
BDA is different from DBC and CBD
If this is true and we assume that each single helix 1 and 2 organizes one molecule of protein, then a double helix would produce two different protein molecules. This seems unlikely.
I see two ways out possibilities : a) the two sequences formed on helix 1 and 2 get stuck and thus forme a molecule ; b) each amino acid is taken care by three bases, one of which is located on one helix, the other two on the other.
For esthetical reasons, b seems more likely than a. It is satisfactory to visualize the double helix functioning as a whole when directing syntheses. As a matter of fact, it is probably why a double helix exists. Otherwise, a single helix 1 would produce a complementary helix 2. One organism would inherit helix 1 and the other helix 2, and each one would produce different protein molecules.
I am somewhat worried because either this could be completely idiotic or very interesting, or perhaps very well known, and I would be grateful if you could clarify the situation for me.
Sincerely yours,
Andre Lwoff
A. Lwoff
P.S. I apologize for the bad state of this letter, but I have no possibility to have it retyped.
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