Brenner here reported results from his research with mutations of the phages (bacterial viruses) T2 and T4, research designed
to match a mutation in the fine structure of a phage gene to changes in a protein whose synthesis the virus triggered when
it infected a bacterial cell. Brenner sought to give experimental support to Crick's sequence hypothesis: that the sequence
of the bases in DNA specified the order of the amino acids in the polypeptide chain of proteins.
Item is handwritten.
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1959-03-24 (March 24, 1959)
Original Repository: Wellcome Library for the History and Understanding of Medicine. Francis Harry Compton Crick Papers
This letter contains very good news. I have now proved, by a rescue experiment, that the o gene controls the head protein.
What is more, the same experiment shows that the protein structure can be recombined and segregated and I think this is a
very important finding. The experiment was to cross T2o5UV x T4o5 and select for o5. Under these conditions, linkage is destroyed
to the following extent: Two markers (h and T) which in a normal cross would be found together in 80 percent of the R, now
only show 14 percent coincidence. Five rescued recombinants were picked, selecting for o5 and all had the T4 markers present
in original parent i.e. we crossed c plus h2 plus a5 r plus o5 times ch4 plus ar r or and all o5 were ch4tarr. Stocks were
grown and fingerprinted. Here are results so far: [diagram] Notice (1) recombinant nature of R stocks showing that differences
are not allelic (2) close linkage of peptide B to o5 (3) segregation of peptides A and D in R3.
There will be more data as we apply stains
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[BEGIN PAGE TWO]
I will confirm this using isotopes since A and B can be seen in I - D using phenylalanine -- we also have found the homologous
chymopeptides [?]. It looks as though my crazy idea is workable -- and I shall push on with it. Genetics going very well and
more mutants in o5 cluster. I am going to make a determined search for this part of protein.
Heard from Max about your Harvard job offers: I hope you don't succumb to the temptation. I have been offered one in Wisconsin
which has been or will be offered to you as well. Now that the Institute is on the way, I'm not keen to move.