ot October 7, 1955
ov

Dr. Sofia Simmonds

Department of Biochemistry

Yale University

New Haven, Connecticut

Dear Topsy:

We will be happy to send you #-1975 and 1977 again. The cultures(to follow)
are directly put @f lyophil (having been put away in May 1952.) In fact, it
would save us a mild chore if you could send back two or three lyophil tubes
of them, since you are putting them away again yourself.

Actually, these are Fsther's isolates, but as you know, we make a point
to stick to Genetics, and are pleased to leave the chemistry to others.

Did we not send you W-1976 previously? i+-1975 and W-1977 are one=-step mitants;
W-1976 is recorded as a serine (not~glycine auxotroph) that was obtained from
W1975, in a second step, in the course of 4 hunt for further mtations (on
glycine-minimal). We haven't atudied it genetically to learn whether there are
two loci; probably it would not be too difficult to cross #-1976 by, say,

"m6 S¥ or W-1177, on miniml+amglyeine, and replicate to minimal to see if any
of the recombinants respond to glycine. But thet's another problem.

We hope you will remember to send us reprints of your papers on these mtants,
The latest we have now are about 1950.

Sinceraly,

-

lat tt gimme
Pris Lederberg

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