Narch 27, 1952

De. Verner Vo lane
4LL Bast & Strect
New York 21, Me¥.

Deer Voruer:

Thanks very much for cenldag owt the Waloman strain enc the polyauxe-
trephe. i've dens a few orecating testa wit, theiywith no vary conelusive
reau.te.

Firsts of cil, the Vaksuen oiradi io definttel; [4+ Cac ehowa hy transfer
of the Fs agent to 2-12 tootura}. I thtuk that there can bs Little further
. s 7 ed ey a
dount that te “lo and “1b sevles ave dortved Pro. Vale.

Tia Neko. strain ttcelf gave a negative rocult when teetedduich -1177 eto.
on stroptonyed: idnies? agur: 2% would have been Paseod ovary An our routine
SCTUURINEe progrict.

sindlaviy, da accord with earlier records and remarks, I d@¢ not find
evadence of crocclag cithsr between tho polysuiotroohs you previded, or
betWeod tha wad any Y+1l soctene (P+ art P-). Nowver, I tave also gone back
to n Pew oF tha cultwes labelled "14, fer exucpls "1+ ha-pl and Kit-Tri-h3,
These gave very apcradie results with 12 teators, and altogether only a very
few provowopyus were obtainad, so that I cannot go. ace $50 aku omphasis on
any negetive sosults. Tho "storilc" M1-Qt h cteok uae given uc vrototrophs with
Ked2 tauters, ail a very fos Cou wmicastel ty Wyakticant) wlth one or te non-
Kel2 teaters. Tiave ceubinations are far too oterile to bo of any use as such
for genetic atidies. All orocees vere done on winimc’ arar.iIn a few casos, the
payents Weve grown tozethor. at 37°.

There must he efmething that I'm overlooking, ant thnt vould make the
situation more hopeful. I cothered that you have obtained substantial ylelds
in crossse of f1t-- stocks X 58-161 and W677. Can you give me the deteaile
of your experinents that right help me to do the rane? The pant cultures that
IT now have are: Kit: h2thr; h2p2; h2oyet; har: hitr; telnt:p 44; pte; aot h2pl,
Kl: h2j; QTpi QTh; k&pk; trl; h2args I haven't tried all of these by any means,
and would appreofate any lead to help get them to croes with K12 testers.

Ave you having any luck with pant mutants in F-127
Sincerely,

Joehua Lederberg
Asroc