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Detroit Institute of Cancer Research

4811 JOHN R STREET
DETROIT 1, MICHIGAN

May 18, 195)

Dr. Joshua Lederberg

The University of Wisconsin
College of Agriculture
Department of Genetics
Madison 6, Wisconsin

Dear Josh:

I'm sending four paragons of the following genotypes:

108.3 a Pa Ad th bi py me g Ma mnt WY 2 S
168.4 qd pa Ad Th/th bi py Me/me g¢ Ma Yo
iy. 153.4e¥ Pa ad Th/th bi py gma Ih7 Thy 39

50.2a PaAdTh bipy ve G mt 37 flelays we0o

The designations refer to mating type, pantothenate, adenine,
thiamin, biotin, pyridoxine, melibiose, galactose and maltose. All of
these cultures grow well in synthetic medium supplemented only with the
growth factors indicated above. Thiamineless is not a satisfactory mark-
er, but pantothenate and adenine are good. I've included the pink ade-
nineless stock thinking that the color might be convenient. Some of
these segregants were not tested for characters which were heterozygous
in the cross, e.g. 168. for melibiose and thiamin. I have pedigrees
for each of these stocks back to the original parents which came from
the Lindegrens. As you know, their stocks are primarily S. cerevisiae
into which various fermentative characters were introduced by crosses
with other species, e.g. melibiose fermentation was introduced from S.
carlesbergensis. ~

These cultures have been selected on the basis of genotype .
and non-clumping. We have generally had no difficulty with illegitimate
diploidization or with lack of cross-fertility or poor growth. There is
some variation in the intensity of the cytochrome bands anong our cul-
tures, but we do not have quantitative data on oxidative capacity on
very many cultures. I gave vreference to non-clumping in selecting these
because I thought this would be most important in your work,

Thanks for calling my attention to the Laskowski paper. Kohrus-
Si. told me it was coming out, but I had not seen it.

With regards to you and Esther.

6. .

Caroline Haut
CRimv Research Associate