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THE UNIVERSITY OF WISCONSIN

COLLEGE OF AGRICULTURE

Madison 6

ARTMENT OF GENETICS

February ll, 1948.

Dear dol-

Would bu be kind enough to send me sane yea&$ strains that I

may need for my work? I& requirements are of two types:

Firstly, I need some differential fermenters for a microbiological

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assay of enzyme-lactose mixtures, as a check on other methods. If you

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have strains with the following properties, I would appreciate transfers:

-r.

Secondly, I am getting a very bewildering picture on the genetic

control of lactose-enzymes in E. coli, There are several loci mutation

of which leads, specifically, to lac-; on the otheritand, there are a

number of mutations which block simultaneously the utilization of a few

sugars, with no rhyme or reason apparent as yet. E,a. maltose-,lactose-,
gluconate- (but glucose, galactose, pentose plus)! I would be interested
to look sometime for a swar bewilderment in yeast. ilhe genetic tests

would be much easier, since one need examine only the diploid heterozygote

to get a good line on allelism. You say that EbaB works with yea&$. Nould
you care to send two opposite mating type, dispersely growing haploids
that I could use for mutation-production? I'll send you whatever comes
out, of course. As for producing them, I've got that down to a T-- and

have accumulated, for example, about 50

mutations in coli.

Have you and Reiner formulated your

Best regards,

independent occurrences of Lac-

next-year 's plaas yet?

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