UNIVERSITY OF WASHINGTON
SEATTLE 5, WASHINGTON

March 16, 1956

Dear Dr. Lederberg:

I've held off sending you the material you requested in
your letter of February 27 until I could send you a
manuscript dealing with some problems arising out of
red yeast. The ms is going to you under separate cover
and may be of some help to Mr. Wright though I don't know
what your difficulties are and they may not be at all
related to what we've found here. The strains we are
sending you have the ad2 of Ephrussi and are dominant at
the other nutritutional loci. I could send you, if you
wish, strains carrying ad2 in combination with other
nutritional defétiencies if you should wish to set up
crosses by the prototrophic technique.

The segregational petite needs more work done on it.
Ephrussi's material also shows an instability toward
vegetative petiteness. So did Caroline Raut's mutant

some years ago. However, it's hard to find haploid

strains which do not throw a relatively high number of
petites and I can't guarantee the stability of the material
I'm sending you.

The strains we are sending today are:

42355D: of ad2
42400: a ad2

I would like very much to visit you in Madison and will
do so when the first opportunity arises.

With best regards,

Herschel Roman