UNIVERSITY OF COLORADO
MEDICAL CENTER Maré
4200 EAST NINTH AVENUE (oe

DENVER 20, COLORADO
DEPARTMENT OF BIGPHYSIGg

COLORADO GENERAL HOSPITAL
COLORADO FSYCHOPATHIC HOSPITAL

SCHOOL OF MEDICINE

January 28,1959

Professor J. Lederberg
Department of Genetics
stanford University
Stangford, Cal.

Dear Joshua and Esther:

Enclosed find a copy of the MS that I would like you to send fo the

PNAS, subject to your approval. If you will return it with your comments,

if any, to me I will send the final form required by the Froceedings. You
might also advise me of what type of letter is required of me to assure that

I am bearing the costs of publication. Since I have not had any contact

with the Proceedings before I am completely in the dark with regard to what is
needed .

I received some reprints of abstracts, etc., from the Madison department

(I belgieve). The reprint of Ethets Montreal paper remined me that I would like
to have a Gummary of what has ‘been done with re d to the position effect
studies among the various’Gal's, such as combinations actually studied, missing
ones, HFT stocks made and etc., that I will not duplicate very much material.
Since the world seems cistron happy these days I beieve that we shpuld get

out all the material available. I still think that quantitative enzyme assays
are needed, but we tay as well go ahead and publish the preliminary information
to that. If the plans go through here, I may have a new lab(s) by the fall and
the bfiochemist who is joining us is interbAted in working with me on the
problem and we shpuld have some good material eventually. My parts of the
cis-trans bussiness you will hear of shortly.

I have been rounding out a few points on other aspects, the only one of which
you may not know is that XEXXXHMKAR XE HH¥XEXTRHX spontaneous lambda has very
low transducing activity. This was found by Gal,- 77x, Gal “ Gal,” using a large
number of lysates ( 40-50 srontaeous ave. about X®% 10°-10 plaques per mi.

I have obtained E¥KX three segregating clones and about 32 stable Gal’. I doubt
that mutation can be of concern here. This means for sure that homogenotes

could be formed spontaneously in a strein which adsorbed it own rhage. T have
not seen any as yet and will probably not try much longer since it is not an

important point.

I am also looking for a marker near Gal to use in putting things in order. I
have a bunch of AA analogues which may legnd themselves to easy screening.
Thought that I would put resistance in Hr Gal+, cross on MGal and score Gal+
be replication to analogue agar. Crude, but not requiring very much effort. I
am also looking for Gal dependence, which could be worked out in minimal

with venicillin and replica plating. If you have had any experience with any
of these I would avpreciate hearing of it.

Recently Cornell has approached me regarding Zelle's place which is now vacant,

It appears good on paper, have you heard or know of any alate ?

Moog you couth st iy wih sus, ME Ger