CABLE ADDRESS ‘‘ RESEARCH"

IN YOUR REPLY PLEASE QUOTE

 

NATIONAL RESEARCH COUNCIL
CANADA

ATOMIC ENERGY PROJECT

CHALK RIVER. ONT.

January 18th, 1950.

Dr. Joshua Lederberg,
Dep rtment of Genetics,
University of Wisconsin,
Medison 6, Wisconsin.

De*r Joshu2,

Many thanks for the det2iled comments which you
have made on the manuscript. It will be 211 right for you to retain
the copy which you have. I %™ 9%t the moment deb®?ting whether to do
any further work or the possible 7llelism of sr and sd or to leAve it.
Probably I shall compromise bv doing 23n sr x sd cross in the 2bsence
of thitmin in the hope of réduéing the 2mount of p3rent#l growth and
thus perh#ps eliminating “ny ss prototrophs which might %rise from
parental mutants.

The peculiar beh°viour of the parent sd's (p2ge 7)
I attribute to their requiring some other substance (or subst2nces)
in addition to streptomycin.

The problem of "link?-e" between streptomycin response
and sug?r ferment?tions is something 2bout which I hope to write to you
in 2? month or so when Miss Nyholm's d°ta will be more ne?rly complete.

If there is loss within ° chromosome region one could think of it 2s
involving: (9) 8 portion or portions of v3ri7ble size 2nd position, or
(b) individu?l loci without reference to onetnother. In the case of

(a) it should be possible to establish 2 linear sequence on loss data
alone. Selection for 7 p%rticular locus (in this case sr) when mking
the cross greatly increases the ‘mount of d*t7, 2nd I %m hoping tht some
information c2n be obt2ined from this 4ppro4ch.

The reprint of your 1949 review ptper h7s just re2ched

me 3nd I am extremely gl7d to h7ve it, p?rticularly 2s delivery of the
volume in which it is published seems to have been deltyed.

Sincergly,

HBN:be How2rd Newcombe