CARNEGIE INSTITUTION OF WASHINGTON

DEPARTMENT OF GENETICS

COLD SPRING HARBOR, LONG ISLAND, N. Y.

March 29, 1955

Professor Joshua Lederberg
Department of Genetics

The University of Wisconsin
Madison 6, Wisconsin

Dear Joshua:

Of the material you requested, lysates of athB-6 and adD-11
are not available, and so we are sending you cultures.

We have quite interesting material on the position of loci
along the chromosome, For example, four tryptophane loci are all
linked together, and the order on the linkage map corresponds to
the sequence of biochemical blocks, A similar situation has been
found by Hartman for histidine loci, Unfortunately, the piece
carried by the phage must be fairly small, since we were able to
find only one case of linkage affecting different characters,

With best regards,

Sincerely yours,

MD:af Me. Demerec °