THE GERM-CELL DEFICIENT LOCUS MAPS TO MOUSE CHROMOSOME 11A2-3

The autosomal recessive mouse mutation, germ cell deficient, gcd, mani fests as infertility in both sexes owing to improper migration and/or proliferation of primordial germ cells during embryonic development. M ice harboring this mutation have been hypothesized to be animal models of the human syndromes, premature ovarian failure and Sertoli cell on ly syndrome. Since the gcd mutation arose from the insertion of over 1 00 kb of foreign DNA into the chromosome during a transgenic mouse exp eriment, fluorescent in situ hybridization with the transgene as a pro be was used to determine the chromosomal position of the gcd locus. DA PI chromosomal banding in conjunction with double labeling with the al pha 1(I) collagen gene revealed that the gcd locus is situated on mous e Chromosome (Chr) 11A2-3. Two candidate genes, Lif and Oncostatin M, map near the gcd locus; however, Southern blot hybridization analysis revealed no gross rearrangements in these genes in gcd mice. The chrom osomal position of the gcd locus will prove valuable in the search for other candidate genes as well as a landmark for positional cloning ex periments.