A MUTATION IN THE TER GENE CAUSING INCREASED SUSCEPTIBILITY TO TESTICULAR TERATOMAS MAPS TO MOUSE CHROMOSOME-18

Little is known about inherited susceptibility to spontaneous germ cel ls tumours in humans or other species. The Ter mutation in laboratory mice is novel in that it acts codominantly to reduce germ cell numbers on many inbred strain backgrounds and to enhance dramatically inherit ed predisposition to spontaneous testicular teratocarcinomas in strain 129 inbred mice. We have adopted a PCR-based, DNA pooling method for mice with 'extreme' phenotypes (small testes versus normal-sized teste s) to identify a candidate linkage to the Ter locus. Two independent m apping approaches confirmed this evidence for Ter linkage near D18Mit6 2 on mouse chromosome 18, and suggest a possible human homologue on ch romosome 5q.