THE GENETIC-MAP AROUND THE TAIL KINKS (TK) LOCUS ON MOUSE CHROMOSOME-9

Tail kinks (tk) is a classical mouse skeletal mutation, located on Chr omosome (Chr) 9. As the first step for the positional cloning of the t k gene, we have established a genetic map of a region surrounding the tk locus by generating a backcross segregating for tk. From this backc ross, 1004 progeny were analyzed for the coat-color phenotype of the p roximally located dilute (d) gene and for the distally flanking micros atellite marker, D9Mit12. Fifty-six recombinants between d and tk and 75 recombinants between tk and D9Mit12 were identified, completing a p anel of 130 recombinants including one double recombinant. This panel allowed us to map five microsatellite loci as well as d and Mod-1 with respect to tk. We show that one of the microsatellite markers mapped, D9Mit9, does not recombine at all with tk in our backcross. This indi cates that the D9Mit9 locus will serve as a good starting point for a chromosomal walk to the tk gene.