PHYSICAL AND GENETIC MAPS OF THE DEAFWADDLER REGION ON DISTAL MOUSE CHR-6

The deafwaddler (dfw) mutation, displaying motor ataxia and profound d eafness, arose spontaneously in a C3H/HeJ colony and was mapped previo usly to distal mouse Chr 6. In this study, a high-resolution genetic m ap was generated by positioning 10 microsatellite markers and 5 known genes on a 968-meioses intersubspecific backcross segregating for dfw, [(CAST/Ei-+/+ x C3HeB/ FeJ-dfw/dfw) x C3HeB/FeJ-dfw/dfw], giving the following marker order and sex-averaged distances: D6Mit64-(0.10 + 0.1 0 cM)-Pang-(1.24 + 0.36 cM)-Itpr1-(0.62 + 0.25 cM)-D6Mit108-(0.52 + 0. 23 cM)-D6Mit54-(0.21 + 0.15 cM)-D6Mit23, D6Mit107, D6Mit328-(0.72 + 0. 27 cM)-D6Mit11-(0.21 + 0.15 cM)-dfw-(0.93 + 0.31 cM)-Gat4, D6Mit55-(0. 10 + 0.10 cM)-D6Mit63-(0.31 + 0.18 cM)-Syn2-(0.62 + 0.25 cM)-D6Mit44 ( Rho). Female and male genetic maps are similar immediately surrounding the dfw locus, but show marked differences in other areas. A yeast ar tificial chromosome-based physical map suggests that the closest marke rs flanking the dfw, locus, D6Mit11 (proximal) and Gat4, D6Mit55 (dist al), are contained within 650-950 kb, The human homologues of the flan king loci Itpr1 (proximal) and Syn2 (distal) map to chromosome 3p25-p2 6, suggesting that the human homologue of the dfw, gene is located wit hin this same region. (C) 1998 Academic Press.