Mapping of the gracile axonal dystrophy (gad) gene to a region between D5Mit197 and D5Mit113 on proximal mouse chromosome 5.

The gracile axonal dystrophy (gad) mouse, which shows hereditary sensory ataxia and motor paresis, has been morphologically characterized by the dying back type of axonal degeneration in the nerve terminals of dorsal root ganglion cells and motor neurons. In the present study, using an intraspecific backcross between gad and C57BL/6J mice, the gracile axonal dystrophy (gad) gene was mapped to a region between D5Mit197 and D5Mit113. Estimated distances between gad and D5Mit197 and between gad and D5Mit113 are 0.4 +/- 0.3 and 5.0 +/- 1.0 cM, respectively. The gene order was defined: centromere-D5Mit81-D5Mit233-D5Mit184/D5Mit254- D5Mit256-D5Mit197-gad-D5Mit113-D5Mit7. The mouse map location of the gad locus appears to be in a region homologous to human 4p15-p16. Our present data suggest that the nearest flanking marker D5Mit197 provides a useful anchor for the isolation of the gad gene in a yeast artificial chromosome contig.