A HIGH-RESOLUTION GENETIC-MAP OF THE NERVOUS LOCUS ON MOUSE-CHROMOSOME-8

The nervous (nr) mutant mouse displays two gross recessive traits: bot h an exaggeration of juvenile hyperactivity and a pronounced ataxia be come apparent during the third and fourth postnatal weeks. Using an in tersubspecific intercross, we have established a high-resolution map o f a segment of mouse Chromosome 8 that places the nr locus in a genomi c segment defined by D8Rck1 on the centromeric end and D8Mit3 on the t elomeric end. This map position places the nr locus within the BALB/cG r congenic region of the C3HeB/FeJ-nr strain, confirming the accuracy of our study. We used this map position to identify and evaluate three genes-ankyrin 1, cortexin, and farnesyltransferase-as candidates for the nr gene. These three genes were eliminated from consideration but allowed us to establish the conservation of synteny between the region containing the nr locus and a segment of the short arm of human chrom osome 8 (8p21-p11.2). Finally, the incomplete penetrance of the nr phe notype led us to perform a screen for modifier loci, and we present ev idence that such a nervous modifier locus may exist on mouse Chromosom e 5. (C) 1998 Academic Press.