High resolution genetic and physical mapping of the mouse asebia locus: A key gene locus for sebaceous gland differentiation

The asebia (ab) mutation in the mouse is an autosomal recessive trait with hypoplastic sebaceous glands. As a first step toward cloning the nb gene, we report here the genetic mapping of the nb locus with respect to Chromosome 19 microsatellite markers. 644 backcross progeny were generated by mating (CAST/EiJ x DBA/1LacJ-ab(2J)/ab(2J)) F-1 heterozygous females and parental ab(2J)/ab(2J) mutant males. Our results located the rib gene to an interval of 1.6 cM on mouse Chromosome 19 defined by flanking markers D19Mit11 and D19Mit53/D19Mit27, and identified a tightly linked polymorphic marker, D19Mit67, that co-segregates with the mutation in the backcross progeny examined. This places nb locus 4 cM distal to its present position as indicated in Mouse Genome Database at The Jackson Laboratory. We have also mapped a yeast artificial chromosome (YAC) contig in this locus interval which suggests the ab interval to be less than one megabase of DNA.