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, w e report here the genetic mapping of the nb locus with respect to Chromosom e 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 interva l of 1.6 cM on mouse Chromosome 19 defined by flanking markers D19Mit11 and D19Mit53/D19Mit27, and identified a tightly linked polymorphic marker, D19 Mit67, that co-segregates with the mutation in the backcross progeny examin ed. This places nb locus 4 cM distal to its present position as indicated i n Mouse Genome Database at The Jackson Laboratory. We have also mapped a ye ast artificial chromosome (YAC) contig in this locus interval which suggest s the ab interval to be less than one megabase of DNA.