Linkage mapping around the ragged (Ra) and wasted (wst) loci on distal mouse chromosome 2.

Mice that are heterozygous for the ragged (Ra) mutation, which is semidominant, have ragged coats caused by an absence of certain hair types. Ra/Ra homozygous mice usually die soon after birth, are naked, and have edema. Mice that are homozygous for the recessive mutation wasted (wst) appear normal until soon after weaning, but then develop tremors and ataxia, undergo atrophy of the thymus and spleen, and die by around 28 days of age. The Ra and wst loci map to distal mouse chromosome 2, but have never been positioned with respect to molecular markers. We have now mapped each of these genes in interspecific backcrosses that were also typed for available molecular markers. The results show that Ra maps very close to D2Mit74 and Acra-4, with no recombinants in 165 mice, whereas wst maps 3 cM distal to the most telomeric molecular marker on mouse chromosome 2, Acra-4.