| First Author | Beechey CV | Year | 1994 |
| Journal | Mouse Genome | Volume | 92 |
| Issue | 3 | Pages | 502 |
| Mgi Jnum | J:20782 | Mgi Id | MGI:68852 |
| Citation | Beechey CV, et al. (1994) A new spontaneous W allele, W36H. Mouse Genome 92(3):502 |
| abstractText | Full text of Mouse Genome: Research News: 1. A new spontaneous W allele, W36H. A male mouse, heterozygous for the Chr 6 genes sightless (Sjg), lurcher (Lc) and (Miwh) white has been found with white spotting exceptionally covering over 75 per cent of the coat. It was discovered among the offspring of an untreated Sig Lc Miwh/+++ male mated with two (C3H/HeH x 101/H)F1, females. No other mice with white spotting were found among a total of 55 young produced by this mating. The exceptional male on being outcrossed to wild type females produced further offspring of equivalent phenotype but also wild type young, and animals with ventral spots and occasionally white feet and tails. A dominant spotting mutation, causing the low grade spotting and that interacts with Mi wh to give the extensive spotting, was therefore suspected. An allelism test with the dominant spotting gene Sl (steel) was therefore carried out using the low grade spotting animals, but no evidence for allelism was seen although the double heterozygote had many white patches, mainly dorsal. The putative spotting mutant was then crossed to heterozygous Rw (rump-white) and here clear evidence of an interaction was found; the compound showed extensive white spotting with pigmented areas confined to the anterior third of the body. In crosses to wild type these double heterozygotes produced a total of 157 young, 73 Rw; 48 with definite belly spots, and a further 36 showed a near wild type phenotype. The latter were probably low grade examples of the new mutation as the majority had white feet and tail tips. More significantly no animals with the compound phenotype were produced. This suggested that the new mutant was very closely linked to Rw and probably an allele of dominant spotting (W) or patch (Ph). Intercross openings of the new mutant were carried out, with autopsies during late pregnancy. From a total of 69 embryos, 16 were anaemic and therefore presumptive homozygotes; there were no other abnormalities. These findings indicated that the mutation involves the W rather than the Ph locus, as homozygotes for the latter usually have facial abnormalities and are not anaemic. In addition when heterozygotes for the new mutant were intercrossed and allowed to litter, a few anaemic young were born but they died within a few hours. Allelism with W was confirmed by crossing the new mutant to Wbd when viable black-eyed white offspring were produced. Thus the new mutation is a W allele and has been given the symbol W36H. (Beechey and M. Harrison). |
