| First Author | Falconer DS | Year | 1956 |
| Journal | Mouse News Lett | Volume | 15 |
| Pages | 24-25 | Mgi Jnum | J:164 |
| Mgi Id | MGI:48704 | Citation | Falconer DS (1956) Viable and fertile Brindled male, and new evidence for the allelism of the sex-linked genes, Brindled and Mottled. Mouse News Lett 15:24-25 |
| abstractText | Full text of MNL contribution: Viable and fertile Brindled male, and new evidence for the allelism of the sex-1inked.genes, Brindled and Mottled. All Brindled males so far examined, which must run to several hundreds, have died before or soon after weaning. It was therefore an event of great interest when one survived the usual time of death, reached adulthood, and was proved fertile. This male is now 8 months old and has sired many litters. The coat is white except for the tips of the hairs which have some pigment. The eyes, ears, tail and scrotum are pigmented. There is a ÔneurologicalÕ involvement: slight tremor, uncoordinated gait, and characteristic reflex of the hind legs when the animal is held up by the tail, the feet clasping each other instead of being spread out. This male has enabled us to do two things hitherto impossible: (1) to produce homozygous Brindled females. These are in every way indistinguishable from Brindled males. As with Tabby, therefore, homozygotes and hemizygotes have the same phenotype. (2) to produce females heterozygous for both Mottled and Brindled, and so to test further the allelism of these genes, presumed hitherto from the fact that both are at the same distance from Tabby and on the same side. Three Mo/Br females were obtained: they were indistinguishable from Br/Br females or Br males, and died at the same age. This proves the allelism of Mo and Br, as far as it can be proved outside the pseudo field. I suppose we ought now to use the symbol Mobr for Brindled. The next question of interest is the reason for the survival of the exceptional Brindled male. In the progeny we have had 2 out of 10 Br males and 3 out of 10 Br/Br females that have survived to the age of 6 weeks or longer. The increased viability must therefore have a genetic basis, but it is too soon yet to say whether this is a 'background' effect or whether we have here a different allele of Br. (D.S. Falconer) |
