| First Author | von Lehmann E | Year | 1973 |
| Journal | Mouse News Lett | Volume | 48 |
| Pages | 23 | Mgi Jnum | J:22593 |
| Mgi Id | MGI:70446 | Citation | von Lehmann E (1973) Coat colour genetics of the tobacco-mouse (Mus poschiavinus Fatio). Mouse News Lett 48:23 |
| abstractText | Full text of MNL contribution: Research News: Coat colour genetics of the tobacco-mouse (Mus poschiavinus Fatio). 1. Distribution morphology and biometrical characteristics of the tobacco-mouse are described by A. Gropp, U. Tettenborn and E. von Lehmann (Experientia 25, 875-876, 1969; Cytogenetics 9, 9-23, 1970). 2. The colouring results from action of a darkening or umbrous factor (giving a non-agouti back) on wild-type grey (A). Young tobacco-mice cannot be distinguished from black mice until the 8th week; later the flanks become agouti. The coat colour does not vary in pure line breeding. 3. When tobacco-mice are crossed to black (aa) house mice, the F1 are wild type, except that the back may be darkened. Crosses to yellow (Ay) or agouti (A) give yellow or agouti mice with darkened back, though less so with agouti. 4. For cytogenetic reasons (see papers cited above) it is very difficult to obtain F2 and F3 mice from Mus poschiavinus - Mus musculus crosses. Fl matings are usually sterile. Only 60 F2 mice have been obtained in six years. As expected, there was segregation for coat colour into the F1 and parental phenotypes, but the original tobacco-mouse colour reappeared very rarely. Following the F3 and F4 generations, cross-bred mice become increasingly fertile. 5. In the F6 generation we started selecting for solid black colour. Surprisingly, this black breed yielded in F10 two mice with typical tobacco-mouse colouring (also having 14 metacentric chromosomes in their karyotypes, like tobacco-mice). 6. This suggests that, when homozygous, the darkening factor of Mus poschiavinus is epistatic over non-agouti. I agree with the opinion of A.G. Searle that it may belong to the extension (E) group (J. Hered. 59, 341, 1968). It is probably not identical with umbrous (U) because this shows more effect with Aa than AA mice but allelism tests have not yet been carried out. I give the tobacco-mouse darkening factor the provisional symbol of Tob. 7. The original tobacco-mice thus have the genotype TobTob AA, while the recovery of agouti mice with a darkened back after outcrossing to non-agouti (tobtob aa) shows that Tob is an incomplete dominant. Back-crossings of F1 mice to tobacco-mice (TobTob AA x Tobtob Aa) should give 50% dark and 50% grey with some darkening of the back. This was demonstrated during the proceedings of the Deutsche Gesellschaft fur Saugetierkunde on Oct. 3rd 1972. In no case was the classification in doubt. 8. A. Radbruch has found that the darkening gene is not located on one of the metacentric chromosomes (Zschr. Saugetierkunde, in press). * Editor's Note: See also Lubeck, for A. Gropp and colleagues (formerly Pathological Institute, Bonn). |
