| First Author | Rasberry C | Year | 1994 |
| Journal | Mouse Genome | Volume | 92 |
| Issue | 3 | Pages | 504-5 |
| Mgi Jnum | J:27502 | Mgi Id | MGI:74991 |
| Citation | Rasberry C, et al. (1994) A new mutation at the Ph locus. Mouse Genome 92(3):504-5 |
| abstractText | Full text of Mouse Genome contribution: Research News: 6. A new mutation at the Ph locus. A new mutation has been detected in a specific locus experiment, in which 101/H males had been spermatogonially irradiated with 6 Gy X-rays. The original mutant, a female showed a high level of white spotting, resembling piebald (s). On crossing with a homozygous s male, the female produced + as well as white spotted animals, but the latter fell into two classes, showing high and low levels of spotting. On the basis of the + progeny the mutation did not involve the s locus. On crossing the female with a + male 59 white spotted animals and 53 + animals were produced suggesting that the mutation is inherited as a dominant. However, the white spotted animals showed a variation in expression, 23 showed spotting mainly on the belly, whilst 36 had a broad belt of white all around the body between the front and hind legs. A likely explanation for this is an interaction with s which was segregating in the cross. The pattern of expression of the new dominant spotting gene, suggests that the mutation is either patch (Ph) on Chr 5, or splotch (Sp) on Chr 1. Crosses with rump-white (Rw), which lies very close to Ph on Chr 5, produced almost totally white animals, with pigmentation confined to the head. On crossing these with +, 50 spotted, 48 Rw, 1 + and 5 which showed what appeared to be a high Rw expression were produced. The data thus clearly shows that the new mutation lies in the vicinity of Rw on Chr 5. However, whereas the classification of the + animal was unambiguous, there was uncertainty over the classification of the 5 extensively white marked putative recombinants. As s was still segregating in the crosses a Rw-s interaction might be predicted, implying that these animals were only extreme Rw and not recombinants. It therefore seemed likely that the mutation involved the Ph locus. In order to determine if the mutation was Ph, intercrosses between heterozygotes were set up and the females opened at 13.5 - 15.5 days gestation. Pre-implantation loss was 13.14% (n=16) compared with a control of 8.75% (n=8). The post-implantation loss, in the form of small moles, was 25.00% compared with the control value of 1.37% indicating that homozygotes die before birth. However more significantly, about 6% of the live embryos showed facial abnormalities including bloodspots, blebs, or a cleft or split face, which are features of Ph homozygotes (Lyon and Searle, GVSLM 2nd Edition, Chapter 2,1989). We can conclude that the new mutation involves the Ph locus; it has been denoted Ph3H (Rasbeny and Cattanach). (Supported by Euratom Contract Bi:6-143). |
