| First Author | Cattanach BM | Year | 1996 |
| Journal | Mouse Genome | Volume | 94 |
| Pages | 678 | Mgi Jnum | J:69257 |
| Mgi Id | MGI:1934361 | Citation | Cattanach BM, et al. (1996) Two Sey (Pax6) mutants. Mouse Genome 94:678 |
| abstractText | Full text of Mouse Genome contribution: Research News: 1. New Mutants. (a) Two Sey (Pax6) mutants. Two new Sey mutations, named Sey(2H) and Sey(3H) have been detected in combined chemical-radiation mutagenesis experiments (Cattanach et a1 Nature Genetics 3: 56-61, 1993; Cattanach et a1 Proc of the 10th ICRR, Vol. 2, in press). Both resemble the Sey(1H) allele in that they are more severely affected than the original Sey mutation, being smaller at birth and showing low grade white spotting. With both, there was a shortage of affected animals at birth (56% and 60%, respectively) and, with both, survival to weaning was seen to be reduced (54% and 68%, respectively). Openings at 15 days' gestation of normal females mated with Sey(2H) males indicated an elevated frequency of exencephaly among the foetuses. However, it was not clear if these all belonged to the Sey(2H) class, which might help account for the shortage of the mutants at birth. Somewhat elevated post- implantation losses were also found (11%), suggesting a further or alternative explanation for the shortage of heterozygotes at birth. It may be that heterozygotes die at a range of ages from early post-implantation stages, to birth as exencephalics, and also postnatally for reasons associated with their small size. Both exencephalics and higher levels of post-implantation loss (27%) were also found in intercrosses but, more notably, a very high incidence of pre-implantation loss was seen (38%, cf 2% in the outcrosses). It therefore seems most Sey(2H) homozygotes die before implantation. Equivalent crosses with the Sey(3H) mutation are still in progress. Evidence that the mutations involve the Sey locus has been provided by linkage with pa. Thus, crosses of Sey(2H) +/+ pa females and males with pa homozygotes generated the following phenotypic classes of offspring: 30 Sey(2H), 35 pa, 3 Sey(2H) pa and 3 +, total 71 giving a RF, 8.45 +/- 3.3%. Equivalent crosses using Sey(3H) generated the following phenotypic classes: 68 Sey(3H), 72 pa, 0 Sey(3H) pa and 6 +, total 146 to give a RF of 4.11 +/- 1.6 4%. Both estimates are in good accord with the Sey -pa map distance of 6 cM (Lyon et al, Mouse Genome 94: 19-73, 1996). The viabilities of the Sey mutants was clearly near-normal in these linkage tests. No cytogenetic abnormality could be detected in mice carrying either mutation. (Cattanach, Rasberry, Evans and Woodward). |
