| First Author | Cattanach BM | Year | 1987 |
| Journal | Mouse News Lett | Volume | 77 |
| Pages | 122 | Mgi Jnum | J:85396 |
| Mgi Id | MGI:2674374 | Citation | Cattanach BM, et al. (1987) A new curtailed mutation. Mouse News Lett 77:122 |
| abstractText | Research News. 1. New mutants. a) A new curtailed mutation. A brachyury mutation detected in a combined TEM-X-ray mutation experiment (Cattanach and Rasberry, MNL 75: 25-26, 1986) appears to be a repeat of curtailed, (Searle, Ganet. Res. 7: 86-95, 1966) and accordingly has been designated curtailed-2H, Tc-2H. The mutant heterozygote lacks a normal tail, typically possessing on1y a short boneless caudal filament but often being completely tailless. Only one animal with a boned though still rudimentary tail has been found. The phenotype may therefore be more extreme than that of the original mutation. Crosses with normal mice have yielded 286 Tc-2H and 282 + young, classified at birth, thus indicating full viability to this age. Pre-weaning mortality is higher than the normal sibs, however (14% vs. 3%). Intercrosses have produced 94 Tc-2H and 54 + young, which is significantly different from a 3: 1 ratio (X 2/1 = 10.12) and suggests that the homozygote, like the Tc homozygote, is a prenatal lethal. Dissections of pregnant females at 17 day's gestation have indeed revealed evidence of a lethal class; 48 resorbtion moles were found among 48 Tc-2H and 25 + foetuses. Evidence of T allelism was obtained from linkage tests with the chromosome 17 marker tf and from interactions with T and th2. The cross of a Tc-2H +/+ tf male with 2 +tf/+tf females yielded 14 Tc-2H and 20 tf progeny, classified at 4 weeks of age, the absence of recombinants indicating close linkage. The reciprocal cross of 4 Tc-+2H +/+ tf females with 2 +tf/+tf males, however, produced 5 Tc-2Htf and 2 + recombinants among 32 Tc-2H and 48 tf young, giving a R.F. of 5.8 +/- 2.92%. The data accord relatively well with SearleÕs Tc-tf linkage data and together with these suggest recombination in this region is higher in females than males. Searle however only observed the sex difference in coupling backcross. Crosses of Tc-2H with T heterozygotes yielded 24 Tc-2H young, 20 T and 28 +; the shortage of abnormal tailed young together with a reduction in litter size indicates that the compound is lethal. The stage of development at which the compound dies has not yet been ascertained. Crosses of Tc-2H+ with +th2/+th2 mice yielded 16 + and 15 Tc young, with 3 of the latter having semi-paralysed hind-limbs and another having spina bifida. Searle observed such severe effects in compounds of Tc and th3. (Cattanach and Rasberry) |
