| First Author | Rasberry C | Year | 1995 |
| Journal | Mouse Genome | Volume | 93 |
| Pages | 1028 | Mgi Jnum | J:106415 |
| Mgi Id | MGI:3618466 | Citation | Rasberry C (1995) Time of death of Td males. Mouse Genome 93:1028 |
| abstractText | Full text of Mouse Genome contribution: 2. Time of death of Td males. Tattered (Td) is a semi-dominant mutation located close to spf on the proximal part of the X-chromosome (Cattanach, MNL 67:19). Td+ females are viable but exhibit considerable variation in expression. Moderately affected adults show a slight striping of the coat similar to some of the Ta alleles More severely affected animals are often small in size with scarring of the skin resulting in noticeable bald patches on the coat and tail Some individuals also have abnormally shaped heads, bent tails and twisted toes, possibly indicating mild skeletal abnormalities. About 15% of these extreme heterozygotes die pre-weaning and it was suspected that there was also some pre-natal loss (Cattanach, MNL 66:61). Not surprisingly, Td is a pre-natal lethal in the male but the time and cause of death has not been established. In order to estimate the time of death of Td males, Td+ females were mated to wild-type (++) males and opened at 12.5-13.5d gestation. The results are shown in Table 1 together with those of wild- type controls. Type of Cross: Td + ffx++mm; No. ff: 8; No. Implants: 71; Normal live embryos: 45; Dead embryos or retarded: 17; Embryonic remains/large moles: 3; Small moles: 6; Corpora lutea: 74. Type of Cross: ++ffx++mm; No. ff: 4; No. Implants: 38; Normal live embryos: 37; Dead embryos or retarded: 0; Embryonic remains/large moles: 0; Small moles: 1; Corpora lutea: 38. The low incidence of pre-implantation loss (74-71/74) clearly suggests that the loss of Td males occurs after implantation. The incidences of small moles and large moles/ embryonic remains are relatively low (approximately 8% and 4% respectively). However there were significant numbers of dead embryos and severely retarded live embryos (24%) which suggests that these comprise the Td male class. To investigate this further, chromosome preparations were made from the embryonic membranes of a sample of 36 normal live embryos, 7 dead embryos and 4 severely retarded embryos using the method of Evans. (In Mammalian Development, IRL Press 93-114, 1975). These were then C-banded to determine the presence/absence of a Y chromosome. Of the 36 normal live embryos, 24 were chromosomally XX and 12 were XY. Of the 7 dead embryos, 2 were XX and 5 XY, and of the 4 live retarded embryos 2 were XX and 2 were XY. The presence of XX dead embryos suggests that there is a small pre-natal loss of Td+ females before 12.5d and continuing beyond 13.5d gestation, when XX live retarded embryos are still found. This overlaps with the loss of Td males which are found both as dead and as live retarded embryos at 12.5-13.5d gestation. Whether further Td male losses occur before 12.5d or after 13.5d is uncertain (Rasberry, Beechey and Cattanach). |
