Sex determination of bisected embryos and production of identical twins.

点击翻译按钮获取中文摘要

1. Bisection and sex determination by chromosome analysis on mouse embryos Eight-cell stage embryos, decompacted morulae and early blastocysts were bisected by using a fine, glass microneedle. The rates of development up to the blastocyst stage were 51.4, 78.4 and 27.8 %, respectively. After decompacted morulae were bisected, the condition of making chromosome analysis preparation were discussed. It was found that the optimum duration of in vitro culture was 15-18 hours and treatment with colcemid was 3 hours.2. Bisection and sex determination by chromosome analysis on bovine embryos Sixty-five morulae and blastocyst stage embryos were bisected and chromosome analysis was conducted on half of the demi-embryos. Sex was determined in 38.5 % of the bisected embryos. Calves from sexed-bisected embryos grew normally and milk production was normal.3. Production of bovine twins Two non-bisected embryos were either transferred into a single uterine horn or one embryo on each horn. There was no significant difference on the pregnancy rates which were 62.4 and 69.4 %, respectively. The abortion rate for single horn transfer was 20.6 %.4. Production of bovine identical twins The bisected embryos were transferred either by twin or single transfer. The pregnancy rates were 72.6 and 61.5 %, respectively. In twin and single transfers, 71.0 and 23.1 % resulted in pregnancy, respectively. Identical twins were produced in 45.2 and 15.4 % in twin and single transfers, respectively. Many stillbirth and abortion cases were observed when single transfer was conducted.