Sex determination of bisected embryos and production of identical twins.

1.用细小的玻璃微针对小鼠胚胎8-细胞期胚胎、解压桑椹胚和早期囊胚进行了切割和染色体性别鉴定。囊胚期发育率分别为51.4%、78.4%和27.8%。将解压后的桑寄生切片后，对制备染色体分析准备的条件进行了讨论。结果表明，试管苗最适培养时间为15-18小时，秋水仙胺处理时间为3小时。对65枚桑囊胚和囊胚期胚胎进行了切割，并对其中一半的胚胎进行了染色体分析。38.5%的分割胚胎进行了性别鉴定。来自性别分割胚胎的小牛生长正常，产奶量正常。生产牛双胞胎两个未分割的胚胎被移植到一个子宫角中，或者每个子宫角上都有一个胚胎。妊娠率分别为62.4%和69.4%，差异无统计学意义。单角移植的流产率为20.6%。牛同卵双胞胎的生产将分割后的胚胎通过双胞胎或单胎移植。妊娠率分别为72.6%和61.5%。双胎和单胎移植的受孕率分别为71.0%和23.1%。双胎和单胎的同卵双生率分别为45.2%和15.4%。单次移植可观察到大量死产和流产病例。

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.