Kaufman M H, Sachs L
J Embryol Exp Morphol. 1976 Feb;35(1):179-90.
The present experiments were undertaken to determine whether, in parthenogenesis, heterozygous embryos develop better than homozygous embryos. Such experiments may provide an approach to elucidating whether fertilized embryos develop better than parthenogenetic ones because of heterozygosity, or if the sperm provides another contribution necessary for complete embryonic development. The parthenogenetic embryos studied included uniform haploids after extrusion of the second polar body, mosaic haploids in which each blastomere contained a genetically different haploid nucleus, and heterozygous diploid mouse embryos. Eggs were activated and cultured in a chemically defined medium. About three times as many mosaic haploid or heterozygous diploid eggs developed beyond the 4-cell stage after 98-100 h and to the blastocyst stage after 120 h in culture, than uniform haploid eggs. This indicates that the development of parthenogenetic embryos is probably under genetic control and that there was a better development of the heterozygous embryos. Mosaic haploid embryos showed the same high frequency of development as heterozygous diploids. The results therefore indicate that heterozygosity provided a developmental advantage even when distributed between two genetically different clones of cells in the same embryo.
开展本实验的目的是确定在孤雌生殖过程中，杂合胚胎是否比纯合胚胎发育得更好。此类实验或许能为阐明以下问题提供一种方法：受精胚胎是否因杂合性而比孤雌生殖胚胎发育得更好，或者精子是否为胚胎的完全发育提供了其他必要的贡献。所研究的孤雌生殖胚胎包括排出第二极体后的均匀单倍体、每个卵裂球都含有基因不同的单倍体细胞核的嵌合单倍体，以及杂合二倍体小鼠胚胎。卵子在化学成分明确的培养基中被激活并培养。培养98 - 100小时后，发育到4细胞期以上且培养120小时后发育到囊胚期的嵌合单倍体或杂合二倍体卵子数量约为均匀单倍体卵子的三倍。这表明孤雌生殖胚胎的发育可能受基因控制，且杂合胚胎发育得更好。嵌合单倍体胚胎与杂合二倍体胚胎表现出相同的高发育频率。因此，结果表明即使杂合性分布在同一胚胎中两个基因不同的细胞克隆之间，它也提供了发育优势。
