草鱼和鲤杂交的细胞学研究——鱼类远缘杂交核质不同步现象

STUDIES ON CYTOLOGY OF CROSSES BETWEEN GRASS CARP AND CARP——ASYNCHRONIZATION BETWEEN NUCLEUS AND CYTOPLASM IN DISTANT HYBRIDIZATION OF FISHES

以草鱼(Ctenopharyngodon idellus)为母本、鲤(Cyprinus carpio)为父本进行人工杂交,杂种胚胎发育至孵化期全部死亡;同时获得了少数雌核发育草鱼和雄核发育的鲤。分析比较了草鲤杂种胚胎染色体变化及胚胎发育情况。发现杂种胚胎染色体数目变化较大,一般在24—73之间,绝大部分细胞染色体在发育过程中不断丢失而出现非整倍体;极少数细胞在受精后雌性原核和雄性原核不结合而引起雌核发育和雄核发育;草鱼和鲤胚胎发育时序有较大差别;因此细胞分裂不能同步。可能是杂种胚胎染色体不断丢失的主要原因。

In the artificial hybridization between female grass carp (Ctenopharyngodon idellus) and male common carp (Cyprinus carpio), no hybrid embryos survived to hatching except a few gynogenetic grass carp and androgenetic common carp. Comparisons of karyotype and embryonic development between the hybrid and its parents (grass carp and common carp) showed that the chromosome number of hybrid embryos varied considerably, usually ranging from 24 to 73. Most chromosomes of common carp were gradually lost and aneuploid appeared in almost all the hybrid embryonic cells. A few embryos developed by means of gynogenesis or androgenesis. The difference in the rate of embryonic development between grass carp and common carp was distinct, and the characters of hybrid embryonic development were much closer to those of grass carp. Asynchronus development between plasma and male nucleus may be the cause for the continuous loss of chromosomes in the hybrid cells.