银鲫生殖方式多样性的转铁蛋白的同工酶标记的遗传分析

用银鲫克隆D，克隆A和鲤鱼的精子分别与银鲫克隆F的卵子受精产生了三种繁殖组合FD，FA和FL；再用转铁蛋白和同工酶标记对这三种组合的遗传模式进行比较研究。结果发现，FL组合的子代具有其母本完全相同的体形和电泳图谱，表现出雌核生殖银鲫的克隆品性。而在FD组合中则出现了体形的分化和酶谱的多态性；在一些个体的蛋白座位上同时检测到了父本和母本各自特有的谱带，证明FD生殖过程中有性重组的发生。同时，在所研究的蛋白的不同座位上存在着极端的连锁不平衡现象，可以推断在FD的重组过程中多个基因座位组成的连锁群（甚至是染色体组）可能作为一个整体参与基因的传递。此外，不同的蛋白座位上都未观察到重组的纯合表型，暗示在不同的基因连锁群之间还可能存在一种平衡致死的机制。FA组合的F1代具有类似母本克隆F的体形和蛋白表型，FA组合俱本近交产生的F2代却同时出现了克隆F和克隆A的体形和表型。即父本和母本的染色体组都能够通过有性生殖传递给FA子代，然而可能由于父母本基因的不相容性而使F1代父本的基因表达受到抑制。相对于雌核生殖的克隆遗传 ，本研究的揭示出来的有性生殖特性及伴随的有性质组能够使银鲫在一定程度上卸去积累的遗传负荷并从其它种群获取新的基因型，以维持其遗传多样性。多种可选择的生殖方式可能对于银鲫在自然条件下的生态适应有着重要意义，对于银鲫的遗传选育和养殖管理也有一定的参考价值。

Genetic analysis on diversity of reproductive modes of silver crucian carp inferred by transferrin and isozyme markers]

Silver crucian carp (Carassius auratus gibelio) has been known for its gynogenetic reproduction. In this paper, eggs from clone F of gynogenetic silver crucian carp were inseminated respectively by sperms of clone D, clone A and common carp, and polymorphic patterns of transferrin and isozymes of the produced three offspring FD, FA and FL were studied comparatively to explore the diversity in reproductive modes of silver crucian carp. As control, zymograms of FL progenies exhibited a maternally clonal inheritance, and gynogenesis was reconfirmed. However, differentiation of morphs and electrophoretic patterns was both observed among the FD progenies, and detection of bands specific for the clone F or clone D in some FD individuals urged the occurrence of recombination. Furthermore, extreme linkage disequilibrium for different protein loci suggested that linkage groups composed of different genes might function as the fundamental unit in the recombination. With respect to FA group, phenotypes of parental clones were both detected in the F2 generation (FA x FA progenies) while only maternal phenotypes were detected in the F1 generation. It appeared that both the parental chromosome sets could be transmitted to the offspring but expression of paternal genes were fundamentally upset in the F1 generation because of incompatibility of the parental genes. Generally, genetic analysis of FD and FA offspring primarily exhibited a particular syngamy for silver crucian carp. Besides the clonal reproduction of gynogenesis, syngamy could provide opportunities of recombination for silver crucian carp, which might remove some genetic loads from the genome and introduce new genotypes. Diversity in reproductive modes might play an important role in ecological adaptation of silver crucian carp.