草鱼同工酶基因座位多态性的初步研究

A PRELIMINARY STUDY ON THE POLYMORPHISMS OF ISOZYMIC LOCI IN GRASS CARP (CTENOPHARYNGODON IDELLUS)

采用垂直淀粉凝胶电泳及特异性组织化学染色技术研究了25尾草鱼的6种同工酶系统[ LDH ,MDH ,ADH, GDH, IDH, EST )约18—23个基因座位的遗传变异型。有7个基因座位(s-Mdh-A,Adh-B,Gdh-1,Gdh-2,Est-1,Est-6,Est-14)具有多态性,在其中4个基因座位(s-Mdh-A,Adh-B,Gdh-1,Est-1)上观察到的基因型频率与Hardy-Weinberg定律相符。实验表明草鱼的同工酶基因座位具有明显的多态性。这一结果为草鱼的人工选种和定向育种的可能性提供了依据。对草鱼GDH,EST同工酶的遗传基础、亚基组成以及酶变异的机理等问题进行了讨论。

The genetic variants of six isozymic systems (LDH, MDH, ADH, GDH, IDH, and EST) encoded approximately by 18 to 23 presumptive loci in 25 individuals of grass carp taken from the same locality were detected through vertical slab starch gel electrophoresis and subsequent specific histochemical staining techniques. Polymorphisms were observed at seven loci (s-Mdh-A, Adh-B, Gdh-1, Gdh-2, Est-1, Est-6, and Est-14), The observed frequencies of genotypes at four polymorphic loci (s-Mdh-A, Adh-B, Gdh-1, and Est-1) are all in accord with the Hardy-Weinberg's law of genetic equilibrium. Our results show that isozymic loci of grass carp possess obvious polymorphisms and indicate that there are possibilities of artificial selective breedings and directional breedings for grass carp.The genetic and molecular bases of GDH and EST isozymes of grass carp and the mechanisms in relation to the variation of enzymes are discussed.