【摘要】 本文报导双向选择对团头鲂生化遗传变异的影响。试验材料鱼包括来自淤泥湖的原种，１９８６－１９９４年群体选育的第四代（“选育 Ｆ４”），以及１９９１、１９９４年连续兄妹杂交的第二代（“近交Ｆ２”）。计检测了８种同工酶，１９个位点。三群体的多态座位比例一致（５．２６％），但平均杂合度趋异。“选育Ｆ４”平均杂合度最高（０．０２１３），“近交Ｆ２”最低（０．０１７４）。经４代选育，平均杂合度增加４％，而经２代近交，平均杂合度降低１５％。更多还原

【Abstract】 The effects of two - way selection on the variety of biochemical genetic markers of three groups of blunt snout bream (Megalobrama amblycephala ) were examined. One group of the brood stock fish were collecced from the Yuni Lake. The Second group are the 4th generation (1986-1994) produced by mass selection (selected-F4), and the third group are the 2nd generation (1991, 1994) of full-sib breeding (inbred -F4). Nineteen loci, 8 enzymes were studied. Results showed that, the ratio of the polymorphyism(P) were the same (5. 26% ) in 3 groups; but the average heterozygosity (H) showed divergent. The selcted -F4 was of the highest H - 0. 0213, the inbred-F2 was of the lowerest H-0.0174. The heterzygosity increased by 4% through 4 generations selection, in the other side, the heterozygosity decresaed to 15% through 2 generation of high inbreeding.更多还原