牙鲆群体Idh-1基因座位杂合型个体选择性优势

利用淀粉凝胶水平电泳法分析了人工牙鲆种苗群体的异柠檬酸脱氢酶同工酶 (IDH) .对牙鲆材料分析得知 Idh- 1基因座位只存在 A、B两个等位基因 ,而且在 2 3个样品群中 ,有 19个样品群呈现 A、B这两个等位基因所决定的基因型的杂合型个体过剩现象 ,表现出杂合基因型的选择性优势 .设定这 19个呈杂合型过剩样品群的死亡率为零 ,即以杂合型 A/ B的成活率为 10 0 %来计算其纯合型的成活率 ,得到纯合型个体 A/ A和 B/ B的成活率分别为 6 9.2 %和 75 .2 % ;从个体的标准体长上看 ,在表现为杂合型个体过剩的 19个样品群中 ,15个样品群的杂合型个体 (A/ B)大于纯合型个体 (B/ B) .其结果反映了牙鲆人工养殖放流群体的 Idh- 1的基因型与成活率及生长存在相关性 .

Selective Advantage of Heterozygotes at the Liver Isocitrate Dehydrogenase Locus in the Plaice

A cultured|released population of the plaice, Palaichthys olivaeus, was analyzed by starch gel electrophesis for liver isocitrate dehydrogenase isozyme (IDH). The universal occurrence of two alleles (A and B) at the Idh|1 locus was observed in 23 different lots from nine different hatcheries. An excess of heterozygotes at the Idh|1 locus was observed in 19 of 23 different lots, suggesting the selective advantage of heterozygotes. On the assumption that the heterozygotes rate 0% in mortality, the survival rates of homozygotes were calculated for the 19 lots showed heterozygote excess. The survival rate of A/A and B/B homozygotes was calculated at an average of 69.2 and 75.2%, respectively. The genotypes were associated with marked differences in survival rate. The standard body length of A/B heterozygotes was larger than that of B/B homozygotes in 15 of the 19 lots which showed heterozygotes excess. These results suggest a case of balance polymorphism. The maintenance of stable polymorphism could be explained by the differences of survival and growth rates among the genotypes.