GENE-CENTROMERE MAPPING OF 25 LOCI IN RAINBOW-TROUT
GENE-CENTROMERE MAPPING OF 25 LOCI IN RAINBOW-TROUT
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DOI：
10.1093/oxfordjournals.jhered.a110247
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发表时间：
1986-09-01
影响因子：
3.1
通讯作者：
LEARY, RF
中科院分区：
文献类型：
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作者：
ALLENDORF, FW;SEEB, JE;LEARY, RF
我们通过对三个虹鳟鱼（S. gairdneri）孵化品系的雌核发育后代的半四分体分析，绘制了与其着丝粒相关的 25 个酶位点。对五个不连锁基因座接近 100% 杂合雌核发育二倍体的观察表明，近乎完全干扰在虹鳟鱼染色体中很常见。三倍体中基因着丝粒重组率的估计与雌核发育二倍体中的估计相似。因此，这些位点几乎不存在纯合子不能用纯合子存活率降低来解释。此外，我们在 69 次比较中没有发现两个纯合类偏离平等的证据，如果等位基因与降低生存率的隐性等位基因相关，则可以预期。令人惊讶的是，我们还发现很少有证据表明品系内部或品系之间的家族之间存在差异。所有位点杂合后代的平均比例为0.56；这对应于仅一代后的固定指数为 0.44。然而，几乎所有雌核发育后代都是杂合的位点频率很高，这表明通过涉及虹鳟鱼第二极体保留的雌核发育产生纯合品系是不可行的。
We have mapped 25 enzyme loci in relation to their centromeres by half-tetrad analysis in gynogenetic progeny from three hatchery strains of rainbow trout (S. gairdneri). The observation of close to 100 percent heterozygous gynogenetic diploids for five unlinked loci suggests that near-complete interference is common in rainbow trout chromosomes. Estimates of gene-centromere recombination rates in triploids are similar to the estimates in gynogenetic diploids. Thus, the near absence of homozygotes at these loci cannot be explained by reduced survival of homozygotes. Furthermore, we found no evidence in 69 comparisons of departure from equality of the two homozygous classes, as would be expected if an allele was linked to a recessive allele that reduced survival. We also found surprisingly little evidence of differences among families within strains or among strains. The average proportion of heterozygous progeny for all loci is 0.56; this corresponds to a fixation index of 0.44 after only one generation. However, the high frequency of loci at which almost all gynogenetic progeny are heterozygous indicates that it is infeasible to produce homozygous lines by gynogenesis involving retention of the second polar body in rainbow trout.