Weider L J
Max-Planck-Institute for Limnology, Department of Ecophysiology, Plön, Federal Republic of Germany.
Heredity (Edinb). 1989 Feb;62 ( Pt 1):1-10. doi: 10.1038/hdy.1989.1.
Population genetic studies of cyclically parthenogenetic organisms have focussed on members of the freshwater cladoceran crustaceans, and mainly on those populations which inhabit intermittent or permanent ponds. Little is known of the genetic structure of large-lake populations. The genetic structure of populations of the predatory freshwater littoral-zone cladoceran, Polyphemus pediculus from 20 palearctic lakes in Northern Germany was examined by electrophoresis to determine its breeding system and level of genetic polymorphism, and to compare its genetic structure with those of other Cladocera. Polyphemus was polymorphic for three of eight enzyme loci and most (20/23) genotypic frequencies were in Hardy-Weinberg equilibrium. These populations are thus panmictic, and most likely reproduce by cyclical parthenogenesis. There were heterozygote deficiencies at each of the polymorphic loci in the three deviant populations. Genetic differentiation between populations was evident at each locus, with significant spatial autocorrelation found at the Pgm locus. Population heterozygosity averaged 9.2 per cent with a mean of 1.5 alleles/locus. Mean number of composite genotypes per population was 6.0+/-1.0 (S.E.) with a range of 1-17 clones per population. P. pediculus thus has a population genetic structure similar to that of large-lake Daphnia populations.
对周期性孤雌生殖生物的群体遗传学研究主要集中在淡水枝角类甲壳动物成员上，且主要针对栖息于间歇性或永久性池塘的种群。对于大型湖泊种群的遗传结构了解甚少。通过电泳分析了来自德国北部20个古北区湖泊的捕食性淡水沿岸带枝角类动物——蚤状大眼溞种群的遗传结构，以确定其繁殖系统和遗传多态性水平，并将其遗传结构与其他枝角类动物的进行比较。在八个酶位点中的三个位点上，蚤状大眼溞表现出多态性，并且大多数（20/23）基因型频率处于哈迪-温伯格平衡。因此，这些种群是随机交配的，最有可能通过周期性孤雌生殖进行繁殖。在三个偏离的种群中，每个多态位点都存在杂合子不足。在每个位点上，种群之间的遗传分化都很明显，在磷酸葡萄糖变位酶（Pgm）位点发现了显著的空间自相关性。种群杂合度平均为9.2%，每个位点平均有1.5个等位基因。每个种群的复合基因型平均数为6.0±1.0（标准误），每个种群的克隆数范围为1 - 17个。因此，蚤状大眼溞的种群遗传结构与大型湖泊中溞属种群的相似。
