Hebert P D
Genetics. 1974 Jun;77(2):323-34. doi: 10.1093/genetics/77.2.323.
In permanent habitats populations of the cyclical parthenogen, Daphnia magna, reproduce by continued parthenogenesis and are subject to only sporadic sexual recruitment. The genetic effects of this breeding system have been investigated by analyzing allozyme frequencies in thirteen populations of D. magna.-Genotypic frequencies at polymorphic loci characteristically deviated markedly from Hardy-Weinberg proportions and gametic phase imbalance between loci was frequent. Genotypic frequencies were subject to violent, selectively determined oscillations over short periods of time. These observations suggest that permanent populations of D. magna ordinarily consist of a limited number of highly structured genotypes. The adaptational advantages offered by such structuring may have been a major selective factor favoring the evolution of cyclical parthenogenesis.
在周期性孤雌生殖的大型溞的永久栖息地种群中，通过持续的孤雌生殖进行繁殖，并且仅偶尔有有性生殖补充。通过分析13个大型溞种群的等位酶频率，对这种繁殖系统的遗传效应进行了研究。多态位点的基因型频率显著偏离哈迪-温伯格比例，并且位点间的配子相不平衡很常见。基因型频率在短时间内会受到剧烈的、由选择决定的波动影响。这些观察结果表明，大型溞的永久种群通常由数量有限的高度结构化基因型组成。这种结构所提供的适应性优势可能是有利于周期性孤雌生殖进化的一个主要选择因素。
