Outcrossing and the maintenance of males within C. elegans populations.
Outcrossing and the maintenance of males within C. elegans populations.
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DOI：
10.1093/jhered/esq003
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发表时间：
2010-03-01
期刊：
影响因子：
--
通讯作者：
Phillips, Patrick C
中科院分区：
文献类型：
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作者：
Anderson, Jennifer L;Morran, Levi T;Phillips, Patrick C
秀丽隐杆线虫是一种雌雄异株线虫，雌雄同体。虽然雄性在避免近亲繁殖和促进适应方面可能发挥重要作用，但它们的存在在进化上是有问题的，因为它们不像雌雄同体那样直接产生后代。这篇综述探讨了遗传学、群体基因组学和实验进化方法如何被用来解决雄性和异交在C.优雅的虽然理论上认为近亲繁殖抑制和雄性交配能力应该是雄性频率的主要决定因素，但这还没有得到令人信服的实验证实。自然种群的基因组分析发现，异交发生在低，但不可忽略的水平，并观察到的模式与强大的自交连锁不平衡，而不是产生自然选择对异交后代。最近的实验性进化研究表明，如果种群开始时具有足够的遗传变异和/或通过环境的变化受到强烈的自然选择，雄性可以保持在相当高的水平。例如，如本文所述，适应新的实验室饲养和温度制度的种群保持雄性的频率在5%至40%之间。实验室和现场的结果仍然等待充分的和解，这可能有助于通过确定潜在的基因座交配系统动态的菌株差异。
Caenorhabditis elegans is an androdioecious nematode with both hermaphrodites and males. Although males can potentially play an important role in avoiding inbreeding and facilitating adaptation, their existence is evolutionarily problematic because they do not directly generate offspring in the way that hermaphrodites do. This review explores how genetic, population genomic, and experimental evolution approaches are being used to address the role of males and outcrossing within C. elegans. Although theory suggests that inbreeding depression and male mating ability should be the primary determinants of male frequency, this has yet to be convincingly confirmed experimentally. Genomic analysis of natural populations finds that outcrossing occurs at low, but not negligible levels, and that observed patterns of linkage disequilibrium consistent with strong selfing may instead be generated by natural selection against outcrossed progeny. Recent experimental evolution studies suggest that males can be maintained at fairly high levels if populations are initiated with sufficient genetic variation and/or subjected to strong natural selection via a change in the environment. For example, as reported here, populations adapting to novel laboratory rearing and temperature regimes maintain males at frequencies from 5% to 40%. Laboratory and field results still await full reconciliation, which may be facilitated by identifying the loci underlying among-strain differences in mating system dynamics.