Fitzpatrick John L, Lüpold Stefan
Computational and Evolutionary Biology, Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, UK
Department of Biology, Life Sciences Complex, Syracuse University, 107 College Place, Syracuse, NY 13244-1270, USA.
Mol Hum Reprod. 2014 Dec;20(12):1180-9. doi: 10.1093/molehr/gau067. Epub 2014 Oct 16.
Sperm experience intense and varied selection that dramatically impacts the evolution of sperm quality. Selection acts to ensure that sperm are fertilization-competent and able to overcome the many challenges experienced on their way towards eggs. However, simply being able to fertilize an egg is not enough to ensure male fertility in most species. Owing to the prevalence of female multiple mating throughout the animal kingdom, successful fertilization requires sperm to outcompete rival sperm. In addition, females can actively influence sperm quality, storage or utilization to influence male fertility. This review provides an overview of how these selective forces influence the evolution of sperm quality. After exploring the link between sperm traits and male fertility, we examine how post-mating competition between rival ejaculates influences the evolution of sperm quality. We then describe how complex genetic, social and sexual interactions influence sperm quality, focusing on the importance of seminal fluid and interactions between sperm and the female's reproductive tract. In light of the complexities of selection on sperm traits, greater use of multivariate approaches that incorporate male-male, sperm-sperm and sperm-female interactions to study sperm quality will enhance our understanding of how selection acts on sperm traits and factors influencing male fertility. Because the metric of male reproductive success--fertilization--is the same across the animal kingdom, we argue that information about sperm evolution gained from non-human animals has enormous potential to further our understanding of the factors that impact human fertility.
精子经历着强烈且多样的选择，这对精子质量的进化产生了巨大影响。选择的作用是确保精子具备受精能力，并能够克服它们在向卵子游动过程中所面临的诸多挑战。然而，在大多数物种中，仅仅能够使卵子受精并不足以确保雄性的生育能力。由于在整个动物界雌性普遍存在多次交配的情况，成功受精需要精子战胜竞争对手的精子。此外，雌性可以积极影响精子质量、储存或利用，从而影响雄性的生育能力。本综述概述了这些选择力量如何影响精子质量的进化。在探讨了精子特征与雄性生育能力之间的联系后，我们研究了竞争射精之间的交配后竞争如何影响精子质量的进化。然后，我们描述了复杂的遗传、社会和性互动如何影响精子质量，重点关注精液的重要性以及精子与雌性生殖道之间的相互作用。鉴于精子特征选择的复杂性，更多地使用纳入雄性与雄性、精子与精子以及精子与雌性相互作用的多变量方法来研究精子质量，将增进我们对选择如何作用于精子特征以及影响雄性生育能力的因素的理解。因为雄性生殖成功的衡量标准——受精——在整个动物界都是相同的，我们认为从非人类动物获得的关于精子进化的信息对于进一步理解影响人类生育能力的因素具有巨大潜力。
