Stabilizing selection on sperm number revealed by artificial selection and experimental evolution
Stabilizing selection on sperm number revealed by artificial selection and experimental evolution
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DOI：
10.1111/evo.13425
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发表时间：
2018-03-01
期刊：
影响因子：
3.3
通讯作者：
Pilastro, Andrea
中科院分区：
文献类型：
--
作者：
Cattelan, Silvia;Di Nisio, Andrea;Pilastro, Andrea
精子竞争在动物分类学上广泛存在，通常与大量精子产生有关，竞争池中精子的数量是受精成功的主要预测因素。尽管强烈的交配后选择直接作用于精子产生，但其遗传变异往往很高。这可以解释为精子生产和与配偶获得或生存相关的性状之间的权衡，这可能有助于产生整体稳定的选择。为了研究这一假设，我们首先人工选择雄性孔雀鱼（Poecilia reticulata）的高和低精子产量三代，同时消除性选择。然后，我们中断了人工选择，恢复了性选择。精子产量在一代中对趋异选择作出反应，当我们恢复性选择时，高、低品系在两代内都收敛到原始群体的平均精子产量，表明精子数量受到强稳定的总性选择的影响（即，选择同时作用于与繁殖成功相关的所有性状）。我们讨论了可能的机制，负责维持高遗传变异的精子生产，尽管强大的选择作用于它。
Sperm competition is taxonomically widespread in animals and is usually associated with large sperm production, being the number of sperm in the competing pool the prime predictor of fertilization success. Despite the strong postcopulatory selection acting directionally on sperm production, its genetic variance is often very high. This can be explained by trade-offs between sperm production and traits associated with mate acquisition or survival, that may contribute to generate an overall stabilizing selection. To investigate this hypothesis, we first artificially selected male guppies (Poecilia reticulata) for high and low sperm production for three generations, while simultaneously removing sexual selection. Then, we interrupted artificial selection and restored sexual selection. Sperm production responded to divergent selection in one generation, and when we restored sexual selection, both high and low lines converged back to the mean sperm production of the original population within two generations, indicating that sperm number is subject to strong stabilizing total sexual selection (i.e., selection acting simultaneously on all traits associated with reproductive success). We discuss the possible mechanisms responsible for the maintenance of high genetic variability in sperm production despite strong selection acting on it.