Department of Evolutionary Biology, Uppsala University, Norbyvägen 18D, Uppsala, SE-752 36, Sweden.
Division of Evolutionary Biology, Faculty of Biology, Ludwig-Maximilians-Universität München, Grosshaderner Strasse 2, Planegg-Martinsried, 82152, Germany.
Nat Commun. 2018 Apr 24;9(1):1639. doi: 10.1038/s41467-018-04054-6.
Sexual reproduction in eukaryotes requires the fusion of two compatible gametes of opposite sexes or mating types. To meet the challenge of finding a mating partner with compatible gametes, evolutionary mechanisms such as hermaphroditism and self-fertilization have repeatedly evolved. Here, by combining the insights from comparative genomics, computer simulations and experimental evolution in fission yeast, we shed light on the conditions promoting separate mating types or self-compatibility by mating-type switching. Analogous to multiple independent transitions between switchers and non-switchers in natural populations mediated by structural genomic changes, novel switching genotypes readily evolved under selection in the experimental populations. Detailed fitness measurements accompanied by computer simulations show the benefits and costs of switching during sexual and asexual reproduction, governing the occurrence of both strategies in nature. Our findings illuminate the trade-off between the benefits of reproductive assurance and its fitness costs under benign conditions facilitating the evolution of self-compatibility.
真核生物的有性生殖需要两个相容的雌雄配子或交配型的融合。为了应对寻找具有相容配子的交配伙伴的挑战，雌雄同体和自受精等进化机制已经反复进化。在这里，我们通过将裂殖酵母的比较基因组学、计算机模拟和实验进化的见解结合起来，揭示了通过交配型转换促进分离的交配型或自亲和性的条件。类似于自然种群中由结构基因组变化介导的开关和非开关之间的多次独立转换，新的转换基因型在实验种群中很容易通过选择进化。详细的适应度测量和计算机模拟表明，在有性和无性繁殖过程中，开关的收益和成本，决定了这两种策略在自然界中的发生。我们的研究结果阐明了在促进自亲和性进化的良性条件下，生殖保证的收益与适应度成本之间的权衡。
