Department of Ecology & Evolutionary Biology, University of Toronto, Toronto, ON, M5S 3B2, Canada.
New Phytol. 2019 Nov;224(3):1080-1094. doi: 10.1111/nph.16075. Epub 2019 Aug 18.
The evolution of predominant self-fertilisation frequently coincides with the evolution of a collection of phenotypes that comprise the 'selfing syndrome', in both plants and animals. Genomic features also display a selfing syndrome. Selfing syndrome traits often involve changes to male and female reproductive characters that were subject to sexual selection and sexual conflict in the obligatorily outcrossing ancestor, including the gametic phase for both plants and animals. Rapid evolution of reproductive traits, due to both relaxed selection and directional selection under the new status of predominant selfing, lays the genetic groundwork for reproductive isolation. Consequently, shifts in sexual selection pressures coupled to transitions to selfing provide a powerful paradigm for investigating the speciation process. Plant and animal studies, however, emphasise distinct selective forces influencing reproductive-mode transitions: genetic transmission advantage to selfing or reproductive assurance outweighing the costs of inbreeding depression vs the costs of males and meiosis. Here, I synthesise links between sexual selection, evolution of selfing and speciation, with particular focus on identifying commonalities and differences between plant and animal systems and pointing to areas warranting further synergy.
自交的进化常常与一系列表型的进化同时发生，这些表型构成了“自交综合征”，无论是在植物还是动物中都是如此。基因组特征也表现出自交综合征。自交综合征的特征通常涉及到雄性和雌性生殖特征的改变，这些特征在强制性异交的祖先中受到性选择和性冲突的影响，包括植物和动物的配子阶段。由于在主要自交的新状态下选择放松和定向选择，生殖特征的快速进化为生殖隔离奠定了遗传基础。因此，性选择压力的转变与向自交的转变相结合，为研究物种形成过程提供了一个强大的范例。然而，植物和动物的研究强调了影响生殖模式转变的不同选择压力：自交的遗传传递优势或生殖保障超过了近交衰退的成本与雄性和减数分裂的成本之比。在这里，我综合了性选择、自交进化和物种形成之间的联系，特别关注植物和动物系统之间的异同，并指出需要进一步协同的领域。
