Ecological Genetics Research Unit, Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, P.O. Box 65, FI-00014, Helsinki, Finland.
Institute for Research Initiatives, Nara Institute of Science and Technology, Ikoma, Nara, 630-0192, Japan.
Nat Commun. 2019 Jan 11;10(1):145. doi: 10.1038/s41467-018-08014-y.
Sex determination is a fundamentally important and highly diversified biological process, yet the mechanisms behind the origin of this diversity are mostly unknown. Here we suggest that the evolution of sex determination systems can be driven by a chromosomal inversion. We show that an XY system evolved recently in particular nine-spined stickleback (Pungitius pungitius) populations, which arose from ancient hybridization between two divergent lineages. Our phylogenetic and genetic mapping analyses indicate that the XY system is formed in a large inversion that is associated with hybrid sterility between the divergent lineages. We suggest that a new male-determining gene evolved in the inversion in response to selection against impaired male fertility in a hybridized population. Given that inversions are often associated with hybrid incompatibility in animals and plants, they might frequently contribute to the diversification of sex determination systems.
性别决定是一个非常重要且高度多样化的生物学过程，但这种多样性产生的机制在很大程度上还不清楚。在这里，我们提出性别决定系统的进化可能是由染色体倒位驱动的。我们表明，一种 XY 系统最近在特定的九刺鱼（Pungitius pungitius）种群中进化而来，这些种群是由两个不同谱系之间的古老杂交产生的。我们的系统发育和遗传图谱分析表明，XY 系统是在一个与两个不同谱系之间杂交不育相关的大型倒位中形成的。我们认为，在一个杂交种群中，一个新的雄性决定基因在倒位中进化，以应对雄性生育能力受损的选择。鉴于在动物和植物中，倒位通常与杂种不育有关，它们可能经常促成性别决定系统的多样化。
