Sex is a fundamental trait determined by environmental and/or genetic factors, including sex chromosomes. Sex chromosomes are studied in species scattered across the tree of life, yet little is known about tempo and mode of sex chromosome evolution among closely related species. Here, we examine sex chromosome evolution in the adaptive radiation of cichlid fishes in Lake Tanganyika. Through the analysis of male and female genomes from 244 cichlid taxa (189 described species with 5 represented with two local variants/populations; 50 undescribed species) and of 396 multitissue transcriptomes from 66 taxa, we identify signatures of sex chromosomes in 79 taxa, involving 12 linkage groups. We find that Tanganyikan cichlids have the highest rates of sex chromosome turnover and heterogamety transitions known to date. We show that sex chromosome recruitment is not at random. Moreover convergently emerged sex chromosomes in cichlids support the “limited options” hypothesis of sex chromosome evolution.

中文翻译：

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慈鲷快速辐射中性染色体进化动力学

性别是由环境和/或遗传因素（包括性染色体）决定的基本特征。性染色体在分散在生命之树的物种中进行了研究，但对密切相关物种中性染色体进化的速度和模式知之甚少。在这里，我们研究了坦噶尼喀湖慈鲷鱼类适应性辐射中的性染色体进化。通过分析来自 244 个慈鲷类群（189 个已描述物种，其中 5 个代表两个局部变异/种群；50 个未描述物种）的雄性和雌性基因组以及来自 66 个分类群的 396 个多组织转录组，我们确定了 79 个分类群中性染色体的特征，包括12个联动组。我们发现坦噶尼喀慈鲷的性染色体周转率和迄今为止已知的异配子转换率最高。我们表明，性染色体的招募不是随机的。此外，慈鲷中聚合出现的性染色体支持了性染色体进化的“有限选择”假设。