Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN, USA; Bell Museum of Natural History, University of Minnesota, Minneapolis, MN, USA.
Mol Ecol Resour. 2014 Sep;14(5):902-13. doi: 10.1111/1755-0998.12237. Epub 2014 Mar 7.
A major barrier to evolutionary studies of sex determination and sex chromosomes has been a lack of information on the types of sex-determining mechanisms that occur among different species. This is particularly problematic in groups where most species lack visually heteromorphic sex chromosomes, such as fish, amphibians and reptiles, because cytogenetic analyses will fail to identify the sex chromosomes in these species. We describe the use of restriction site-associated DNA (RAD) sequencing, or RAD-seq, to identify sex-specific molecular markers and subsequently determine whether a species has male or female heterogamety. To test the accuracy of this technique, we examined the lizard Anolis carolinensis. We performed RAD-seq on seven male and ten female A. carolinensis and found one male-specific molecular marker. Anolis carolinensis has previously been shown to possess male heterogamety and the recently published A. carolinensis genome facilitated the characterization of the sex-specific RAD-seq marker. We validated the male specificity of the new marker using PCR on additional individuals and also found that it is conserved in some other Anolis species. We discuss the utility of using RAD-seq to identify sex-determining mechanisms in other species with cryptic or homomorphic sex chromosomes and the implications for the evolution of male heterogamety in Anolis.
性别的决定机制和性染色体的进化研究一直受到缺乏有关不同物种中发生的性别决定机制类型的信息的阻碍。在鱼类、两栖动物和爬行动物等大多数物种缺乏视觉异型性染色体的群体中，这尤其成问题，因为细胞遗传学分析将无法识别这些物种的性染色体。我们描述了使用限制位点相关 DNA（RAD）测序或 RAD-seq 来鉴定性别特异性分子标记，然后确定一个物种是否具有雄性或雌性异型性。为了测试该技术的准确性，我们研究了蜥蜴 Anolis carolinensis。我们对七个雄性和十个雌性 A. carolinensis 进行了 RAD-seq，发现了一个雄性特异性的分子标记。先前已经表明，A. carolinensis 具有雄性异型性，并且最近发表的 A. carolinensis 基因组促进了性别特异性 RAD-seq 标记的特征描述。我们使用 PCR 在其他个体上验证了新标记的雄性特异性，并且还发现它在一些其他 Anolis 物种中是保守的。我们讨论了使用 RAD-seq 来鉴定具有隐性或同型性染色体的其他物种中的性别决定机制的效用，以及它对 Anolis 雄性异型性进化的影响。
