Sex-specific Effects of Hybridization in a Species Lacking Degenerate Sex Chromosomes

在了解物种形成的遗传学方面，大多数进展都是通过对果蝇等模型系统的研究取得的，这些研究特别强调了它们性染色体的特殊作用。更全面的理解需要对其他系统进行研究，包括大量缺乏性染色体的物种（大多数植物、软体动物、海洋无脊椎动物和爬行动物）。这项研究结合了繁殖和分子分析方法，对一种潮池无脊椎动物——加利福尼亚虎脚类桡足动物——进行了研究，以研究在没有性染色体的情况下物种形成是如何发生的。预测将被测试，以解决遗传不相容的作用，核和细胞质基因之间的冲突，以及不相容被其他基因掩盖的程度。不育、生存能力和形态差异的遗传基础将被检查，以及该物种中轻度性别特异性的第二代模式的可能性是由类似于在携带性染色体的物种中常见的强烈性别特异性的第一代模式的机制驱动的。这项工作将开发遗传资源（单核苷酸多态性，连锁图谱），这将证明对越来越多的研究人员关注Tigriopus的一系列未来研究有价值。这项研究还具有保护意义：它解决了生物多样性是如何在缺乏性染色体的生物体中产生的。最后，这项研究将加强与不同社区的联系，并将为一名博士后、一名研究生和众多本科生提供专业培训，包括代表性不足的群体的个人。

Most progress in understanding the genetics of speciation has come through work on model systems like Drosophila, with particular emphasis on the special role of their sex chromosomes. A more comprehensive understanding will require studies of alternative systems, including the vast diversity of species lacking sex chromosomes (most plants, mollusks, marine invertebrates and reptiles). This study uses a combination of breeding and molecular assays in a tidepool invertebrate, the copepod Tigriopus californicus, to examine how speciation occurs when there are no sex chromosomes. Predictions will be tested that address the role of genetic incompatibilities, conflict between nuclear and cytoplasmic genes, and the degree to which incompatibilities are masked by other genes. The genetic underpinnings of sterility vs. viability vs. morphological differences will be examined, as well as the possibility that mild sex-specific second-generation patterns in this species are driven by mechanisms similar to those underlying the strong sex-specific first-generation patterns commonly found in species bearing sex chromosomes.This work will develop genetic resources (single nucleotide polymorphisms, a linkage map) that should prove valuable for a range of future studies by the growing community of researchers focusing on Tigriopus. The research also has conservation implications: it addresses how biodiversity is generated in organisms lacking sex chromosomes. Lastly, this research will enhance outreach to diverse communities and will provide professional training for one postdoctoral associate, one graduate student, and numerous undergraduates, including individuals of underrepresented groups.