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

在理解物种形成的遗传学方面，大多数进展是通过对果蝇等模型系统的研究取得的，特别强调了它们的性染色体的特殊作用。更全面的理解将需要研究替代系统，包括缺乏性染色体的物种的巨大多样性(大多数植物、软体动物、海洋无脊椎动物和爬行动物)。这项研究使用繁殖和分子分析相结合的方法，对潮间带无脊椎动物--剑齿虎足目动物--进行研究，以研究在没有性染色体的情况下物种形成是如何发生的。将对解决遗传不亲和性的作用、核基因和细胞质基因之间的冲突以及不亲和性被其他基因掩盖的程度的预测进行测试。我们将研究不育、存活和形态差异的遗传基础，以及该物种温和的性别特异性第二代模式可能是由类似于通常在携带性染色体的物种中发现的强烈性别特异性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，连锁图谱)，这将被证明是有价值的，由越来越多的研究人员专注于老虎的一系列未来研究。这项研究还具有保护意义：它阐述了生物多样性是如何在缺乏性染色体的有机体中产生的。最后，这项研究将加强对不同社区的接触，并将为一名博士后助理、一名研究生和许多本科生提供专业培训，包括代表人数不足的群体的个人。

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.