Genomic impact of transition to asexuality in hybrids

基因组的内容和组织在动物中是非常动态的，破译这种变化背后的机制对于理解进化和生物多样性是如何产生的至关重要。有性生殖是动物基因组进化中最有益的力量之一，但有些动物仍然是无性生殖。无性生物不能从有性繁殖的积极影响中获益，因此预计会积累有害的突变并最终灭绝。我和我的学生将研究两种加拿大鱼类，mummichog （Fundulus heteroclitus）和带状鳉鱼（Fundulus diaphanus）以及它们有性繁殖和无性繁殖的杂交品种。我们将首先通过比较新收集的个体和20多年前收集的样本来确定它们的无性杂交是否暂时稳定。然后，我们将检查有性和无性杂交的基因组，以调查它们的基因组与mummichog和带状鳉鱼相比是否以及如何不同。最后，我们将确定与有性繁殖的杂交种和亲本物种相比，无性杂交种是否积累了更多的有害突变。总之，这些方法将帮助我们理解基因组是如何进化的，有性生殖是如何有益于生物体的，以及为什么有性生殖如此普遍。十名本科生和研究生以及一名研究助理将在本研究项目中接受培训。来自我们工作的出版物将有助于理解生物多样性是如何产生和维持的，并使大量寻求破译基因组进化机制的进化生物学家受益。

Genome content and organization are extremely dynamic across animals and deciphering the mechanisms underlying this variation is critical to understand evolution and how biodiversity is generated. Sexual reproduction is one of the most beneficial forces acting on animal genome evolution, but some animals nevertheless reproduce asexually. Asexual organisms do not benefit from the positive impact of sexual reproduction and are thus expected to accumulate deleterious mutations and eventually go extinct. My students and I will examine two species of Canadian fish, the mummichog (Fundulus heteroclitus) and the Banded Killifish (Fundulus diaphanus) and their sexually and asexually reproducing hybrids. We will first determine whether their asexual hybrids are temporarilly stable by comparing freshly collected individuals to samples that were collected over two decades ago. We will then examine the genomes of sexual and asexual hybrids to investigate whether and how their genomes differ compared to the mummichog and the Banded Killifish. Finally, we will determine whether asexual hybrids accumulate more deleterious mutations compared to sexually reproducing hybrids and parental species. Together, these approaches will help us understand how genomes evolve, how sexual reproduction benefits organisms and why sexual reproduction is so widespread. Ten undergraduate and graduate students as well as one research assistant will be trained over the course of this research program. Publications stemming from our work will help understand how biodiversity is generated and maintained, and benefit the large community of evolutionary biologists that seeks to decipher the mechanisms underlying genome evolution.