DISSERTATION RESEARCH: Quantifying the tempo of genome theft in polyploid, female-only Ambystoma salamanders

论文研究：量化多倍体、雌性钝口蝾螈基因组盗窃的速度

• 批准号: 1600655
• 负责人: Harold Gibbs
• 金额: $ 1.75万
• 依托单位: Ohio State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-07-01 至 2017-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1600655&HistoricalAwards=false
• 关键词: DISSERTATION; RESEARCH; Quantifying; tempo; genome

This project will test a hypothesis to explain how a lineage of female-only salamanders has been able to persist for millions of years. Most animals reproduce sexually even though there is a high evolutionary cost of making males. Males compete with females for resources and decrease the genetic resemblance between a female and her offspring. Few animal species reproduce without mating and most only live for a short evolutionary time. However, an all-female lineage of salamanders (the oldest known all-female vertebrate in North American) has been able to persist for approximately 6 million years. Because the persistence of asexual animals is rare, they can provide valuable clues about the costs and benefits of sexual reproduction. Sometimes these female-only salamanders are able to obtain new genetic material from males of closely related species. Thus, they may gain the benefits of both sexual and asexual reproduction. To test this idea, the researchers will measure the importance of genetic contributions from sexual species into the all-female asexual species over evolutionary time. In addition, the project will include the training of undergraduate and graduate students and outreach activities such as museum displays and social blogs. This research will quantify the rate and evolutionary history of genome leakage from sexual species in to the unisexual Ambystoma lineage, which will allow us to test the hypothesis that recurrent genome contribution accounts for the greater lineage age of unisexual Ambystoma as compared to other gynogenetic taxa. The researchers will use genome-scale data and evolutionary demographic modeling to evaluate multiple evolutionary scenarios ranging from no genetic contributions from sexual species, to recent (but limited) genome contributions only, or ongoing genome contributions. This will be accomplished by using custom bioinformatics tools to sort genetic variation among the multiple genomes of unisexual salamanders, comparing this variation to that of the genomes of sexual species thought to be the source of novel genetic variation in unisexuals and then using statistical genetic models to estimate the magnitude and timing of genetic exchange between unisexual and sexual salamanders.

该项目将测试一个假设，以解释只有雌性蝾螈的血统如何能够持续数百万年。大多数动物进行有性繁殖，尽管制造雄性的进化代价很高。雄性与雌性争夺资源，减少雌性与其后代之间的遗传相似性。很少有动物物种不交配就繁殖，大多数动物只活很短的进化时间。然而，蝾螈的全雌性血统（北美已知最古老的全雌性脊椎动物）已经能够持续大约600万年。由于无性繁殖动物的持续性是罕见的，它们可以提供关于有性繁殖的成本和收益的有价值的线索。有时，这些雌性蝾螈能够从近亲物种的雄性蝾螈那里获得新的遗传物质。因此，它们可以获得有性和无性生殖的好处。为了验证这一想法，研究人员将测量在进化过程中有性物种对全雌性无性物种的遗传贡献的重要性。此外，该项目还将包括对本科生和研究生的培训以及博物馆展览和社交博客等外联活动。这项研究将量化的速率和进化历史的基因组泄漏从有性物种的单性Ambystoma谱系，这将使我们能够测试的假设，即经常性的基因组贡献占更大的谱系年龄的单性Ambystoma相比，其他雌核发育类群。研究人员将使用基因组规模数据和进化人口模型来评估多种进化情景，从有性物种没有遗传贡献，到最近（但有限）的基因组贡献，或正在进行的基因组贡献。这将通过使用定制的生物信息学工具来完成单性蝾螈的多个基因组中的遗传变异进行排序，将这种变异与被认为是单性蝾螈中新的遗传变异来源的有性物种的基因组进行比较，然后使用统计遗传模型来估计单性蝾螈和有性蝾螈之间遗传交换的幅度和时间。