NSF Postdoctoral Fellowship in Biology FY 2019: Mitochondrial genome architecture as a driver of speciation in parasitic lice

该奖项支持NSF生物学博士后研究奖学金，使用生物收集的研究。该研究金支持研究员的研究和培训，以创新的方式利用生物收藏。大多数动物的线粒体DNA位于一条染色体上。然而，一些寄生虱的线粒体DNA被分离到多个染色体上。目前还不知道如何或为什么这样一个罕见的条件是维持在虱子。该研究员试图通过测试线粒体基因组结构（即单染色体与多染色体）的差异是否与自然选择和物种形成有关来解决这一知识差距，这一过程主要负责产生生物多样性。为此，这位研究员将依靠博物馆收藏品来比较具有多个线粒体染色体的虱子物种的DNA序列和身体测量结果。这项工作将有助于回答生物学中一个特别令人困惑的问题，同时展示产生生物多样性的机制。该项目还将包括在地方和国家范围内促进普通受众的生物多样性的教育内容。该研究员将使用从博物馆标本中获得的多条证据来专门解决破碎的线粒体染色体是否通过线粒体-核不相容性作为物种形成的缓冲区。首先，该研究员将比较两组已知具有不同线粒体结构的鸟类虱子的系统发育多样性，突变率和基因组选择：来自鸽子的翅膀（碎片染色体）和身体（单染色体）虱子。较低的突变率，但更高的多样化，分歧，并在体虱选择将表明，单线粒体染色体促进物种形成。第二，研究员将测试突变率和虱子的神秘物种的选择水平。隐种具有难以区分的形态差异，但在遗传上高度分化。如果对隐蔽体虱物种具有不可分割的形态与高遗传分化和积极选择的签名，而隐蔽翅虱物种没有，这将再次表明，单染色体促进物种形成。该研究员将接受基于形态学的研究和基因组进化方面的广泛培训。该项目还将包括对普渡大学本科生进行分子/生物信息学方法培训的组成部分。此外，工作成果将被纳入课程计划，外展展示，以及专注于进化和生物多样性的教育出版物中。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的知识价值和更广泛的影响审查标准进行评估来支持。

This award supports an NSF Postdoctoral Research Fellowship in Biology, Research Using Biological Collections. The fellowship supports research and training of the fellow that will utilize biological collections in innovative ways. Most animals have mitochondrial DNA on a single chromosome. However, some species of parasitic lice have their mitochondrial DNA separated onto multiple chromosomes. It is not known how or why such a rare condition is maintained in lice. The fellow seeks to address this knowledge gap by testing whether differences in mitochondrial genome architecture (that is, single vs. multiple chromosomes) are linked to natural selection and speciation, the processes largely responsible for generating biodiversity. To this end, the fellow will rely on museum collections to compare DNA sequences and body measurements of lice species that have multiple mitochondrial chromosomes to those that have a single chromosome. This work will help answer a particularly puzzling question in biology while simultaneously showing a mechanism that generates biodiversity. The project will also include educational components that promote biodiversity among general audiences at both local and national scales.The fellow will use multiple lines of evidence obtained from museum specimens to specifically address whether fragmented mitochondrial chromosomes act as a buffer to speciation via mito-nuclear incompatibility. First, the fellow will compare phylogenetic diversity, mutation rates, and genomic selection in two groups of avian lice that are known to have different mitochondrial architectures: wing (fragmented chromosomes) and body (single chromosomes) lice from doves. Lower mutation rates but higher diversification, divergence, and selection in body lice would suggest that single mitochondrial chromosomes promote speciation. Second, the fellow will test mutation rates and levels of selection in cryptic species of lice. Cryptic species have indistinguishable morphological differences but are highly divergent genetically. If pairs of cryptic body louse species have inseparable morphology with high genetic divergence and signatures of positive selection, whereas cryptic wing louse species do not, this would again indicate that single chromosomes promote speciation. The fellow will receive extensive training in morphology-based inquiry and genome evolution. This project will also include a component for training Purdue University undergraduate students in molecular/bioinformatic methods. Additionally, results from the work will be incorporated into lesson plans, outreach displays, and educational publications focused on evolution and biodiversity.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.