Dissertation Research: Gene Leakage into a Hybridogenetic Fish of the Genus Poeciliopsis

无性繁殖物种（克隆）被认为是进化的死胡同，因为轻微有害突变的不可逆积累（突变崩溃）。尽管如此，一些无性生物仍然广泛存在。据信有几种机制可以延缓无性系中的突变积累。一种机制是偶尔与相关的有性物种交配，并整合新的基因拷贝，以掩盖或取代突变缺陷。拟议中的研究将检查在无性系的topminnow鱼类（属Poeciliopsis）的基因置换的证据。基因标记（蛋白质和DNA序列）将被检测以澄清无性生殖谱系的起源，并确定其基因组是否包含来自相关有性生殖物种的新基因。既然克隆哺乳动物不再是幻想，科学家们必须寻找自然模型来评估无性生殖的长期和短期风险。拟花鳉属鱼类是研究最广泛的生物之一，具有密切相关的有性和无性形式。拟议的项目建立在对这些鱼类进行遗传、生态和进化研究的40年历史基础上。这项研究将提供一些无性繁殖物种用来规避突变崩溃和避免灭绝的机制的见解。

9902224VrijenhoekAsexually reproducing species (clones) are considered evolutionary dead-ends due to an irreversible accumulation of slightly deleterious mutations (mutational meltdown). Despite this expectation, some asexual organisms are widespread and abundant. Several mechanisms are believed to retard mutational accumulation in an asexual lineage. One mechanism is to occasionally mate with a related sexual species and incorporate new gene copies that mask or replace mutational defects. The proposed studies will examine evidence for gene replacements in asexual lineages of topminnow fishes (genus Poeciliopsis). Genetic markers (protein and DNA sequences) will be examined to clarify the origin of the asexual lineage, and establish whether its genome contains novel genes from a related sexual species.Now that cloning of mammals is no longer a fantasy, scientists must look to natural models to assess the long- and short-term risks of asexual reproduction. Fish of the genus Poeciliopsis are among the most extensively studied organisms with closely related sexual and asexual forms. The proposed project builds on a 40-year history of genetic, ecological, and evolutionary studies with these fish. This study will provide insights on mechanisms that some asexual species use to circumvent mutational meltdown and avoid extinction.