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

无性繁殖的物种（克隆）被认为是进化的死胡同，因为轻微有害突变（突变熔解）的不可逆积累。尽管有这样的期望，一些无性生物广泛而丰富。有几种机制被认为可以延缓无性谱系中的突变积累。一种机制是偶尔与相关的有性物种交配，并结合新的基因拷贝来掩盖或取代突变缺陷。提出的研究将检查在无性血统的鳍鱼（Poeciliopsis属）基因替换的证据。遗传标记（蛋白质和DNA序列）将被检查以澄清无性谱系的起源，并确定其基因组是否包含来自相关有性物种的新基因。既然克隆哺乳动物不再是一个幻想，科学家们必须着眼于自然模型来评估无性繁殖的长期和短期风险。Poeciliopsis属的鱼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。这项拟议中的项目建立在对这些鱼类进行了40年的遗传、生态和进化研究的基础上。这项研究将提供一些无性物种用来规避突变熔解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.