DISSERTATION RESEARCH: Origins of Parthenogenesis in the Common Checkered Whiptail

有性生殖的主要优势之一是它能够产生和维持生物多样性，然而有些物种是无性繁殖的。该项目将研究单性蜥蜴的克隆繁殖能力，以产生遗传多样性。单性蜥蜴是唯一一种无需雄性输入就能繁殖的脊椎动物。了解单性群体的进化轨迹将有助于确定为什么性是多细胞生命普遍的繁殖模式。该项目的成果和发现将通过以下方式与更广泛的社区建立联系：1)促进培训和指导；2)澄清在分类上受到挑战的物种复杂中的物种水平关系；3)通过与墨西哥研究人员的国际合作促进知识专长的交流。利用新兴的基因组方法，独特的蜥蜴模型，以及一个国际研究团队的才能，该项目解决了一个关于有性生殖的进化和维持的持久进化问题。该项目的目标是确定在克隆繁殖的蜥蜴中形成生物多样性的进化过程。大多数脊椎动物物种通过有性繁殖来维持遗传变异，但一些全雌性蜥蜴通过克隆自己来繁殖没有雄性；母亲生下的女儿的基因组几乎完全相同。然而，克隆是不完美的，因为个体可能不会产生基因相同的克隆由于突变。为了研究是什么在克隆中产生多样性（包括表型多样性），该项目使用来自一个单性生殖的全雌性物种及其相关的有性物种的DNA序列，以确定在开始后的多个创始事件或遗传机制是否能最好地解释表型多样性。将全基因组基因分型与对整个线粒体基因组进行测序的新方法相结合，这些数据将允许对孤雌生殖物种的起源有一个清晰的了解，并推断有性物种之间的物种水平关系。本研究将研究克隆繁殖蜥蜴产生多样性的突变过程的速度和模式，从而深入了解脊椎动物雌雄同体的起源和进化。

One of the primary advantages of sexual reproduction is its ability to generate and maintain biodiversity, yet some species reproduce clonally. This project will address the ability of clonal reproduction to generate genetic diversity in unisexual lizards, the only group of vertebrates capable of reproducing without any input from males. Understanding the evolutionary trajectories of unisexual populations will help identify why sex is the prevalent mode of reproduction for multicellular life. Results and discoveries from this project will connect with the broader community by: 1) promoting training and mentoring, 2) clarifying species level relationships in a taxonomically-challenged species complex, and 3) facilitating exchange of intellectual expertise via international collaborations with Mexican researchers. Using emerging genomic approaches, unique lizard models, and the talents of an international team of researchers, this project addresses a persistent evolutionary question about the evolution and maintenance of sexual reproduction.The goals of this project are to identify the evolutionary processes that shape organismal diversity in a clonally-reproducing lizard. Most vertebrate species maintain genetic variation by reproducing sexually, but several all-female lizards reproduce without males by cloning themselves; mothers beget daughters whose genomes are all but identical. However, cloning is imperfect, as individuals may not produce genetically-identical clones due to mutation. To investigate what generates diversity (including phenotypic diversity) among clones this project uses DNA sequence from one parthenogenetic, all-female species and its related sexual species to determine if either multiple founding events or genetic mechanisms after inception best explain the diversity in phenotypes. Combining genome-wide genotyping with a novel approach to sequence entire mitochondrial genomes, these data should permit a clear picture into the origins of the parthenogenetic species and infer species level relationships among the sexual species. This research will investigate the tempo and mode of mutation processes generating diversity in a clonally-reproducing lizard, thus providing insight into the origins and evolution of unisexuality in vertebrates.