Doctoral Dissertation Improvement: Nucleotide Substitution Rate Variation in the Catarrhini (Order Primates)

本研究解决了分子进化研究中的一个开放性问题：有机体水平特征（如体重、饮食、行为）与分子特征（如DNA进化速度、基因组大小、物种内部和物种之间的DNA变异）之间的联系。具体来说，在世代时间、种群规模、代谢率、体型、自然选择活动和物种特异性的DNA复制准确性差异等方面的差异是如何影响DNA进化速度的？这个项目将通过检验一个被充分研究过的物种群体中DNA进化速率的差异来增加对科学的理解。研究将集中在灵长类动物，哺乳动物群体，包括人类，类人猿和旧大陆猴，因为它们在生活史变量，生物学和生态学方面具有显著且可测量的差异。此外，有强有力的证据表明，这一群体的DNA进化速度存在差异，因为有证据表明，人类和类人猿的DNA进化速度比旧大陆的猴子慢。先前的研究调查了DNA进化速率的变化，已经检查了大量的DNA序列样本，但是在一组有限的远亲物种中——例如，人类、老鼠和牛。这项研究的不同之处在于，在一个相对密切相关的灵长类动物的广泛样本中，取样了一组10个独立的基因座。选择这些位点代表蛋白质编码和非编码（内含子、假基因和基因间）序列。最终，这个项目将有助于研究进化的方式、时间和原因，特别是当它与灵长类动物和人类进化有关时。结果可能告诉我们：-现代旧大陆的猴子物种是如何相关的？现代猿类谱系是什么时候分化的？科洛比猴是如何以及何时在解剖学上变得专门吃树叶的？人类的祖先是什么时候从最终进化为黑猩猩的谱系中分化出来的？这是一个博士论文的改进项目，不可分割的共同研究者的研究生培训。研究成果将发表在学位论文和学术论文中，并在学术会议上发表。在研究过程中获得的DNA序列将存储在由国家生物技术信息中心（NCBI）托管的可公开访问的GenBank数据库中。

This research addresses an open issue in the study of molecular evolution: The connection between organismal level features (e.g. weight, diet, behavior) and molecular traits (e.g. rate of DNA evolution, genome size, DNA variation within and between species). Specifically, how do differences in generation time, population size, metabolic rate, body size, the activity of natural selection, and species-specific differences in DNA replication accuracy affect the rate of DNA evolution? This project will add to scientific understanding by examining DNA evolutionary rate differences within a well-studied group of species.The research will focus on the catarrhine primates, the mammalian group which includes humans, apes, and Old World monkeys, as they have significant and well-measured differences in life history variables, biology, and ecology. Furthermore, there is strong evidence for variation in the rate of DNA evolution within this group as there is evidence suggesting that humans and apes exhibit a slower rate of DNA evolution than the Old World monkeys. Previous studies investigating variation in the rate of DNA evolution have examined a broad sample of DNA sequences, but in a limited set of distantly related species - for example, human, mouse, and cow. This research differs by sampling a set of 10 independent loci in an extensive sample of relatively closely related catarrhine primates. The loci were chosen to represent protein coding and non-coding (introns, pseudogenes and intergenic) sequences. Ultimately, this project will contribute to the study of the how, when, and why of evolution, particularly as it pertains to primate and human evolution. The results may inform us as to: -How are the modern day Old World monkey species related? -When did the modern lineages of apes diverge? -How and when did the colobine monkeys become anatomically specialized for leaf eating? -When did the ancestors of humans become differentiated from the lineage ultimately leading to the chimpanzee?This is a doctoral dissertation improvement project integral to the co-investigator's graduate training. The research results will be published in a dissertation and scholarly papers, as well as presented at academic conferences. The DNA sequences obtained in the course of the study will be deposited in the publicly accessible GenBank database hosted by the National Center for Biotechnology Information (NCBI).