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

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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).