Two uses of DNA sequence variation in tracing evolutionary processes in Old World primates (Primates: Catarrhini)

Primate evolution is particularly interesting to humans, because it includes our own history. Molecular genetics is by far the most dynamic field in contemporary biology, and offers a host of new techniques for investigating evolutionary processes and patterns. In the mid-twentieth century molecular genetics evolved from being a means of visualising hidden variation (e.g. allozymes) to tracing phylogenetic relationships between and among species (evolutionary histories of populations), and now has a wide variety of applications in medicine, species identification and relationships, and even wildlife forensics. For my Master’s project I investigated two applications of molecular genetic analysis to questions regarding the evolution of Old World monkeys (Catarrhini). First, I participated in a study designed to test the hypothesis that different primate social structures – particularly mating systems – may be reflected in the structure of a species genome. We investigated whether increased sperm production as a result of sexual selection increases the number of copy number variations (CNVs) that can be detected by comparing the male specific region Y (MSY) located on the Y chromosome in a sample of primate species. We did not find a clear differentiation between the primate species as hypothesised, which thus requires a more complex explanation, e.g. in terms of the type of environment rather than the mating system of the species, or possibly the active/inactive status of the genes. The second part of my study was phylogeographic in approach. I collaborated with researchers studying the distribution of Afromontane samango monkeys (Cercopithecus albogularis labiatus) in the Eastern Cape. I sequenced tissues from 5 samango monkey specimens found opportunistically in the Hogsback and coastal forests and analysed their genetic variation relative to the data published by Dalton et al. 2015. The Hogsback sample was not monophyletic relative to the sample from the coastal forests, indicating that, on the basis of this very small sample size, these populations have not been separated historically. In order to validate this conclusion, I will need to investigate a larger sample size. From this study I developed valuable skills in the areas of the laboratory techniques involved in molecular sequence analysis, and an appreciation for the importance of large sample sizes in deriving reliable results. I intend to continue in the future with a phylogeographic study of samango monkeys