Anthropology

Deven N. Vyas Dissertation Defense:
Friday, July 7^th, 9:00 am
Cancer & Genetics Research Complex 133
Title: Genetic Inferences on Human Evolutionary History in southern Arabia and the Levant
Abstract:
In this dissertation, I study genetic variation in Levantine and southern Arabian populations in order to study human evolutionary history in these regions. The Levant and southern Arabia are the proposed starting points of the successful dispersal out of Africa, along the hypothesized North Dispersal Route (NDR) and Southern Dispersal Route (SDR), respectively.
In my first study, I test whether Yemeni mitogenomic diversity is the product of recent or ancient migrations. I generate 113 novel Yemeni mitogenome sequences, which were primarily selected from haplogroups capable of detecting more ancient migrations. Using Bayesian phylogenetic analyses, I find that Yemeni variation is largely the product of recent migrations from different regions and recent in situ evolution. In my second study, I test support for the NDR and SDR by analyzing genotyping data from single nucleotide polymorphisms (SNPs) from Levantine and southern Arabian populations. I generate novel genotyping data from >600,000 SNPs from 90 Yemeni selected from all across Yemen, which I analyze alongside published data from >160 populations. Using measures of shared genetic drift, I find that Levantine and southern Arabian populations are similarly related to test African and non-African populations. I conclude that neither the route can be supported or rejected due to extensive gene flow between the Levant and southern Arabia. In my third study, I compare Neanderthal introgression in Levantine and southern Arabia populations to infer where introgression first occurred. Using statistical measures of introgression, I find that Levantine and southern Arabian populations have similar levels of introgression to each other but lower levels than other non-Africans. I also find that introgressed SNPs have similar frequencies in the Levant and southern Arabia, indicating that introgression is similarly distributed in Levantine and southern Arabian genomes. I infer that Levantine and southern Arabian populations received introgression before separating from each other and that there has been extensive gene flow between these regions.
From these three studies, I find that gene flow between the Levantine and southern Arabian populations has shaped these regions’ genetic diversity. This dissertation highlights the value of using genetic variation to make inferences about populations’ evolutionary histories.
Committee:
Chair: Connie J. Mulligan
Members: Steven A. Brandt, John Krigbaum
External Member: David L. Reed (FLMNH)