Doctoral Dissertation Improvement: Genetic Transposition of Baboon Endogenous Virus (BaEV) in Hybrid Old World Monkeys (Primates: Papionini)

New York University, New York NY

Investigators

Abstract

More than 14 decades after the publication of "On the Origin of Species," the processes leading to the appearance and genetic stabilization of new, consistently distinct populations remains one of the least understood of evolutionary processes. While a variety of mechanisms may be associated with genetic isolation, attention recently has focussed upon genome-level features that are both rapidly-evolving and can drastically reduce the ability of their carriers to interbreed and produce viable hybrid offspring. A variety of recent evidence implicates transposable elements (TEs) in facilitating such reproductive isolation. TEs are small (100-10kb base pairs) genetic elements that have retained their ability to move about within genomes. Investigations conducted on organisms as diverse as fruit flies and wallabies suggest that there is a positive correlation between transposable element activity and sterility in inter-strain hybrids. In order to determine how TE-mediated barriers to inter-population hybridization might evolve, it is necessary to examine the behavior of such elements in fertile hybrids and their progeny in naturally occurring hybrid zones. The goal of this project is to investigate the relationship between TE amplification and hybridity by testing for evidence of baboon endogenous virus (BaEV) transposition in a graded series of Old World Monkey hybrids in the papionin group. BaEV is an endogenous retrovirus that was once transmitted horizontally from individual to individual but now forms an integrated part of the vertically inherited genome of many Old World Monkeys. Retroviruses are one of the most complex TE forms, with large genomes that can generate copies through the intrinsically driven process of reverse transcription. This project will thus investigate the relationship between TE activity and reproductive isolation by testing BaEV amplification in papionin hybrids with varying degrees of hybrid ancestry. The specific aims of the proposed research are: to determine the degree to which BaEV amplification is correlated with hybrid sterility; to determine the degree to which BaEV amplification increases in hybrid papionins with increased evolutionary distance between parental taxa; to detect novel BaEV integrations in individuals with known parentage that may be attributable to specific hybridization events; and to determine the extent of BaEV sequence variation in a wild primate population. These objectives will be accomplished by sampling a graded series of hybrid papionins reflecting different degrees of hybrid ancestry. These data will serve as a first step in determining the contribution of TEs to reproductive isolation in papionins.