Baboon Endogenous Virus (Baev) variation in natural populations of Cercopithecine primates (Papio hamadryas, Cercopithecus aethiops).
Author: Uddin, Monica
Awarding University: New York University, USA
Level : PhD
Holding Libraries: University Microfilms International ;
Advisors: Adviser: Jolly, CliffordAbstract:
The following study was undertaken to investigate the evolutionary significance of Transposable Element (TE) activity in mammalian hybrids. The specific aims of this work were twofold: (1) to assess the relationship between a particular te, Baboon Endogenous Virus (Baev), and reproductive isolation in a graded series of papionin hybrids and (2) to evaluate endogenous retroviral dynamics in natural primate populations. Baev nucleotide sequence data, quantitative real-time pcr data, and baev nucleotide sequence insertion site data were collected from wild-caught baboons (Papio hamadryas ssp) from Awash National Park (ANP), Ethiopia. Quantitative data were also collected from wild-caught baboons from Masai Mara, Kenya, as well as a number of captive baboons, f<sub>1</sub> hybrids, and geladas. Additional baev sequence data were collected from ANP wild-caught grivets (Cercopithecus aethiops). Results indicate a non-uniform pattern of Baev amplification across hybrids of varying phylogenetic distance: whereas backcrossed baboon and f<sub>1</sub> 'rheboon' (Macaca mulatta × P. H. Hamadryas) hybrids showed no evidence of copy number amplification, the f<sub>1</sub> 'geboons' (Theropithecus gelada ×P. H. Hamadryas) hybrids did. This finding refutes the hypothesis that hybridization-related baev amplification is correlated with actual or potential reproductive isolation, as the rheboon represents the only confirmed case of hybrid sterility. Baev sequence data suggest a non-uniform rate of evolution across the proviral genome: those areas that encode proteins external to the mature virion show a greater degree of sequence divergence and/or nonsynonymous substitution than those that encode proteins with more conserved functions. Insertion site data confirm a pattern of vertical inheritance in the four baboon forms tested, suggesting long-term residence in the Papio genome. Baev shows considerable copy number heterogeneity among individuals yet conforms to a pattern of maternal inheritance previously observed for endogenous retroviruses in other organisms. Most importantly, average proviral copy numbers in non-hamadryas, hamadryas and gelada baboons, respectively, appear to be a function of the progressively greater degrees of inbreeding observed in each of these primate taxa. This finding represents the first example in primates relating transposon dynamics to social structure and suggests that element number may be regulated though a mechanism of ectopic exchange rather than deleterious selection.