Effects of Female Gene Flow and Effective Population Size on Old and New World Mitochondrial DNA Patterns
thesisposted on 15.04.2014 by Ken Batai
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The goal of this dissertation project is to examine the effects of female gene flow and female effective population size on mtDNA variation. I examined 1) whether the Aymara and Bantu expanded mainly through spatial expansion by incorporating female migrants from other ethnic groups or through demographic expansion due to increased female fertility rates, 2) whether female gene flow or effective population size had the greater effect on mtDNA within-population genetic diversity, and 3) the extent to which kinship structure affected the importance of each factor. The results of the analyses suggest rapid demographic expansion best explains Aymara population expansion. Female gene flow was also an important factor influencing mtDNA variation in Central Andeans as well as western South America, but female gene flow had a much greater impact on mtDNA variation among east African Bantu populations. The east African Bantu populations interacted extensively with neighboring non-Bantu populations. As a result, the east African Bantus became genetically more diverse and similar to some non-Bantu east Africans. Closer examination of the impact of female gene flow and effective population size reveals that female gene flow affects within-population genetic diversity measurements and genetic models that do not account for population subdivision and gene flow are poor fits to the observed mtDNA data. In addition, kinship structure is an important cultural practice that affects the patterns and intensity of female gene flow and is a good predictor of within-population genetic diversity and population subdivision. In conclusion, this dissertation project shows that female effective population is an important factor, but female gene flow had a great impact on mtDNA variation among Latin Americans and Bantus affecting their within-population genetic diversity and patterns of population subdivision.