Meeting Abstract

19.6  Thursday, Jan. 3  Why does genetic diversity of mitochondrial genes not reflect population size? KNOTT, K. E.; University of Jyvaskyla, Finland emily.knott@bytl.jyu.fi

According to neutral theory, the amount of genetic variation within a population will be positively correlated with population size. However, according to a recent analysis by Bazin and colleagues (Science 312:570-572), mitochondrial DNA diversity does not vary appreciably among different animal groups with inferred differences in population size, whereas the expected relationship can be observed for nuclear DNA diversity and allozymic heterozygosity. This finding emphasizes important questions about the suitability of mitochondrial DNA as a neutral marker, and the authors propose that recurrent adaptive evolution in the mitochondrial genome has led to the observed pattern. Possible effects of selection in the mitochondrial genome should be taken into consideration, but the pattern observed by Bazin and colleagues may have been affected by other factors. Here, I investigate the effects of population differentiation on genetic diversity estimates. Since differentiation among populations is likely first observed in the mitochondrial genome, population level variation in nucleotide frequencies may artificially inflate diversity estimates and skew Tajima�s D to negative values when the data from differentiated populations are combined. An analysis based on datasets from population-based studies will be presented in comparison to analyses based on blind data-mining and phylogeographic studies. This analysis relies on more information than is typically provided in GenBank records, namely, information about population sampling and structure recorded in the primary literature.