RT Journal Article SR Electronic T1 Influence of Two Wolbachia Strains on Population Structure of East African Drosophila simulans JF Genetics JO Genetics FD Genetics Society of America SP 1959 OP 1969 VO 165 IS 4 A1 Dean, Matthew D. A1 Ballard, Kirrie J. A1 Glass, Anne A1 William, J. A1 Ballard, O. YR 2003 UL http://www.genetics.org/content/165/4/1959.abstract AB Drosophila simulans is hypothesized to have originated in continental East Africa or Madagascar. In this study, we investigated evolutionary forces operating on mitochondrial DNA (mtDNA) in populations of D. simulans from Zimbabwe, Malawi, Tanzania, and Kenya. Variation in mtDNA may be affected by positive selection, background selection, demographic history, and/or any maternally inherited factor such as the bacterial symbiont Wolbachia. In East Africa, the wRi and wMa Wolbachia strains associate with the siII or siIII mitochondrial haplogroups, respectively. To ask how polymorphism relates to Wolbachia infection status, we sequenced 1776 bp of mitochondrial DNA and 1029 bp of the X-linked per locus from 79 lines. The two southern populations were infected with wRi and exhibited significantly reduced mtDNA variation, while Wolbachia-uninfected siII flies from Tanzania and Kenya showed high levels of mtDNA polymorphism. These are the first known populations of D. simulans that do not exhibit reduced mtDNA variation. We observed no mitochondrial variation in the siIII haplogroup regardless of Wolbachia infection status, suggesting positive or background selection. These populations offer a unique opportunity to monitor evolutionary dynamics in ancestral populations that harbor multiple strains of Wolbachia.