The impact of endoparasitic Wolbachia on the evolution of reproductive barriers during speciation in Drosophila ananassae from Southeast Asia and the South Pacific

UNCG Author/Contributor (non-UNCG co-authors, if there are any, appear on document)
Austin N. Craven (Creator)
The University of North Carolina at Greensboro (UNCG )
Web Site:
Malcolm Schug

Abstract: There is still much work to be done in Biology to study and understand the mechanisms that drive the generation of new species. The model organism Drosophila ananassae represents and ideal model to untangle these issues. Previous genetic and mate discrimination studies of D. ananassae showed evidence that populations in Southeast Asia, and the South Pacific may be at a nascent stage of speciation (Schug et al. 2007, 2008). Subsequent preliminary studies demonstrated a potential postmating isolation barrier may exist between Bogor, Indonesia isofemale line 13 (BOG13) and females from Trinity Beach, Australia isofemale line 12 (TB12), which when hybridized and backcrossed to BOG13 females showed a decrease in offspring production. This may reflect a genetic isolation barrier, or alternatively, the effects of infection of one population or the other with endoparasite Wolbachia which is known in other organisms to cause postmating reproductive barriers. My study tested the hypothesis that the postmating barrier present between these two populations is driven by Wolbachia infection. I found that TB12 was infected with Wolbachia and BOG13 was not. A full reciprocal backcross preformed between these isofemale lines, and replicate using a TB12 isofemale line cured of the Wolbachia infection, revealed results consistent with Wolbachia-induced cytoplasmic incompatibilities (CI), that were removed when cured of the Wolbachia infection. A screen of additional strains previously shown to have high levels of mate discrimination showed the possibility that Wolbachia infection may have influenced the evolution of postmating reproductive barriers in additional populations of D. ananassae from throughout Southeast Asia and South Pacific. However, my mate discrimination experiments using infected versus cured isofemale lines from Bogor, Indonesia and Trinity Beach, Australia indicated that it is unlikely that Wolbachia infections directly influence mate discrimination behaviors, but are likely having an influence on postmating reproduction. Taken together this suggests that Wolbachia infections in populations of D. ananassae throughout its range in Southeast Asia and the South Pacific may have a significant influence on population divergence and speciation.

Additional Information

Language: English
Date: 2013
Ananassae, Evolution, Population genetics, South Pacific, Speciation, Wolbachia
Drosophila ananassae $z Southeast Asia $x Genetics
Drosophila ananassae $z Oceania $x Genetics
Drosophila ananassae $z Southeast Asia $x Reproduction
Drosophila ananassae $z Oceania $x Reproduction
Wolbachia $z Southeast Asia
Wolbachia $z Oceania

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