PgmNr P317: Parallel Gene Expression Differences between Low and High Latitude Populations of two Drosophila species.

Authors:
Li Zhao; David J. Begun


Institutes
Department of Evolution and Ecology, UC Davis, Davis, CA.


Abstract:

Gene expression variation within species is relatively common, however, the role of natural selection in the maintenance of this variation is poorly understood. Here we study geographic differences in gene expression in recently established low and high latitude populations of two closely related species of Drosophila, Drosophila melanogaster and D. simulans, to determine whether the two species show similar patterns of population differentiation, consistent with a role for spatially varying selection in maintaining gene expression variation. We observed a significant excess of genes exhibiting differential expression in both species, consistent with parallel adaptation to heterogeneous environments. Moreover, the majority of genes showing parallel expression differentiation showed the same direction of differential expression in the two species and the magnitudes of expression differences between high and low latitude populations were correlated across species, further bolstering the conclusion that parallelism for expression phenotypes results from spatially varying selection. Comparison of inter-population sequence differentiation and expression differentiation suggests that cis-acting variants play a role in geographic expression differentiation.