The evolution of insects in changing environments: From population genetics to host-symbiont interactions
Natural History Museum Vienna, Vienna, Austria
Clines, which are gradual changes of genotypes or phenotypes along environmental transects, are often taken as prima facie evidence for the action of spatially varying selection. However, only due to recent advances in sequencing technology it now becomes possible to compare genome-wide clinal patterns and test for alternative models. We accordingly conducted genome-wide analyses of clinal genomic variation in D. melanogaster densely sampled through time and space on different continents and tested for associations between genetic and environmental variation. These analyses reveal complex demographic patterns and pronounced clinal genetic variation along different geographical and environmental transects. Multiple clinal variants, including chromosomal inversions are shared across continents. In particular, we find evidence for steep and temporally stable clinal variation strongly associated with In(3R)Payne, a common cosmopolitan inversion, which has a genome-wide impact on genetic variation, expression patterns and phenotypic variation. In addition, we investigated how the bacterial endosymbiont Wolbachia influences thermal behavior and affects fitness-related traits in a temperature-dependent manner, which may contribute to complex patterns of thermal adaptation of the host.
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