Positive Selektion in Drosophila melanogaster

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The Drosophila melanogaster populations in the ancestral species range in Africa are considerably differentiated from the derived populations outside Africa. The colonization of the temperate regions outside Africa occurred relatively recently (for instance, in western Europe about 5000 years ago). Using the hitchhiking effect, we are studying the adaptive process associated with this “out-of-Africa” migration. That is, we seek to identify regions along the genome in which nucleotide variation is reduced through the recent occurrence of beneficial substitutions (“selective sweeps”). Specifically, we propose to re-sequence a newly collected sample of a European population of D. melanogaster using next-generation sequencing (NGS) technology. Together with available polymorphism data from Africa, Asia and North America, this will allow us to infer the recent demographic history of this species in a comprehensive way using Bayesian methods. Furthermore, we will be able to identify the genes that have been the target of positive selection in the adaptation of D. melanogaster populations to their new environments outside Africa. In particular, we investigate the genetic basis of adaptation to the temperate climate by fine-mapping quantitative trait loci (QTL) for cold tolerance by selective sweep analysis.