Population transcriptomics in Daphnia: the role of thermal selection

The complex interplay of forces influencing genetic divergence among populations complicates the discovery of the genetic basis underlying local adaptation. Here, we utilized for the first time a combined reverse ecology and population transcriptomic approach to assess the contribution of thermal selection to population differentiation, thereby considering transcriptome-wide variation in both gene expression profiles and DNA sequences. We compared transcriptomes among four Daphnia galeata populations and identified transcripts potentially responding to local thermal selection based on an extensive literature search for candidate genes possibly under thermal selection in arthropods.
Overrepresentation of temperature-relevant candidate genes among transcripts strongly contributing to sequence divergence among two populations indicates that local thermal selection acted on the coding sequence level. We identified a large number of transcripts which may contribute to local thermal adaptati...