Data from: Comparative population genomics of latitudinal variation in D. simulans and D. melanogaster

Examples of clinal variation in phenotypes and genotypes across
latitudinal transects have served as important models for understanding
how spatially varying selection and demographic forces shape variation
within species. Here we examine the selective and demographic
contributions to latitudinal variation through the largest comparative
genomic study to date of Drosophila simulans and D. melanogaster, with
genomic sequence data from 382 individual fruit flies, collected across a
spatial transect of 19 degrees latitude and at multiple timepoints over
two years. Consistent with phenotypic studies, we find less clinal
variation in D. simulans than D. melanogaster, particularly for the
autosomes. Moreover, we find that clinally varying loci in D. simulans are
less stable over multiple years than comparable clines in D. melanogaster.
D. simulans shows a significantly weaker pattern of isolation by distance
than D. melanogaster and we find evidence for a strong contribution of
annual re-migration to D. simulans population genetic structure. While
population bottlenecks and migration can plausibly explain the differences
in amount and stability of clinal variation between the two species, we
also observe a significant enrichment of shared clinal genes, suggesting
that the selective forces associated with climate are acting on the same
genes and phenotypes in D. simulans and D. melanogaster.