Data from: Genomic clustering of adaptive loci during parallel evolution of an Australian wildflower

The buildup of the phenotypic differences that distinguish species has long intrigued biologists. These differences are often inherited as stable polymorphisms that allow the co-segregation of adaptive variation within species. It has been suggested that the clustering of adaptive loci could facilitate this process. Here we tested this possibility by studying the genetic basis of phenotypic differentiation between populations of an Australian wildflower that inhabit adjacent but contrasting coastal environments. For this we created a linkage map and ran QTL analyses in two parapatric populations of Senecio lautus adapted to a sand dune and a rocky headland. We found that a genomic region governs variation in several traits that distinguish the two populations. Additionally, some of the traits controlled by this QTL cluster have evolved repeatedly during the colonization of the same habitats, suggesting that they play an important role in environmental adaptation. Furthermore, this genomic region is associated to field survivorship in reciprocal transplants and show high genetic differentiation between multiple pairs of parapatric populations. Altogether our results support the importance genetic clustering during the rapid diversification of this species.