Data from: Genome-wide association mapping of phenotypic traits subject to a range of intensities of natural selection in Timema cristinae

The genetic architecture of adaptive traits can reflect the evolutionary history of populations and also shape divergence among populations. Despite this central role in evolution, relatively little is known regarding the genetic architecture of adaptive traits in nature, particularly for traits subject to known selection intensities. Here we describe the genetic architecture of traits that are subject to differential selection between host plant species in Timema cristinae stick insects. Specifically, we used phenotypic measurements of 10 traits and 187,110 single nucleotide polymorphisms (SNPs) to conduct multi-locus genome-wide association mapping. We identified a modest number of SNPs that were associated with traits and sometimes explained a large proportion of trait variation. These SNPs varied in their strength of association with traits, and both major and minor effect loci were discovered. Finally, there was some evidence that, after controlling for strength of differential selection, traits underlain by SNPs of larger (versus smaller) average effect size were more strongly differentiated between host-associated populations. Our results provide a first step towards identifying loci underlying adaptation in T. cristinae. Future studies will examine the genomic location, population differentiation, and response to selection of the trait-associated SNPs described here.