Color phenotypes are under similar genetic control in two distantly related species of Timema stick insect

Ecology and genetics are both of general interest to evolutionary biologists as they can influence the phenotypic and genetic response to selection. The stick insects Timema podura and T. cristinae exhibit a green/melanistic body color polymorphism that is subject to different ecologically-based selective regimes in the two species. Here we describe aspects of the genetics of this color polymorphism in T. podura, and compare this to previous results in T. cristinae. We first show that similar color phenotypes of the two species cluster in phenotypic space. We then use genome-wide association mapping to show that in both species, color is controlled by few loci, dominance relationships between color alleles are the same, and SNPs associated with color phenotypes co-localize to the same linkage group. Regions within this linkage group that harbor genetic variants associated with color exhibit elevated linkage disequilibrium relative to genome wide expectations, but more strongly so in T. ...