Admixture mapping in a hybrid zone reveals loci associated with avian feather coloration

Identifying the genetic bases for color patterns has provided important insights into the control and expression of pigmentation and how these characteristics influence fitness. However, much more is known about the genetic bases for traits based on melanin pigments than for traits based on another major class of pigments, carotenoids. Here we use natural admixture in a hybrid zone between Audubon’s and myrtle warblers (Setophaga coronata auduboni / S. c. coronata) to identify genomic regions associated with both types of pigmentation. Warblers are known for rapid speciation and dramatic differences in plumage. For each of five plumage coloration traits, we found highly significant associations with multiple SNPs across the genome and these were clustered in discrete regions. Regions near significantly associated SNPs were enriched for genes associated with keratin filaments, fibrils that makeup feathers. A carotenoid-based trait that differs between the taxa—throat color—had more than ...