Pigeonetics takes flight: Evolution, development, and genetics of intraspecific variation

- Domestic rock pigeons display dramatic variation within a single species.
- Pigeons are amenable to genetic, genomic, and developmental studies of diversity.
- The molecular basis for several classic traits is now known.
- Variation in pigeons is relevant to other evolutionary and biomedical phenotypes.
- Pigeons can reveal general mechanisms of avian and vertebrate diversity.

Intensive artificial selection over thousands of years has produced hundreds of varieties of domestic pigeon. As Charles Darwin observed, the morphological differences among breeds can rise to the magnitude of variation typically observed among different species. Nevertheless, different pigeon varieties are interfertile, thereby enabling forward genetic and genomic approaches to identify genes that underlie derived traits. Building on classical genetic studies of pigeon variation, recent molecular investigations find a spectrum of coding and regulatory alleles controlling derived traits, including plumage color, feather growth polarity, and limb identity. Developmental and genetic analyses of pigeons are revealing the molecular basis of variation in a classic example of extreme intraspecific diversity, and have the potential to nominate genes that control variation among other birds and vertebrates in general.