Genetic basis of iris pigmentation in pigeons

Birds exhibit striking variation in eye color, which arises from interactions between a variety of specialized pigment cells, named chromatophores. The types of chromatophores present in the avian iris are lacking from the integument of birds or mammals, but are remarkably similar to those found in the skin of ectothermic vertebrates. To elucidate the molecular mechanisms associated with eye coloration in birds, we took advantage of a Mendelian mutation that exists in domestic pigeons, that alters the deposition of yellow pterin pigments in the iris. In this study, we used a combination of genetic, genomic and gene expression analyses to reveal the molecular mechanism underlying eye color variation in the domestic pigeon.