Molecular parallelisms between pigmentation in the avian iris and the integument of ectothermic vertebrates

by Pedro Andrade, Ma łgorzata A. Gazda, Pedro M. Araújo, Sandra Afonso, Jacob. A. Rasmussen, Cristiana I. Marques, Ricardo J. Lopes, M. Thomas P. Gilbert., Miguel Carneiro

Birds exhibit striking variation in eye color that arises from interactions between 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 ec tothermic vertebrates. To investigate molecular mechanisms associated with eye coloration in birds, we took advantage of a Mendelian mutation found in domestic pigeons that alters the deposition of yellow pterin pigments in the iris. Using a combination of genome-wide association analysis and linkag e information in pedigrees, we mapped variation in eye coloration in pigeons to a small genomic region of ~8.5kb. This interval contained a single gene,SLC2A11B, which has been previously implicated in skin pigmentation and chromatophore differentiation in fish. Loss of yellow pigmentation is likely caused by a point mutation that introduces a premature STOP codon and leads to lower expression ofSLC2A11B through nonsense-mediated mRNA decay. There were no substantial changes in overall gene expression profiles between both iris types as well as in genes directly associated with pterin metabolism and/or chromatophore differentiation. Our findings demonstrate thatSLC2A11B is required for the expression of pterin-based...

Source: PLoS Genetics - February 23, 2021 Category: Genetics & Stem Cells Authors: Pedro Andrade Source Type: research