REDNESS VARIATION IN THE EURASIAN SCOPS-OWL OTUS SCOPS IS DUE TO PHEOMELANIN BUT IS NOT ASSOCIATED WITH VARIATION IN THE MELANOCORTIN-1 RECEPTOR GENE (MC1R)

Melanin-based colorations in birds constitute a paradigm for the study of the molecular basis of phenotypic variation. Variation in the mclanocortin-1 receptor (MCR1) gene, a key regulator of melanin synthesis in feather melanocytes, can lead to changes in the production of melanin and hence in feather colour. Here we investigate the proximate mechanisms behind colour plumage polymorphism in the Eurasian Scops-owl Otus scops, a species showing pronounced variation in the degree of redness. Although eumelanin pigment was three times more abundant than pheomelanin pigments, the degree of plumage redness was more strongly associated with the amount of pheomelanin than eumelanin pigments. We detected only one synonymous substitution and one non-synonymous substitution in MC1R which were, however, not associated with variation in plumage coloration. Redness variation in Eurasian Scops-Owls is primarily due to variation in pheomelanin, and to genes or regulatory elements other than MCR1.