A missense mutation in the tyrosinase gene explains acromelanism in domesticated canaries

Abstract

Acromelanism is a form of albinism observed in several vertebrate species. In mammals, acromelanism is known to be caused by mutations in the tyrosinase gene (TYR) that induce a temperature-sensitive behavior of melanin synthesis, resulting in a characteristic hair color gradient. In birds, several phenotypes consistent with acromelanism have been reported, but their genetic basis remains unknown. This study aimed to identify the genetic basis of an acromelanistic phenotype in domesticated canaries known as pearl and test whether it is caused by the same molecular mechanism described for mammals. To do this, we compared the genomes of pearl and non-pearl canaries and searched for potentially causative genetic mutations. Our results suggest that the pearl phenotype is caused by a mutation in the TYR gene encoding a TYR-P45H missense substitution. Our findings further suggest that reports of acromelanism in other bird species might be explained by TYR mutations.