In other species: chicken , black swan , Coscoroba swan , Bananaquit , helmeted guineafowl , gyrfalcon , Lesser snow goose , Arctic skua , , brown booby , zebra finch , ruff , rock pigeon , Eleonora's falcon , pomarine skua , king penguin

Possibly relevant human trait(s) and/or gene(s)s (MIM numbers): 266300 (trait) , 155555 (gene)

Mendelian trait/disorder: yes

Mode of inheritance: Autosomal

Considered a defect: no

Key variant known: yes

Year key variant first reported: 2007

Species-specific description: Baião et al. (2007): "The red-footed booby (Sula sula) is considered one of the most polymorphic seabirds, with 3 recognized major adult plumage types: 1) white, 2) white-tailed brown, and 3) brown and several degrees of intermediates."

Molecular basis: Baião et al. (2007): "the white/melanic polymorphism observed in this species is perfectly associated with 2 point substitutions, Val85Met and His207Arg, at the melanocortin-1 receptor (MC1R) gene. . . . All the white morph red-footed boobies sampled (N = 47) were homozygous for the Val85 and the His207 alleles, whereas all the melanic birds (brown, white-tailed brown, and intermediates) sampled (N = 84) were homozygous or heterozygous for the Met85 and Arg207 alleles. . . . Furthermore, the Val85Met point substitution has been previously shown to be associated with melanic phenotypes in the lesser snow goose (Anser c. caerulescens), suggesting parallel evolution of the melanic allele, and hence, melanism, between these 2 distantly related species. We also compared the MC1R locus in red-footed boobies with a nonpolymorphic congener, the Nazca booby (Sula granti), in which all adults are white. We found that Nazca boobies present the same genotype at sites 85 and 207 [namely 85Val and 207His] as white morph red-footed boobies."

Associated gene: