BCO2 - Beta-Carotene Oxigenase 2
This gene encodes an enzyme which oxidizes carotenoids such as beta-carotene during the biosynthesis of vitamin A.
It often takes part in the sexual dimorphism of reptiles and birds, but since that's difference of gene expression, not the carried genetic material, I chose not to include these species.
(I also left out the "yellow fat" alleles, because I focus on the external pigmentation in this series.)
Common wall lizard
yellow
Inheritence: recessive.
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Chicken
yellow shank (possibly two mutations)
Inheritence: recessive
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White-collared manakin, golden-collared manakin
yellow collar
Inheritence: dominant. "The most likely scenario, therefore, is one in which the BCO2 allele for pigmented collars arose once in M. aurantiacus [orange-c.m.], was subsequently transferred through hybridization to vitellinus [golden-c.m.], spread throughout its range, and then partially spread into a third species, M. candei [white-c.m.], in western Panama." (x)
golden-collared, hybrid and white-collared manakin
Canary
red bills and legs
Inheritence: unknown.
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Cocos finch, common cactus finch, Española cactus finch, Genovesa ground finch, large cactus finch, large ground finch, large tree finch, mangrove finch, medium ground finch, medium tree finch, sharp-beaked ground finch, small ground finch, small tree finch, woodpecker finch
juvenile yellow beak (shared allele, mutation occured before species separation)
Inheritence: recessive.
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