The genetic basis of melanism in the gray squirrel (Sciurus carolinensis)

McRobie, Helen R., Thomas, Alison P. M. and Kelly, Jo (2009) The genetic basis of melanism in the gray squirrel (Sciurus carolinensis). Journal of Heredity, 100 (6). pp. 709-714. ISSN 1465-7333

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The black squirrel is a melanic variant of the gray squirrel (Sciurus carolinensis). We found 3 coat color variants in the gray squirrel: the wild-type gray, a jet-black, and a brown–black phenotype. These 3 morphs are due to varying distributions of eumelanin and phaeomelanin pigment in hairs. The melanocortin 1 receptor (MC1R) plays a central role in regulating eumelanin and phaeomelanin production. We sequenced the MC1R gene for all 3 coat color phenotypes and found a 24 base-pair deletion. The gray phenotype was homozygous for the wild-type allele E+, the jet-black phenotype was homozygous for the MC1R-Δ24 allele EB, and the brown–black phenotype was heterozygous for the E+ and EB alleles. We conclude that melanism in gray squirrels is associated with the MC1R-Δ24 EB allele at amino acid positions 87–94 and that this allele is incompletely dominant to the wild-type allele. We predict that the MC1R-Δ24 EB allele encodes a constitutively active or hyperactive receptor.

Item Type: Journal Article
Keywords: gray squirrel, MC1R, melanocortin 1 receptor, melanism, Sciurus carolinensis
Faculty: ARCHIVED Faculty of Science & Technology (until September 2018)
Depositing User: Repository Admin
Date Deposited: 16 Sep 2013 15:33
Last Modified: 09 Sep 2021 16:18

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