Guernsey Michael W, Ritscher Lars, Miller Matthew A, Smith Daniel A, Schöneberg Torsten, Shapiro Michael D
Department of Biology, University of Utah, Salt Lake City, Utah, United States of America.
PLoS One. 2013 Aug 15;8(8):e74475. doi: 10.1371/journal.pone.0074475. eCollection 2013.
Variation in the melanocortin-1 receptor (Mc1r) is associated with pigmentation diversity in wild and domesticated populations of vertebrates, including several species of birds. Among domestic bird species, pigmentation variation in the rock pigeon (Columbalivia) is particularly diverse. To determine the potential contribution of Mc1r variants to pigment diversity in pigeons, we sequenced Mc1r in a wide range of pigeon breeds and identified several single nucleotide polymorphisms, including a variant that codes for an amino acid substitution (Val85Met). In contrast to the association between Val85Met and eumelanism in other avian species, this change was associated with pheomelanism in pigeons. In vitro cAMP accumulation and protein expression assays revealed that Val85Met leads to decreased receptor function and reduced cell surface expression of the mutant protein. The reduced in vitro function is consistent with the observed association with reduced eumelanic pigmentation. Comparative genetic and cellular studies provide important insights about the range of mechanisms underlying diversity among vertebrates, including different phenotypic associations with similar mutations in different species.
黑皮质素-1受体（Mc1r）的变异与脊椎动物野生和驯化种群（包括几种鸟类）的色素沉着多样性有关。在家禽物种中，岩鸽（Columbalivia）的色素沉着变异尤为多样。为了确定Mc1r变体对鸽子色素多样性的潜在贡献，我们对多种鸽子品种的Mc1r进行了测序，并鉴定出了几个单核苷酸多态性，包括一个编码氨基酸替换（Val85Met）的变体。与Val85Met和其他鸟类物种的真黑素沉着之间的关联不同，这种变化与鸽子的褐黑素沉着有关。体外cAMP积累和蛋白质表达分析表明，Val85Met导致受体功能下降和突变蛋白的细胞表面表达减少。体外功能的降低与观察到的与真黑素沉着减少的关联一致。比较遗传学和细胞研究为脊椎动物多样性背后的机制范围提供了重要见解，包括不同物种中相似突变的不同表型关联。
