Yang J, Liu X, Zhang J, Qing B, Lu B
Northwest A&F University College of Animal Science and Technology Yangling China.
Crested ibis National Nature Reserve Administration of Shaanxi Hanzhong Yangxian China.
Cell Mol Biol (Noisy-le-grand). 2015 Aug 28;61(4):63-9.
The melanocortin-1-recepter gene (MC1R), an important regulator in melanin synthesis, may cause different plumage color patterns in birds: gain-of-function mutations lead to the synthesis of eumelanin, whereas loss-of-function mutations help to generate pheomelanin synthesis. We had chosen MC1R as a candidate gene for the depigmentation of crested ibis, cloned and sequenced the crested ibis MC1R gene the first time. The crested ibis MC1R sequence, highly conserved with other birds during evolution, had seven transmembrane domains which played an indispensable function through evolution. We did not found any substitution on this sequence among all the sample individuals. The phylogenetic tree showed that crested ibis separated early in the evolution of birds. TYR, TYRP1, TYRP2 and MC1R were expressed in blood and the expression of the four genes showed no significant difference (p>0.05) between normal and albinism individuals, and this result demonstrated that melanic pigments are not involved in the production of red pigmentation in birds. Further study of the crested ibis albinism should focus on analyzing carotenoid-based genes.
黑皮质素-1-受体基因（MC1R）是黑色素合成中的一个重要调节因子，可能导致鸟类出现不同的羽毛颜色模式：功能获得性突变会导致真黑色素的合成，而功能丧失性突变则有助于产生褐黑色素的合成。我们选择MC1R作为朱鹮色素脱失的候选基因，首次克隆并测序了朱鹮的MC1R基因。朱鹮的MC1R序列在进化过程中与其他鸟类高度保守，有七个跨膜结构域，这些结构域在进化过程中发挥着不可或缺的作用。在所有样本个体中，我们在该序列上未发现任何替换。系统发育树表明，朱鹮在鸟类进化过程中很早就分支出来了。TYR、TYRP1、TYRP2和MC1R在血液中表达，正常个体和白化个体之间这四个基因的表达没有显著差异（p>0.05），这一结果表明黑色素色素不参与鸟类红色素沉着的产生。对朱鹮白化病的进一步研究应集中在分析基于类胡萝卜素的基因上。
