Molecular mechanism of sexual dimorphism and age-dependent changes in feather coloration

雄鸟的羽色鲜艳，因此在许多鸟类中都可以看到有性羽的二色性;然而，这背后的分子机制仍然不清楚。在冈山鸡中，小鸡和成年雌性的羽毛都是用暗色的羽毛来抵消阴影。相比之下，成年雄性的背部有鲜艳的装饰性羽毛。利用该品种，我们研究了鸟类性羽二色性的分子机制，我们的研究结果表明，当地的黑皮质素系统调节羽毛的色素沉着和个别羽毛的精细的颜色模式是由ASIP的拮抗作用的一部分。此外，远端ASIP启动子不仅在小鸡和成年雌性中产生反遮蔽，而且在创造性羽毛二色性中起重要作用。ASIP基因可能在进化过程中改变了其表达，以发展不同性别个体之间的表型多样性。

Brilliant plumage is typical of male birds, thus sexual plumage dichromatism is seen in many avian species; however, the molecular mechanism underlying this remains unclear. In Okayama-Jidori chickens, chick and adult female plumages are countershading with dull-colored feathers. In contrast, adult males are colorful with bright ornamental feathers on the back. Using this breed, we investigated molecular mechanism underlying the sexual plumage dichromatism in birds.Our findings suggest that the local melanocortin system regulates feather pigmentation and the elaborate color pattern of individual feathers is formed in part by the antagonistic action of ASIP. Furthermore, the distal ASIP promoter not only acts to produce countershading in chicks and adult females, but also plays an important role for creating sexual plumage dichromatism. The ASIP gene may have been modified in its expression during evolution to develop phenotypic diversity between individuals of different sexes.