Molecular Biology Section, Center for the Evolutionary Origins of Human Behavior, Kyoto University, Inuyama, Japan.
Department of Evolutionary Studies of Biosystems, The Graduate University for Advanced Studies, Hayama, Japan.
Sci Rep. 2022 May 9;12(1):7593. doi: 10.1038/s41598-022-11681-z.
Coat color is often highly variable within and between animal taxa. Among hundreds of pigmentation-related genes, melanocortin-1 receptor (MC1R) plays key roles in regulating the synthesis of the dark eumelanin and the red-yellow pheomelanin. The six species of macaques that inhabit Sulawesi Island diverged rapidly from their common ancestor, M. nemestrina. Unlike most macaques, Sulawesi macaques commonly have a dark coat color, with divergence in shade and color pattern. To clarify the genetic and evolutionary basis for coat color in Sulawesi macaques, we investigated the MC1R sequences and functional properties, including basal cAMP production and α-MSH-induced activity in vitro. We found fixed non-synonymous substitutions in MC1R in each species. Furthermore, we found that six species-specific variants corresponded with variation in agonist-induced and basal activity of MC1R. Inconsistent with the dark coat color, four substitutions independently caused decreases in the basal activity of MC1R in M. hecki, M. nigra, M. tonkeana, and M. ochreata. Selective analysis suggested MC1R of M. nigra and M. nigrescens underwent purifying selection. Overall, our results suggest that fixed differences in MC1R resulted in different functional characteristics and might contribute to divergence in color among the six Sulawesi macaque species.
毛色在动物分类单元内和之间通常具有高度变异性。在数百个与色素沉着相关的基因中，黑素皮质素受体 1（MC1R）在调节深色真黑素和红黄色的褐黑素的合成中发挥着关键作用。栖息在苏拉威西岛的六种猕猴迅速从它们的共同祖先猕猴属Nemestrina 分化而来。与大多数猕猴不同，苏拉威西猕猴通常具有深色的被毛颜色，颜色深浅和图案存在差异。为了阐明苏拉威西猕猴毛色的遗传和进化基础，我们研究了 MC1R 序列及其功能特性，包括体外基础 cAMP 产生和 α-MSH 诱导的活性。我们在每个物种中都发现了 MC1R 的固定非同义取代。此外，我们发现六种物种特异性变体与 MC1R 的激动剂诱导和基础活性变化相对应。与深色被毛不一致的是，四个取代独立导致 M.hecki、M.nigra、M.tonkeana 和 M.ochreata 的 MC1R 基础活性降低。选择性分析表明，M. nigra 和 M. nigrescens 的 MC1R 经历了纯化选择。总的来说，我们的结果表明，MC1R 中的固定差异导致了不同的功能特征，并可能导致六种苏拉威西猕猴物种之间的颜色分化。
