Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland.
Semin Cell Dev Biol. 2013 Jun-Jul;24(6-7):594-608. doi: 10.1016/j.semcdb.2013.05.005. Epub 2013 May 9.
Establishing the links between phenotype and genotype is of great importance for resolving key questions about the evolution, maintenance and adaptive function of phenotypic variation. Bird colouration is one of the most studied systems to investigate the role of natural and sexual selection in the evolution of phenotypic diversity. Given the recent advances in molecular tools that allow discovering genetic polymorphisms and measuring gene and protein expression levels, it is timely to review the literature on the genetics of bird colouration. The present study shows that melanin-based colour phenotypes are often associated with mutations at melanogenic genes. Differences in melanin-based colouration are caused by switches of eumelanin to pheomelanin production or by changes in feather keratin structure, melanoblast migration and differentiation, as well as melanosome structure. Similar associations with other types of colourations are difficult to establish, because our knowledge about the molecular genetics of carotenoid-based and structural colouration is quasi inexistent. This discrepancy stems from the fact that only melanin-based colouration shows pronounced heritability estimates, i.e. the resemblance between related individuals is usually mainly explained by genetic factors. In contrast, the expression of carotenoid-based colouration is phenotypically plastic with a high sensitivity to variation in environmental conditions. It therefore appears that melanin-based colour traits are prime systems to understand the genetic basis of phenotypic variation. In this context, birds have a great potential to bring us to new frontiers where many exciting discoveries will be made on the genetics of phenotypic traits, such as colouration. In this context, a major goal of our review is to suggest a number of exciting future avenues.
建立表型和基因型之间的联系对于解决关于表型变异的进化、维持和适应功能的关键问题非常重要。鸟类的颜色是研究自然选择和性选择在表型多样性进化中的作用的最系统之一。鉴于近年来分子工具的进步，这些工具允许发现遗传多态性并测量基因和蛋白质表达水平，因此及时审查关于鸟类颜色的遗传学文献是很有必要的。本研究表明，基于黑色素的颜色表型通常与黑色素生成基因的突变有关。基于黑色素的颜色差异是由真黑素向褐黑素产生的转换或羽毛角蛋白结构、黑素细胞迁移和分化以及黑素体结构的变化引起的。与其他类型的颜色很难建立类似的关联，因为我们对基于类胡萝卜素和结构颜色的分子遗传学的了解几乎不存在。这种差异源于这样一个事实，即只有基于黑色素的颜色表现出明显的遗传力估计，即相关个体之间的相似性通常主要由遗传因素解释。相比之下，基于类胡萝卜素的颜色表达具有表型可塑性，对环境条件的变化高度敏感。因此，似乎基于黑色素的颜色特征是理解表型变异遗传基础的主要系统。在这种情况下，鸟类有很大的潜力将我们带到新的前沿，在那里将在表型特征（如颜色）的遗传学方面做出许多令人兴奋的发现。在这种情况下，我们综述的主要目标之一是提出一些令人兴奋的未来途径。
