Fuller Evolutionary Biology Program, Cornell Lab of Ornithology, Ithaca, NY 14850, USA; Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY 14853, USA.
Department of Biology, Pennsylvania State University, University Park, PA 16802, USA.
Curr Biol. 2022 Oct 24;32(20):R1173-R1186. doi: 10.1016/j.cub.2022.07.076.
Organismal adaptations are the hallmark of natural selection. Studies of adaptations in avian systems have been central to key conceptual and empirical advances in the field of evolutionary biology and, over the past decade, leveraged the proliferation of a diversity of genomic tools. In this synthesis, we first discuss how the different genomic architectures of avian traits are relevant to adaptive phenotypes. A mutation's chromosomal location (e.g., microchromosomes or sex chromosomes) or its specific nature (e.g., nucleotide substitution or structural variant) will determine how it may evolve and shape adaptive phenotypes, and we review different examples from the avian literature. We next describe how the source of adaptive variation, whether from de novo mutations, existing genetic variation, or introgression from another species, can affect the evolutionary dynamics of a trait. Our third section reviews case studies where the genetic basis of key avian adaptive phenotypes (e.g., bill morphology or plumage coloration) have been revealed. We end by providing an outlook and identifying important challenges to this field, both by focusing on technical aspects, such as the completeness of genomic assemblies and the ability to validate genetic associations with new sources of data, as well as by discussing the existential threat posed to birds from habitat alteration and climate change.
生物体的适应是自然选择的标志。鸟类系统适应的研究一直是进化生物学领域关键概念和经验进展的核心，在过去十年中，利用了多种基因组工具的激增。在这篇综述中，我们首先讨论了鸟类特征的不同基因组结构如何与适应性表型相关。一个突变的染色体位置（例如，微染色体或性染色体）或其特定性质（例如，核苷酸取代或结构变异）将决定它可能如何进化并塑造适应性表型，我们从鸟类文献中回顾了不同的例子。接下来，我们描述了适应性变异的来源，无论是来自新的突变、现有的遗传变异还是来自另一个物种的渐渗，如何影响一个特征的进化动态。我们的第三节回顾了关键鸟类适应表型（例如，喙形态或羽毛颜色）的遗传基础的案例研究。最后，我们通过关注技术方面，例如基因组组装的完整性和用新的数据来源验证遗传关联的能力，以及通过讨论栖息地改变和气候变化对鸟类构成的生存威胁，为该领域提供了一个展望并确定了重要的挑战。
