Genomic footprints of adaptation in a cooperatively breeding tropical bird across a vegetation gradient

Identifying the genetic basis of phenotypic variation and its relationship with the environment is key to understanding how local adaptations evolve. Such patterns are especially interesting among populations distributed across habitat gradients, where genetic structure can be driven by isolation by distance (IBD) and/or isolation by environment (IBE). Here, we used variation in ~1,600 high-quality SNPs derived from paired-end sequencing of double-digest restriction site-associated DNA (ddRAD-Seq) to test hypotheses related to IBD and IBE in the Yucatan jay (Cyanocorax yucatanicus), a tropical bird endemic to the Yucatán Peninsula. This peninsula is characterized by a precipitation and vegetation gradient—from dry to evergreen tropical forests—that is associated with morphological variation in this species. We found a moderate level of nucleotide diversity (π = .008) and little evidence for genetic differentiation among vegetation types. Analyses of neutral and putatively adaptive SNPs ...

阐明表型变异的遗传基础及其与环境的关联，是解析局部适应演化机制的核心要务。这类演化格局在沿生境梯度分布的种群中尤为值得关注——此类种群的遗传结构可由距离隔离（isolation by distance, IBD）和/或环境隔离（isolation by environment, IBE）驱动。本研究依托双酶切限制性位点相关DNA测序（double-digest restriction site-associated DNA sequencing, ddRAD-Seq）的双端测序数据，获取了约1600个高质量单核苷酸多态性（single nucleotide polymorphism, SNP）位点变异，并以此对尤卡坦鸦鹃（Cyanocorax yucatanicus）的距离隔离与环境隔离相关假说展开验证。尤卡坦鸦鹃是仅分布于尤卡坦半岛的特有热带鸟类，该半岛存在降水与植被的梯度变化——从干旱林到常绿热带林——且该梯度与该物种的形态变异存在关联。本研究检测到中等水平的核苷酸多样性（π = 0.008），且未发现不同植被类型间存在显著遗传分化。针对中性及推定适应性单核苷酸多态性的分析……