Data from: Genetic and phenotypic divergence between low- and high-altitude populations of two recently diverged cinnamon teal subspecies

Spatial variation in the environment can lead to divergent selection between populations occupying different parts of a species’ range, and ultimately lead to population divergence. The colonization of new areas can thus facilitate divergence in beneficial traits, yet with little differentiation at neutral genetic markers. We investigated genetic and phenotypic patterns of divergence between low- and high-altitude populations of cinnamon teal inhabiting normoxic and hypoxic regions in the Andes and adjacent lowlands of South America. Cinnamon Teal showed strong divergence in body size (PC1; PST = 0.56) and exhibited significant frequency differences in a single non-synonymous α-hemoglobin amino acid polymorphism (Asn/Ser-α9; FST = 0.60) between environmental extremes, despite considerable admixture of mtDNA and intron loci (FST = 0.004–0.168). Inferences of strong population segregation were further supported by the observation of few mismatched individuals in either environmental extreme. Coalescent analyses indicated that the highlands were most likely colonized from lowland regions but following divergence, gene flow has been asymmetric from the highlands into the lowlands. Multiple selection pressures associated with high altitude habitats, including cold and hypoxia, have likely shaped morphological and genetic divergence within South American cinnamon teal populations.环境空间异质性可导致物种分布范围内不同生境的种群间产生歧化选择，最终引发种群分化。新区域的定殖可促进有益性状的歧化，但中性遗传标记（neutral genetic markers）的分化程度却极低。本研究针对栖息于南美洲安第斯山脉及邻近低地的常氧（normoxic）与低氧（hypoxic）生境中的肉桂鸭（Cinnamon Teal）低海拔与高海拔种群，探究了二者的遗传与表型分化模式。尽管线粒体DNA（mtDNA, mitochondrial DNA）与内含子位点存在显著的基因混合（FST值为0.004~0.168），但肉桂鸭在体型（主成分1，PC1；PST=0.56）上呈现出强烈的分化，且在极端环境间的单个非同义α-血红蛋白氨基酸多态位点（Asn/Ser-α9；FST=0.60）上存在显著的频率差异。在两类极端生境中几乎未发现遗传背景混杂的个体，这进一步佐证了种群间存在强烈分化的结论。溯祖分析（Coalescent analysis）结果显示，高海拔种群大概率起源于低海拔种群的定殖，但在种群分化后，基因流呈现出从高海拔向低海拔的不对称性。与高海拔生境相关的多重选择压力（包括低温与低氧），很可能塑造了南美洲肉桂鸭种群的形态与遗传分化。