Data from: Evolutionary history of a dispersal-associated locus across sympatric and allopatric divergent populations of a wing-polymorphic beetle across Atlantic Europe

Studying the evolutionary history of trait divergence, in particular those related to dispersal capacity, is of major interest for the process of local adaptation and metapopulation dynamics. Here, we reconstruct the evolution of different alleles at the nuclear encoded mitochondrial NADP+-dependent isocitrate dehydrogenase (mtIdh) locus of the ground beetle Pogonus chalceus that are differentially and repeatedly selected in short- and long-winged populations in response to different hydrological regimes at both allopatric and sympatric scales along the Atlantic European coasts. We sequenced 2,788 bp of the mtIdh locus spanning a ~7 kb genome region and compared its variation with that of two supposedly neutral genes. mtIdh sequences show (i) monophyletic clustering of the short-winged associated mtIDH-DE haplotypes within the long-winged associated mtIDH-AB haplotypes, (ii) a more than tenfold lower haplotype diversity associated with the mtIDH-DE alleles compared to the mtIDH-AB alleles, and (iii) a high number of fixed nucleotide differences between both mtIDH haplotype clusters. Coalescent simulations suggest that this observed sequence variation in the mtIdh locus is most consistent with a singular origin in a partially isolated subpopulation, followed by a relatively recent spread of the mtIDH-DE allele in short-winged populations along the Atlantic coast. These results demonstrate that even traits associated with decreased dispersal capacity can rapidly spread and that reuse of adaptive alleles plays an important role in the adaptive potential within this sympatric mosaic of P. chalceus populations.

研究性状分化（尤其是与扩散能力相关的性状分化）的演化历史，对于局部适应与集合种群动态过程具有重要的研究价值。本研究以欧洲大西洋沿岸异域与同域分布尺度下、受不同水文条件驱动，在短翅和长翅种群中受到差异化且反复选择的步甲（Pogonus chalceus）为研究对象，解析其核编码线粒体烟酰胺腺嘌呤二核苷酸磷酸（NADP+）依赖性异柠檬酸脱氢酶（mtIdh）位点的不同等位基因的演化历程。我们对跨越约7kb基因组区域的2788 bp mtIdh位点序列进行了测序，并将其序列变异与两个假定的中性基因进行了比对分析。mtIdh序列分析结果显示：（1）与短翅型相关的mtIDH-DE单倍型在与长翅型相关的mtIDH-AB单倍型簇内形成单系聚类；（2）mtIDH-DE等位基因的单倍型多样性较mtIDH-AB等位基因低十倍以上；（3）两类mtIDH单倍型簇之间存在大量固定核苷酸差异。溯祖模拟（Coalescent simulations）结果显示，mtIdh位点观测到的序列变异，最符合以下演化场景：在部分隔离的亚种群中单次起源，随后mtIDH-DE等位基因在大西洋沿岸的短翅种群中发生了相对近期的扩散。本研究结果表明，即便与扩散能力降低相关的性状，也能够快速扩散；且在P. chalceus种群的同域镶嵌分布格局中，适应性等位基因的重复利用在种群的适应性潜力中发挥着重要作用。