Abstract：
Across its Holarctic range, Arctic charr (Salvelinus alpinus) populations have diverged into distinct trophic specialists across independent replicate lakes. The major aspect of divergence between ecomorphs is in head shape and body shape, which are ecomorphological traits reflecting niche use. However, whether the genomic underpinnings of these parallel divergences are consistent across replicates was unknown but key for resolving the substrate of parallel evolution. We investigated the genomic basis of head shape and body shape morphology across four benthivore-planktivore ecomorph pairs of Arctic charr in Scotland. Through genome-wide association analyses, we found genomic regions associated with head shape (89 SNPs) or body shape (180 SNPs) separately and 50 of these SNPs were strongly associated with both body and head shape morphology. For each trait separately, only a small number of SNPs were shared across all ecomorph pairs (3 SNPs for head shape and 10 SNPs for body shape). Signs of selection on the associated genomic regions varied across pairs, consistent with evolutionary demography differing considerably across lakes. Using a comprehensive database of salmonid QTLs newly augmented and mapped to a charr genome, we found several of the head- and body-shape-associated SNPs were within or near morphology QTLs from other salmonid species, reflecting a shared genetic basis for these phenotypes across species. Overall, our results demonstrate how parallel ecotype divergences can have both population-specific and deeply shared genomic underpinnings across replicates, influenced by differences in their environments and demographic histories.
摘要：
在它的北极范围内，北极炭（Salvelinusalpinus）种群已在独立的复制湖泊中分化为不同的营养专家。形态之间分歧的主要方面是头部形状和身体形状，这是反映生态位使用的生态形态特征。然而,这些平行差异的基因组基础是否在重复之间一致是未知的，但对于解决平行进化的底物至关重要。我们研究了苏格兰四对北极炭的头形状和体形形态的基因组基础。通过全基因组关联分析，我们发现基因组区域分别与头形(89个SNP)或体形(180个SNP)相关,其中50个SNP与体形和头形形态密切相关.对于每个特征，在所有生态形态对中只有少量SNP共享(头部形状为3个SNP,身体形状为10个SNP).相关基因组区域上的选择迹象不同，与湖泊之间的进化人口统计差异相当一致。使用新扩增并映射到Charr基因组的鲑鱼QTL的综合数据库，我们发现一些与头部和身体形状相关的SNP在其他鲑鱼物种的形态QTL内或附近，反映了物种间这些表型的共同遗传基础。总的来说,我们的结果证明了平行的生态型差异如何在重复之间具有群体特异性和深度共享的基因组基础，受环境和人口历史差异的影响。
