Data from: Genes predict long distance migration and large body size in a migratory fish, Pacific lamprey

Elucidation of genetic mechanisms underpinning migratory behavior could help predict how changes in genetic diversity may affect future spatiotemporal distribution of a migratory species. This ability would benefit conservation of one such declining species, anadromous Pacific lamprey (Entosphenus tridentatus). Nonphilopatric migration of adult Pacific lamprey has homogenized population-level neutral variation but has maintained adaptive variation that differentiates groups based on geography, run-timing and adult body form. To investigate causes for this adaptive divergence, we examined 647 adult lamprey sampled at a fixed location on the Columbia River and radiotracked during their subsequent upstream migration. We tested whether genetic variation [94 neutral and adaptive single nucleotide polymorphisms (SNPs) previously identified from a genomewide association study] was associated with phenotypes of migration distance, migration timing, or morphology. Three adaptive markers were strongly associated with morphology, and one marker also correlated with upstream migration distance and timing. Genes physically linked with these markers plausibly influence differences in body size, which is also consistently associated with migration distance in Pacific lamprey. Pacific lamprey conservation implications include the potential to predict an individual's upstream destination based on its genotype. More broadly, the results suggest a genetic basis for intrapopulation variation in migration distance in migratory species.

阐明支撑洄游行为的遗传机制，有助于预测遗传多样性的变化将如何影响洄游物种未来的时空分布格局。这一能力将有益于保护这类正在衰退的物种之一——溯河洄游型太平洋七鳃鳗（Entosphenus tridentatus）。成年太平洋七鳃鳗的非恋巢洄游使种群水平的中性变异趋于均一化，但保留了基于地理分布、洄游时间与成体体型进行群体区分的适应性变异。为探究该适应性分化的成因，我们对在哥伦比亚河固定点位采集的647条成年七鳃鳗展开研究，这些个体在后续的溯河洄游过程中被无线电追踪。我们针对此前通过全基因组关联研究（genome-wide association study）鉴定出的94个中性与适应性单核苷酸多态性（single nucleotide polymorphisms, SNPs）位点，检验其遗传变异是否与洄游距离、洄游时间或体型等表型存在关联。其中3个适应性标记与体型呈现强关联，另有1个标记同时与溯河洄游距离及洄游时间存在相关性。与这些标记存在物理连锁的基因，可合理地影响体型差异——而体型差异在太平洋七鳃鳗中也始终与洄游距离相关联。该研究对太平洋七鳃鳗保护的启示包括：有望通过个体的基因型预测其溯河洄游的目的地。从更广泛的视角来看，研究结果表明洄游物种的种群内洄游距离差异存在遗传基础。