Contrasting population genomic differentiation in two sympatric Triplophysa loaches on the Qinghai-Tibet Plateau

Under global climate change, the Qinghai-Tibet Plateau (QTP) has experienced dramatic environmental changes, including salinity changes of water bodies, which may threaten the biodiversity of aquatic organisms on the ‘roof of the world’. The Tibetan loaches (the genus Triplophysa) are the largest component of the QTP ichthyofauna. Here we compared the population structure and adaptive mechanisms to salinity of two sympatric Tibetan loach species, T. stewarti and T. stenura, using population genomics methods. Using both the ‘common’ and ‘individual’ SNP datasets of seven populations from five localities of the two species, we found out that the two species showed entirely different patterns of population differentiation, with T. stewarti populations deeply diverged and T. stenura populations mixed. We identified a catalogue of candidate genes possibly involved in salinity acclimatation of the two species using both unsupervised and supervised population differentiation methods. In this s...在全球气候变化背景下，青藏高原（Qinghai-Tibet Plateau, QTP）正经历剧烈的环境变化，其中包括水体盐度改变，这可能威胁到这座“世界屋脊”水生生物的生物多样性。高原鳅属（Triplophysa）鱼类是青藏高原鱼类区系的最大组成类群。本研究利用群体基因组学方法，对比了两种同域分布的高原鳅物种——斯氏高原鳅（T. stewarti）与细尾高原鳅（T. stenura）的种群结构及其对盐度的适应机制。本研究使用采自5个采样点的7个种群的"通用"与"个体"单核苷酸多态性（Single Nucleotide Polymorphism, SNP）数据集，发现两种高原鳅的种群分化模式完全迥异：斯氏高原鳅种群分化程度极深，而细尾高原鳅种群存在混合现象。本研究通过无监督与有监督的种群分化分析方法，筛选出了可能与两种高原鳅盐度适应相关的候选基因集。在本研究的s...