Spontaneous hybridization and introgression between walleye (Sander vitreus) and sauger (S. canadensis) in two large reservoirs: insights from genotyping-by-sequencing

Anthropogenic activities may facilitate undesirable hybridization and genomic introgression between fish species. Walleye (Sander vitreus) and sauger (Sander canadensis) are economically valuable freshwater species that can spontaneously hybridize in areas of sympatry. Levels of genomic introgression between walleye and sauger may be increased by modifications to waterbodies (e.g., reservoir development) and inadvertent propagation of hybrids in stocking programs. We used genotyping by sequencing (GBS) to examine 217 fish from two large reservoirs with mixed populations of walleye and sauger in Saskatchewan, Canada (Lake Diefenbaker, Tobin Lake). Analyses with 20,038 (r90) and 478 (r100) SNPs clearly resolved walleye and sauger, and classified hybrids with high confidence. F1, F2, and multi-generation hybrids were detected in Lake Diefenbaker, indicating potentially high levels of genomic introgression. In contrast, only F1 hybrids were detected in Tobin Lake. Field classification of fi...

人类活动可能会促进鱼类物种间发生不良杂交与基因组渐渗（genomic introgression）。白斑梭鲈（Walleye, Sander vitreus）与萨氏梭鲈（Sauger, Sander canadensis）均为具有经济价值的淡水鱼类，二者在同域分布区域可发生自然杂交。水体改造（如水库修建）以及放养计划中无意间增殖或引入杂交个体，可能会提升二者间的基因组渐渗水平。本研究采用测序分型（genotyping by sequencing, GBS）技术，对加拿大萨斯喀彻温省两处存在白斑梭鲈与萨氏梭鲈混合种群的大型水库——迪芬贝克湖与托宾湖——中的217尾鱼类样本展开检测。通过20038个（r90）与478个（r100）单核苷酸多态性（Single Nucleotide Polymorphism, SNP）标记开展的分析，可清晰区分白斑梭鲈与萨氏梭鲈，并以高置信度完成杂交个体的分类。迪芬贝克湖中检测到F1、F2及多代杂交个体，表明该区域基因组渐渗水平可能较高；与之相反，托宾湖中仅检测到F1代杂交个体。鱼类的野外分类……