Campbell Nathan R, Kamphaus Cory, Murdoch Keely, Narum Shawn R
Columbia River Inter-Tribal Fish Commission Hagerman ID USA.
Yakama Nation Fisheries Yakima WA USA.
Ecol Evol. 2017 Oct 30;7(23):10350-10360. doi: 10.1002/ece3.3492. eCollection 2017 Dec.
Coho salmon were extirpated in the mid-20th century from the interior reaches of the Columbia River but were reintroduced with relatively abundant source stocks from the lower Columbia River near the Pacific coast. Reintroduction of Coho salmon to the interior Columbia River (Wenatchee River) using lower river stocks placed selective pressures on the new colonizers due to substantial differences with their original habitat such as migration distance and navigation of six additional hydropower dams. We used restriction site-associated DNA sequencing (RAD-seq) to genotype 5,392 SNPs in reintroduced Coho salmon in the Wenatchee River over four generations to test for signals of temporal structure and adaptive variation. Temporal genetic structure among the three broodlines of reintroduced fish was evident among the initial return years (2000, 2001, and 2002) and their descendants, which indicated levels of reproductive isolation among broodlines. Signals of adaptive variation were detected from multiple outlier tests and identified candidate genes for further study. This study illustrated that genetic variation and structure of reintroduced populations are likely to reflect source stocks for multiple generations but may shift over time once established in nature.
银大麻哈鱼在20世纪中叶从哥伦比亚河的内陆河段灭绝，但后来从太平洋沿岸附近的哥伦比亚河下游引入了数量相对丰富的原种。利用下游种群将银大麻哈鱼重新引入哥伦比亚河内陆（韦纳奇河），这给新的定居者带来了选择压力，因为新栖息地与它们原来的栖息地有很大差异，比如洄游距离以及还要经过另外六座水电大坝。我们使用限制性位点关联DNA测序（RAD-seq）技术，对重新引入韦纳奇河的银大麻哈鱼四代中的5392个单核苷酸多态性（SNP）进行基因分型，以检测时间结构信号和适应性变异。重新引入的鱼类的三个繁殖系之间的时间遗传结构在最初的洄游年份（2000年、2001年和2002年）及其后代中很明显，这表明繁殖系之间存在生殖隔离水平。通过多次异常值检验检测到适应性变异信号，并确定了供进一步研究的候选基因。这项研究表明，重新引入种群的遗传变异和结构可能在多代中反映原种，但一旦在自然环境中建立，可能会随时间发生变化。
