Research/Animal Health, Seattle Aquarium, Seattle, Washington, United States of America.
PLoS One. 2012;7(3):e32205. doi: 10.1371/journal.pone.0032205. Epub 2012 Mar 5.
All existing sea otter, Enhydra lutris, populations have suffered at least one historic population bottleneck stemming from the fur trade extirpations of the eighteenth and nineteenth centuries. We examined genetic variation, gene flow, and population structure at five microsatellite loci in samples from five pre-fur trade populations throughout the sea otter's historical range: California, Oregon, Washington, Alaska, and Russia. We then compared those values to genetic diversity and population structure found within five modern sea otter populations throughout their current range: California, Prince William Sound, Amchitka Island, Southeast Alaska and Washington. We found twice the genetic diversity in the pre-fur trade populations when compared to modern sea otters, a level of diversity that was similar to levels that are found in other mammal populations that have not experienced population bottlenecks. Even with the significant loss in genetic diversity modern sea otters have retained historical structure. There was greater gene flow before extirpation than that found among modern sea otter populations but the difference was not statistically significant. The most dramatic effect of pre fur trade population extirpation was the loss of genetic diversity. For long term conservation of these populations increasing gene flow and the maintenance of remnant genetic diversity should be encouraged.
所有现存的海獭（ Enhydra lutris ）种群都至少经历过一次历史上的种群瓶颈，这是由于 18 世纪和 19 世纪的皮毛贸易灭绝导致的。我们研究了五个微卫星基因座在五个皮毛贸易前海獭种群中的遗传变异、基因流和种群结构：加利福尼亚州、俄勒冈州、华盛顿州、阿拉斯加和俄罗斯。然后，我们将这些值与在当前海獭栖息地的五个现代海獭种群中的遗传多样性和种群结构进行了比较：加利福尼亚州、威廉王子湾、阿穆尔卡岛、东南阿拉斯加和华盛顿州。与现代海獭相比，我们发现皮毛贸易前的种群中有两倍的遗传多样性，这种多样性水平与其他没有经历过种群瓶颈的哺乳动物种群相似。即使现代海獭的遗传多样性显著减少，但它们仍保留了历史结构。在灭绝之前，基因流比现代海獭种群之间的基因流更大，但差异并不显著。皮毛贸易前种群灭绝的最显著影响是遗传多样性的丧失。为了长期保护这些种群，应该鼓励增加基因流和维持剩余的遗传多样性。
