Weber D S, Stewart B S, Lehman N
Department of Biological Sciences, University at Albany, State University of New York, Albany, NY 12222, USA.
J Hered. 2004 Mar-Apr;95(2):144-53. doi: 10.1093/jhered/esh018.
Population bottlenecks may lead to diminished genetic variability and correlative effects on fitness. The Guadalupe fur seal was nearly exterminated by commercial sealers during the late 18th and early 19th centuries. To determine the genetic consequences of this population bottleneck, we compared the variation at a 181 bp section of the mitochondrial DNA (mtDNA) control region from the bones of 26 prebottleneck fur seals versus variation in the extant population. We found 25 different mtDNA genotypes in the prebottleneck fur seals and only 7 genotypes among 32 extant fur seals, including only one of the ancient genotypes. These data demonstrate a substantial loss of genetic variability correlating with the recent population bottleneck. We also found from several genetic measures that the prehistoric population of Guadalupe fur seals was robust and that it had been increasing at some time during the late prehistoric period. Continued recovery of this species may, however, owe more to more immediate nongenetic factors, such as poaching and local availability of food resources during the breeding season and consequent effects on pup survival, than on the reduced genetic variability.
种群瓶颈可能导致遗传变异性降低以及对适应性的相关影响。瓜达卢佩海狗在18世纪末和19世纪初几乎被商业捕猎者灭绝。为了确定这一种群瓶颈的遗传后果，我们比较了26只瓶颈前海狗骨骼中线粒体DNA（mtDNA）控制区181bp片段的变异与现存种群的变异。我们在瓶颈前海狗中发现了25种不同的mtDNA基因型，而在32只现存海狗中仅发现7种基因型，其中只有一种是古代基因型。这些数据表明，遗传变异性大幅丧失与近期的种群瓶颈相关。我们还从多项遗传指标中发现，瓜达卢佩海狗的史前种群数量庞大，且在史前晚期的某个时期一直在增长。然而，该物种的持续恢复可能更多地归因于更直接的非遗传因素，例如繁殖季节的偷猎和当地食物资源的可获得性以及对幼崽生存的后续影响，而非遗传变异性的降低。
