Department of Forest and Wildlife Ecology, University of Wisconsin-Madison, 1630 Linden Drive, Madison, WI 53706, USA.
Mol Ecol. 2012 Jul;21(14):3403-18. doi: 10.1111/j.1365-294X.2012.05635.x. Epub 2012 May 30.
The identification of population bottlenecks is critical in conservation because populations that have experienced significant reductions in abundance are subject to a variety of genetic and demographic processes that can hasten extinction. Genetic bottleneck tests constitute an appealing and popular approach for determining if a population decline has occurred because they only require sampling at a single point in time, yet reflect demographic history over multiple generations. However, a review of the published literature indicates that, as typically applied, microsatellite-based bottleneck tests often do not detect bottlenecks in vertebrate populations known to have experienced declines. This observation was supported by simulations that revealed that bottleneck tests can have limited statistical power to detect bottlenecks largely as a result of limited sample sizes typically used in published studies. Moreover, commonly assumed values for mutation model parameters do not appear to encompass variation in microsatellite evolution observed in vertebrates and, on average, the proportion of multi-step mutations is underestimated by a factor of approximately two. As a result, bottleneck tests can have a higher probability of 'detecting' bottlenecks in stable populations than expected based on the nominal significance level. We provide recommendations that could add rigor to inferences drawn from future bottleneck tests and highlight new directions for the characterization of demographic history.
确定种群瓶颈是保护工作的关键，因为那些数量大幅减少的种群容易受到各种遗传和人口过程的影响，这些过程可能加速灭绝。遗传瓶颈测试是确定种群是否下降的一种有吸引力和流行的方法，因为它们只需要在一个时间点进行采样，但反映了多代的人口历史。然而，对已发表文献的审查表明，如通常应用的那样，基于微卫星的瓶颈测试通常无法检测到已知经历下降的脊椎动物种群中的瓶颈。这一观察结果得到了模拟的支持，模拟结果表明，瓶颈测试检测瓶颈的统计能力有限，主要是由于发表研究中通常使用的样本量有限。此外，通常假设的突变模型参数值似乎没有涵盖脊椎动物中观察到的微卫星进化的变化，而且，平均而言，多步骤突变的比例被低估了约两倍。因此，瓶颈测试在稳定种群中“检测”瓶颈的可能性高于基于名义显著水平的预期。我们提供了一些建议，可以为未来的瓶颈测试推断增加严谨性，并强调了描述人口历史的新方向。
