Population bottlenecks can reduce genetic diversity and may lead to inbreeding depression. However, some studies have provided evidence that long lifespans buffer negative genetic effects of bottlenecks. Others have cautioned that longevity might merely mask the effects of genetic drift, which will still affect long-term population viability. We used microsatellite data from actual populations of tuatara (Sphenodon punctatus) and eastern massasaugas (Sistrurus catenatus) as a starting point for simulated population declines to evaluate the performance of bottleneck tests under a range of scenarios. We quantified losses in genetic diversity for each scenario and assessed the power of commonly used tests (i.e., M-ratio, heterozygosity excess, and mode-shift) to detect known bottlenecks in these moderate- to long-lived species. Declines in genetic diversity were greater in bottlenecks simulated for eastern massasaugas, the shorter-lived species, and mode-shift and heterozygosity excess tests were more sensitive to population declines in this species. Conversely, M-ratio tests were more sensitive to bottlenecks simulated in tuatara. Despite dramatic simulated population declines, heterozygosity excess and mode-shift tests often failed to detect bottlenecks in both species, even when large losses in genetic diversity had occurred (both allelic diversity and heterozygosity). While not eliminating type II error, M-ratio tests generally performed best and were most reliable when a critical value (Mc) of 0.68 was used. However, in tuatara simulations, M-ratio tests had high rates of type I error when Mc was calculated assuming θ = 10. Our results suggest that reliance on these tests could lead to misguided species management decisions.

中文翻译：

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尽管失去了遗传多样性，但长寿物种的低瓶颈检测：Tuatara 和东部马萨索加响尾蛇的案例研究

种群瓶颈会降低遗传多样性，并可能导致近亲繁殖衰退。然而，一些研究提供的证据表明，长寿命可以缓冲瓶颈的负面遗传影响。其他人警告说，长寿可能只是掩盖了遗传漂变的影响，这仍会影响长期的种群生存能力。我们使用来自 tuatara (Sphenodon punctatus) 和东部 massasaugas (Sistrurus catenatus) 实际种群的微卫星数据作为模拟种群下降的起点，以评估一系列场景下瓶颈测试的性能。我们量化了每种情况下遗传多样性的损失，并评估了常用测试（即 M 比、杂合性过剩和模式转换）的能力，以检测这些中长寿物种中的已知瓶颈。在模拟东部massaugas（寿命较短的物种）的瓶颈中遗传多样性的下降幅度更大，并且模式转变和杂合性过度测试对该物种的种群下降更为敏感。相反，M 比测试对 tuatara 中模拟的瓶颈更敏感。尽管模拟的种群数量急剧下降，但杂合性过剩和模式转换测试通常无法检测到这两个物种的瓶颈，即使发生了遗传多样性的大量损失（等位基因多样性和杂合性）。虽然不能消除 II 类错误，但当使用 0.68 的临界值 (Mc) 时，M 比测试通常表现最好并且最可靠。然而，在 tuatara 模拟中，当假设 θ = 10 计算 Mc 时，M 比率测试的 I 型错误率很高。