Genetic rescue of an insular population of large mammals
Genetic rescue of an insular population of large mammals
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DOI：
10.1098/rspb.2006.3477
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发表时间：
2006-06-22
影响因子：
4.7
通讯作者：
Luikart, Gordon
中科院分区：
文献类型：
--
作者：
Hogg, John T.;Forbes, Stephen H.;Luikart, Gordon
世界各地的自然种群因栖息地丧失而日益支离破碎。人们认为，小种群规模的隔离会通过近亲繁殖抑制来降低个体和种群的适应性。然而，人们对自然种群中可能产生不利遗传效应的时间范围或可能受到影响的性状的数量和类型知之甚少。因此，恢复分离株的基因流的好处在很大程度上也是未知的。相比之下，移民的潜在成本（例如疾病传播）是显而易见的。因此，生态连通性管理一直存在争议，有时甚至被回避。我们利用 25 年研究期间收集的谱系和生活史数据，评估了 1922 年由 12 个人建立的大角羊种群的遗传衰退和拯救，该种群平均大小为 42 只，历经 10-12 代。从 1985 年开始，移民实验性地恢复了。我们发现 15 名新移民的后代在繁殖、生存和五项健康相关特征方面都有显着改善。最大远交个体的性状值增加了 23-257%。据我们所知，这是首次证明在完全竞争的自然环境中通过近亲繁殖来提高雄性和雌性的适应性。我们的研究结果表明，遗传原理作为实用的管理工具值得得到更广泛的认可，对大型哺乳动物的保护具有近期影响。
Natural populations worldwide are increasingly fragmented by habitat loss. Isolation at small population size is thought to reduce individual and population fitness via inbreeding depression. However, little is known about the time-scale over which adverse genetic effects may develop in natural populations or the number and types of traits likely to be affected. The benefits of restoring gene flow to isolates are therefore also largely unknown. In contrast, the potential costs of migration (e.g. disease spread) are readily apparent. Management for ecological connectivity has therefore been controversial and sometimes avoided. Using pedigree and life-history data collected during 25 years of study, we evaluated genetic decline and rescue in a population of bighorn sheep founded by 12 individuals in 1922 and isolated at an average size of 42 animals for 10-12 generations. Immigration was restored experimentally, beginning in 1985. We detected marked improvements in reproduction, survival and five fitness-related traits among descendants of the 15 recent migrants. Trait values were increased by 23-257% in maximally outbred individuals. This is the first demonstration, to our knowledge, of increased male and female fitness attributable to outbreeding realized in a fully competitive natural setting. Our findings suggest that genetic principles deserve broader recognition as practical management tools with near-term consequences for large-mammal conservation.