Kaeuffer Renaud, Coltman David W, Chapuis Jean-Louis, Pontier Dominique, Réale Denis
Canada Research Chair in behavioural ecology and GRECA, Département des Sciences Biologiques, Université du Québec à Montréal, CP 8888 succursale centre-ville, Montréal, Quebec H3C 3P8, Canada.
Proc Biol Sci. 2007 Feb 22;274(1609):527-33. doi: 10.1098/rspb.2006.3743.
In population and conservation genetics, there is an overwhelming body of evidence that genetic diversity is lost over time in small populations. This idea has been supported by comparative studies showing that small populations have lower diversity than large populations. However, longitudinal studies reporting a decline in genetic diversity throughout the whole history of a given wild population are much less common. Here, we analysed changes in heterozygosity over time in an insular mouflon (Ovis aries) population founded by two individuals in 1957 and located on one of the most isolated locations in the world: the Kerguelen Sub-Antarctic archipelago. Heterozygosity measured using 25 microsatellite markers has actually increased over 46 years since the introduction, and exceeds the range predicted by neutral genetic models and stochastic simulations. Given the complete isolation of the population and the short period of time since the introduction, changes in genetic variation cannot be attributed to mutation or migration. Several lines of evidence suggest that the increase in heterozygosity with time may be attributable to selection. This study shows the importance of longitudinal genetic surveys for understanding the mechanisms that regulate genetic diversity in wild populations.
在种群遗传学和保护遗传学领域，有大量证据表明，小种群的遗传多样性会随着时间推移而丧失。比较研究支持了这一观点，这些研究表明小种群的多样性低于大种群。然而，报告某一特定野生种群在其整个历史过程中遗传多样性下降的纵向研究则要少见得多。在此，我们分析了一个岛屿摩弗伦羊（盘羊）种群杂合度随时间的变化情况。该种群于1957年由两只个体建立，位于世界上最孤立的地点之一：凯尔盖朗亚南极群岛。自引入以来的46年里，使用25个微卫星标记测量的杂合度实际上有所增加，并且超出了中性遗传模型和随机模拟预测的范围。鉴于该种群完全隔离且引入后时间较短，遗传变异的变化不能归因于突变或迁移。多条证据表明，杂合度随时间的增加可能归因于选择。这项研究表明了纵向遗传调查对于理解调控野生种群遗传多样性机制的重要性。
