Facon Benoît, Pointier Jean-Pierre, Jarne Philippe, Sarda Violette, David Patrice
INRA-SPE, Centre de Biologie et de Gestion des Populations, Campus International de Baillarguet, CS 30 016, 34988 Montferrier/Lez cedex, France.
Curr Biol. 2008 Mar 11;18(5):363-7. doi: 10.1016/j.cub.2008.01.063.
Biological invasions represent major threats to biodiversity as well as large-scale evolutionary experiments. Invasive populations have provided some of the best known examples of contemporary evolution [3-6], challenging the classical view that invasive species are genetically depauperate because of founder effects. Yet the origin of trait genetic variance in invasive populations largely remains a mystery, precluding a clear understanding of how evolution proceeds. In particular, despite the emerging molecular evidence that multiple introductions commonly occur in the same place, their contribution to the evolutionary potential of invasives remains unclear. Here, by using a long-term field survey, mtDNA sequences, and a large-scale quantitative genetic experiment on freshwater snails, we document how a spectacular adaptive potential for key ecological traits can be accumulated in invasive populations. We provide the first direct evidence that multiple introductions are primarily responsible for such an accumulation and that sexual reproduction amplifies this effect by generating novel trait combinations. Thus bioinvasions, destructive as they may be, are not synonyms of genetic uniformity and can be hotspots of evolutionary novelty.
生物入侵对生物多样性构成重大威胁，同时也是大规模的进化实验。入侵种群提供了一些当代进化中最著名的例子[3 - 6]，挑战了传统观点，即入侵物种由于奠基者效应而基因匮乏。然而，入侵种群中性状遗传变异的起源在很大程度上仍是个谜，这使得我们无法清楚地了解进化是如何进行的。特别是，尽管新出现的分子证据表明同一地点通常会发生多次引入，但它们对入侵物种进化潜力的贡献仍不明确。在这里，通过长期的野外调查、线粒体DNA序列分析以及对淡水蜗牛进行的大规模数量遗传学实验，我们记录了入侵种群如何能够积累关键生态性状的显著适应潜力。我们提供了首个直接证据，表明多次引入是这种积累的主要原因，并且有性繁殖通过产生新的性状组合放大了这种效应。因此，生物入侵尽管可能具有破坏性，但并非基因一致性的同义词，反而可能是进化新奇性的热点。
