Moore Jim
Anthropology Department 0532, University of California, San Diego, La Jolla, CA 92093, USA.
Mol Ecol. 2007 Nov;16(21):4421-3. doi: 10.1111/j.1365-294X.2007.03560.x.
Perhaps the most important 'decision' made by any animal (or plant) is whether to disperse--leave kith and kin, or remain with the familiar and related. The benefits of staying at home are obvious, so dispersal requires an explanation--and the most popular is that dispersal functions to avoid inbreeding depression. Strong support comes from the observation that dispersal is so often sex biased. Simply put, all else being equal members of both sexes should prefer to remain philopatric, but this would lead to inbreeding depression so members of one sex have to disperse. In principle, this link between inbreeding depression and sex-biased dispersal could be broken if individuals recognize close kin and avoid mating with them. Archie et al. (2007) provide one of the most compelling analyses to date of the interaction among inbreeding avoidance, kin recognition and mating strategies in any mammal, clearly showing that elephants recognize even close paternal kin and avoid mating with them. Their important results illuminate the subtleties of elephant inbreeding avoidance as well as illustrate the difficulty of arriving at definitive answers to questions about the evolution of dispersal behaviour.
或许任何动物（或植物）做出的最重要的“决定”就是是否要扩散——离开亲朋好友，还是与熟悉的和有亲缘关系的个体待在一起。待在家里的好处显而易见，所以扩散行为需要一个解释——而最普遍的解释是扩散的作用是避免近亲繁殖衰退。有力的支持来自这样一个观察结果，即扩散行为往往存在性别偏差。简单来说，在其他条件相同的情况下，两性的个体都应该更倾向于留居原地，但这会导致近亲繁殖衰退，所以其中一性别的个体不得不扩散。原则上，如果个体能够识别近亲并避免与其交配，那么近亲繁殖衰退和性别偏差扩散之间的这种联系就可能被打破。阿奇等人（2007年）提供了迄今为止对任何哺乳动物近亲繁殖避免、亲缘识别和交配策略之间相互作用最有说服力的分析之一，清楚地表明大象甚至能识别父系近亲并避免与其交配。他们的重要研究结果揭示了大象近亲繁殖避免行为的微妙之处，也说明了要确定关于扩散行为进化问题的明确答案是多么困难。
