Northwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Seattle, WA 98112, USA.
Proc Biol Sci. 2013 Aug 7;280(1768):20131339. doi: 10.1098/rspb.2013.1339. Print 2013 Oct 7.
Effective population size (Ne) controls both the rate of random genetic drift and the effectiveness of selection and migration, but it is difficult to estimate in nature. In particular, for species with overlapping generations, it is easier to estimate the effective number of breeders in one reproductive cycle (Nb) than Ne per generation. We empirically evaluated the relationship between life history and ratios of Ne, Nb and adult census size (N) using a recently developed model (agene) and published vital rates for 63 iteroparous animals and plants. Nb/Ne varied a surprising sixfold across species and, contrary to expectations, Nb was larger than Ne in over half the species. Up to two-thirds of the variance in Nb/Ne and up to half the variance in Ne/N was explained by just two life-history traits (age at maturity and adult lifespan) that have long interested both ecologists and evolutionary biologists. These results provide novel insights into, and demonstrate a close general linkage between, demographic and evolutionary processes across diverse taxa. For the first time, our results also make it possible to interpret rapidly accumulating estimates of Nb in the context of the rich body of evolutionary theory based on Ne per generation.
有效种群大小 (Ne) 控制着随机遗传漂变的速度和选择与迁移的效率，但在自然界中很难估计。特别是对于具有重叠世代的物种，在一个繁殖周期中估计有效繁殖者数量 (Nb) 比每代 Ne 更容易。我们使用最近开发的模型 (agene) 和已发表的 63 种多次生育的动植物重要生命表数据，对生活史与 Ne、Nb 和成年种群数量 (N) 比率之间的关系进行了实证评估。Nb/Ne 在物种间变化惊人，达到了六倍，与预期相反，超过一半的物种的 Nb 大于 Ne。Nb/Ne 的变化有多达三分之二和 Ne/N 的变化有一半可以用两个长期以来既引起生态学家又引起进化生物学家兴趣的生活史特征（成熟年龄和成年寿命）来解释。这些结果为不同类群的种群和进化过程之间的联系提供了新的见解，并证明了它们之间存在紧密的一般联系。我们的结果首次使得有可能根据基于每代 Ne 的丰富进化理论背景来解释迅速积累的 Nb 估计值。
