Engen Steinar, Kvalnes Thomas, Sæther Bernt-Erik
Centre for Biodiversity Dynamics, Department of Mathematical Sciences, , Norwegian University of Science and Technology, N-7491, Trondheim, Norway.
Evolution. 2014 Sep;68(9):2509-23. doi: 10.1111/evo.12456. Epub 2014 Jun 20.
An extension of the selection differential in the Robertson-Price equation for the mean phenotype in an age-structured population is provided. Temporal changes in the mean phenotype caused by transient fluctuations in the age-distribution and variation in mean phenotype among age classes, which can mistakenly be interpreted as selection, will disappear if reproductive value weighting is applied. Changes in any weighted mean phenotype in an age-structured population may be decomposed into between- and within-age class components. Using reproductive value weighting the between-age class component becomes pure noise, generated by previous genetic drift or fluctuating selection. This component, which we call transient quasi-selection, can therefore be omitted when estimating age-specific selection on fecundity or viability within age classes. The final response can be computed at the time of selection, but can not be observed until lifetime reproduction is realized unless the heritability is one. The generality of these results is illustrated further by our derivation of the selection differential for the continuous time age-structured model with general age-dependent weights. A simple simulation example as well as estimation of selection components in a house sparrow population illustrates the applicability of the theory to analyze selection on the mean phenotype in fluctuating age-structured populations.
本文给出了罗伯逊-普莱斯方程中年龄结构种群平均表型选择差的一种扩展形式。如果应用繁殖价值加权，由年龄分布的瞬时波动和年龄组间平均表型变化（可能被错误地解释为选择）引起的平均表型的时间变化将会消失。年龄结构种群中任何加权平均表型的变化都可以分解为年龄组间和年龄组内的成分。使用繁殖价值加权时，年龄组间成分就变成了由先前的遗传漂变或波动选择产生的纯噪声。因此，在估计年龄组内繁殖力或生存力的年龄特异性选择时，可以忽略这个我们称为瞬时准选择的成分。最终反应可以在选择时计算出来，但除非遗传力为1，否则在实现终生繁殖之前是无法观察到的。我们对具有一般年龄依赖权重的连续时间年龄结构模型的选择差的推导进一步说明了这些结果的普遍性。一个简单的模拟例子以及对家麻雀种群选择成分的估计说明了该理论在分析波动的年龄结构种群中平均表型选择方面的适用性。
