Selection on heritable seasonal phenotypic plasticity of body mass
Selection on heritable seasonal phenotypic plasticity of body mass
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DOI：
10.1111/j.1558-5646.2007.00160.x
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发表时间：
2007-08-01
期刊：
影响因子：
3.3
通讯作者：
Festa-Bianchet, Marco
中科院分区：
文献类型：
--
作者：
Pelletier, Fanie;Reale, Denis;Festa-Bianchet, Marco
应对环境变化的能力是物种进化的基础。生物可以通过表型可塑性对季节环境变化做出反应。温带物种身体质量的巨大可塑性通常被认为是环境质量变化的简单结果，但也可能是为了适应季节性而进化的。以加拿大阿尔伯塔省公羊山野生大角羊母羊（Ovis canadensis）为研究对象，在两种不同的环境条件下，研究了其体重季节性可塑性的遗传基础和选择作用。可塑性的遗传力，估计为质量特定的夏冬质量变化，低但显著。在良好的环境条件下（种群数量增加，幼鱼存活率高），夏季相对质量变化的加性遗传变异分量大于恶劣的环境条件下（种群数量减少，幼鱼存活率低）。冬季相对质量变化的加性遗传变异与环境条件无关。我们发现了夏季（相对）和冬季（相对和绝对）质量变化的选择证据。对于一个给定的种群，更多的可塑性个体（具有更大的季节性种群变化）在下一年通过繁殖获得更大的适应性。然而，质量参数之间的遗传相关性为正。我们的研究支持这样的假设，即脊椎动物体重的季节性可塑性是一种适应，是在自然选择下进化而来的，以应对环境变化，但与其他特征的遗传相关性可能会限制其进化潜力。
The ability to cope with environmental change is fundamental to a species' evolution. Organisms can respond to seasonal environmental variation through phenotypic plasticity. The substantial plasticity in body mass of temperate species has often been considered a simple consequence of change in environmental quality, but could also have evolved as an adaptation to seasonality. We investigated the genetic basis of, and selection acting on, seasonal plasticity in body mass for wild bighorn sheep ewes (Ovis canadensis) at Ram Mountain, Alberta, under two contrasting environmental conditions. Heritability of plasticity, estimated as mass-specific summer and winter mass changes, was low but significant. The additive genetic variance component of relative summer mass change was greater under good environmental conditions (characterized by a population increase and high juvenile survival) than under poor conditions (population decrease and low juvenile survival). Additive genetic variance of relative winter mass change appeared independent of environmental conditions. We found evidence of selection on summer (relative) and winter (relative and absolute) mass change. For a given mass, more plastic individuals (with greater seasonal mass changes) achieve greater fitness through reproduction in the following year. However, genetic correlations between mass parameters were positive. Our study supports the hypothesis that seasonal plasticity in body mass in vertebrates is an adaptation that evolved under natural selection to cope with environmental variation but genetic correlations with other traits might limit its evolutionary potential.