Centre for Ecology and Conservation, University of Exeter, Cornwall, UK.
Department of Zoology, University of Cambridge, Cambridge, UK.
J Evol Biol. 2020 May;33(5):642-652. doi: 10.1111/jeb.13601. Epub 2020 Feb 27.
Genetic factors underpinning phenotypic variation are required if natural selection is to result in adaptive evolution. However, evolutionary and behavioural ecologists typically focus on variation among individuals in their average trait values and seek to characterize genetic contributions to this. As a result, less attention has been paid to if and how genes could contribute towards within-individual variance or trait 'predictability'. In fact, phenotypic 'predictability' can vary among individuals, and emerging evidence from livestock genetics suggests this can be due to genetic factors. Here, we test this empirically using repeated measures of a behavioural stress response trait in a pedigreed population of wild-type guppies. We ask (a) whether individuals differ in behavioural predictability and (b) whether this variation is heritable and so evolvable under selection. Using statistical methodology from the field of quantitative genetics, we find support for both hypotheses and also show evidence of a genetic correlation structure between the behavioural trait mean and individual predictability. We show that investigating sources of variability in trait predictability is statistically tractable and can yield useful biological interpretation. We conclude that, if widespread, genetic variance for 'predictability' will have major implications for the evolutionary causes and consequences of phenotypic variation.
如果自然选择要导致适应性进化，那么遗传因素是表型变异的基础。然而，进化和行为生态学家通常关注个体在平均特征值方面的差异，并试图描述这种差异的遗传贡献。因此，对于基因如何有助于个体内方差或特征“可预测性”，关注较少。事实上，表型“可预测性”在个体之间可能会有所不同，而来自家畜遗传学的新证据表明，这可能是由于遗传因素。在这里，我们使用野生型孔雀鱼的一个 pedigreed 群体中对行为应激反应特征的重复测量来进行实证检验。我们问：（a）个体之间是否存在行为可预测性的差异，以及（b）这种差异是否具有遗传性，并且在选择下是否可进化。我们使用数量遗传学领域的统计方法，为这两个假设提供了支持，并证明了行为特征均值与个体可预测性之间存在遗传相关结构。我们表明，研究特征可预测性的变异来源在统计学上是可行的，并且可以产生有用的生物学解释。我们的结论是，如果广泛存在，“可预测性”的遗传方差将对表型变异的进化原因和后果产生重大影响。
