Reid Jane M, Acker Paul
Centre for Biodiversity Dynamics NTNU Trondheim 7491 Norway.
School of Biological Sciences University of Aberdeen Aberdeen AB24 2TZ United Kingdom.
Evol Lett. 2022 Apr 5;6(3):220-233. doi: 10.1002/evl3.278. eCollection 2022 Jun.
Successfully predicting adaptive phenotypic responses to environmental changes, and predicting resulting population outcomes, requires that additive genetic (co)variances underlying microevolutionary and plastic responses of key traits are adequately estimated on appropriate quantitative scales. Such estimation in turn requires that focal traits, and their underlying quantitative genetic architectures, are appropriately conceptualized. Here, we highlight that directly analyzing observed phenotypes as continuously distributed quantitative traits can potentially generate biased and misleading estimates of additive genetic variances and individual-by-environment and gene-by-environment interactions, and hence of forms of plasticity and genetic constraints, if in fact the underlying biology is best conceptualized as an environmentally sensitive threshold trait. We illustrate this scenario with particular reference to the key phenological trait of seasonal breeding date, which has become a focus for quantifying joint microevolutionary, plastic, and population responses to environmental change, but has also become a focus for highlighting that predicted adaptive outcomes are not always observed. Specifically, we use simple simulations to illustrate how potentially misleading inferences on magnitudes of additive genetic variance, and forms of environmental interactions, can arise by directly analyzing observed breeding dates if the transition to breeding in fact represents a threshold trait with latent-scale plasticity. We summarize how existing and new datasets could be (re)analyzed, potentially providing new insights into how critical microevolutionary and plastic phenological responses to environmental variation and change can arise and be constrained.
成功预测对环境变化的适应性表型反应，并预测由此产生的种群结果，需要在适当的定量尺度上充分估计关键性状的微进化和可塑性反应所基于的加性遗传（协）方差。而这种估计反过来又需要对重点性状及其潜在的数量遗传结构进行适当的概念化。在这里，我们强调，如果潜在生物学实际上最好被概念化为环境敏感阈值性状，那么将观察到的表型直接作为连续分布的数量性状进行分析，可能会对加性遗传方差、个体与环境以及基因与环境的相互作用产生有偏差和误导性的估计，从而对可塑性和遗传限制的形式产生偏差和误导性估计。我们以季节性繁殖日期这一关键物候性状为例来说明这种情况，该性状已成为量化对环境变化的联合微进化、可塑性和种群反应的重点，但也成为突出预测的适应性结果并非总是能观察到的重点。具体而言，我们使用简单模拟来说明，如果向繁殖的转变实际上代表具有潜在尺度可塑性的阈值性状，那么直接分析观察到的繁殖日期可能会对加性遗传方差的大小以及环境相互作用的形式产生潜在的误导性推断。我们总结了如何对现有和新数据集进行（重新）分析，这可能会为关键的微进化和可塑性物候对环境变异和变化的反应如何产生以及受到限制提供新的见解。
