Adaptation is mediated by phenotypic traits that are often near continuous, and undergo selective pressures that may change with the environment. The dynamics of allelic frequencies at underlying quantitative trait loci (QTL) depend on their own phenotypic effects, but also possibly on other polymorphic loci affecting the same trait, and on environmental change driving phenotypic selection. Most environments include a substantial component of random noise, characterized both by its magnitude and its temporal autocorrelation, which sets the timescale of environmental predictability. I investigate the dynamics of a mutation affecting a quantitative trait in an autocorrelated stochastic environment that causes random fluctuations of an optimum phenotype. The trait under selection may also exhibit background polygenic variance caused by many polymorphic loci of small effects elsewhere in the genome. In addition, the mutation at the QTL may affect phenotypic plasticity, the phenotypic response of given genotype to its environment of development or expression. Stochastic environmental fluctuations increase the variance of the evolutionary process, with consequences for the probability of a complete sweep at the QTL. Background polygenic variation critically alters this process, by setting an upper limit to stochastic variance of population genetics at the QTL. For a plasticity QTL, stochastic fluctuations also influences the expected selection coefficient, and alleles with the same expected trajectory can have very different stochastic variances. Finally, a mutation may be favored through its effect on plasticity despite causing a systematic mismatch with optimum, which is compensated by evolution of the mean background phenotype.

中文翻译：

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随机波动环境中 QTL 的选择性扫描。


适应是由表型性状介导的，这些性状通常接近连续，并承受可能随环境变化的选择压力。基础数量性状基因座 (QTL) 等位基因频率的动态取决于其自身的表型效应，但也可能取决于影响相同性状的其他多态性基因座，以及驱动表型选择的环境变化。大多数环境都包含随机噪声的重要组成部分，其特征在于其幅度和时间自相关性，这决定了环境可预测性的时间尺度。我研究了在自相关随机环境中影响数量性状的突变的动态，该环境导致最佳表型的随机波动。选择中的性状还可能表现出由基因组中其他地方的许多小影响的多态位点引起的背景多基因变异。此外，QTL 的突变可能会影响表型可塑性，即给定基因型对其发育或表达环境的表型反应。随机环境波动增加了进化过程的方差，从而影响了 QTL 完全清除的概率。背景多基因变异通过设定 QTL 群体遗传学随机方差的上限，严重改变了这一过程。对于可塑性 QTL，随机波动也会影响预期选择系数，具有相同预期轨迹的等位基因可能具有非常不同的随机方差。最后，尽管会导致与最佳值的系统失配，但突变可能会通过其对可塑性的影响而受到青睐，这可以通过平均背景表型的进化来补偿。