Institute of Ecology and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, United Kingdom.
Department of Aquaculture and Fish Biology, Háskólinn á Hólum, Hólum í Hjaltadal, Sauðárkrókur 551, Iceland.
Proc Natl Acad Sci U S A. 2024 Sep 10;121(37):e2410324121. doi: 10.1073/pnas.2410324121. Epub 2024 Sep 4.
A central goal in evolutionary biology is to understand how different evolutionary processes cause trait change in wild populations. However, quantifying evolutionary change in the wild requires linking trait change to shifts in allele frequencies at causal loci. Nevertheless, datasets that allow for such tests are extremely rare and existing theoretical approaches poorly account for the evolutionary dynamics that likely occur in ecological settings. Using a decade-long integrative phenome-to-genome time-series dataset on wild threespine stickleback (), we identified how different modes of selection (directional, episodic, and balancing) drive microevolutionary change in correlated traits over time. Most strikingly, we show that feeding traits changed by as much 25% across 10 generations which was driven by changes in the genetic architecture (i.e., in both genomic breeding values and allele frequencies at genetic loci for feeding traits). Importantly, allele frequencies at genetic loci related to feeding traits changed at a rate greater than expected under drift, suggesting that the observed change was a result of directional selection. Allele frequency dynamics of loci related to swimming traits appeared to be under fluctuating selection evident in periodic population crashes in this system. Our results show that microevolutionary change in a wild population is characterized by different modes of selection acting simultaneously on different traits, which likely has important consequences for the evolution of correlated traits. Our study provides one of the most thorough descriptions to date of how microevolutionary processes result in trait change in a natural population.
进化生物学的一个核心目标是了解不同的进化过程如何导致野生种群中特征的变化。然而，要量化野外的进化变化，就需要将特征变化与因果基因座上等位基因频率的变化联系起来。然而，允许进行这种测试的数据集极其罕见，现有的理论方法也不能很好地解释可能在生态环境中发生的进化动态。我们利用一个长达十年的、关于野生三刺鱼（）的综合表型到基因组的时间序列数据集，确定了不同的选择模式（定向选择、间歇性选择和平衡选择）如何随着时间的推移驱动相关特征的微观进化变化。最引人注目的是，我们发现，在 10 代的时间里，摄食特征发生了高达 25%的变化，这是由遗传结构的变化（即摄食特征的基因组育种值和基因座等位基因频率的变化）驱动的。重要的是，与摄食特征相关的基因座的等位基因频率的变化速度大于漂变预期的速度，这表明观察到的变化是定向选择的结果。与游泳特征相关的基因座的等位基因频率动态似乎受到波动选择的影响，在这个系统中，周期性的种群崩溃就证明了这一点。我们的研究结果表明，野生种群中的微观进化变化的特点是不同的选择模式同时作用于不同的特征，这可能对相关特征的进化有重要影响。我们的研究提供了迄今为止对微观进化过程如何导致自然种群中特征变化的最全面描述之一。
