The role of contemporary evolution in shaping life history, demography and the fate of functional genetic variation in natural populations

进化生物学经历了一场小小的革命，最近的研究表明，自然选择的进化在野外只需几年或几十年就能被检测到。例如，有证据表明，由于全球变暖而进行的选择可以在基因水平上改变动物的繁殖时机。这就提出了关于当代自然种群快速进化的重要性和后果的重大问题，例如，进化如何有助于它们的短期适应，并改变诸如种群动态等生态过程。我的研究计划将利用系谱和分子数据，通过“实时”跟踪遗传变异，即逐代跟踪，来解决这些问题。我将以魁北克的法裔加拿大人为模型，研究生活史特征(如生育力、寿命)的进化。对于这个种群，可以获得跨越四个世纪的特殊数据，而且是长期动物数据集所无法比拟的。之前，我记录了140年来魁北克地区人口中女性首次生育年龄的微进化变化(即对自然选择的遗传反应)。有了我的发现基金，我将评估面临相似或不同环境条件的人群中这种进化反应的异质性。然后，我将量化生活史中的时间变化如何塑造人口统计学。快速的生活史进化也可能对功能上重要的遗传变异产生连锁效应。因此，我将开发一类新的模型，它将允许跨世代测量影响生物状况和寿命的变异的自然选择，将生活史的变化与遗传变异的频率动态联系起来。通过跟踪几代人之间的分子变化，我还将测试“母亲的诅咒”，这是一个重要的假设，可以部分解释许多物种中男性衰老更快、寿命更短的原因。因此，该方案将遵循一个逻辑顺序，通过研究反馈回路“生命-历史特征进化--人口学-变异频率-生命-历史特征进化”。它应该为当代进化如何塑造人口动态及其适应提供重要的见解。在现代生物有机体目前面临的全球环境变化的背景下，这一问题最为相关。

Evolutionary biology has undergone a small revolution with the recent demonstration that evolution by natural selection can be detected over just a few years or decades in the wild. For example, there is evidence that selection due to global warming can modify the timing of reproductive timing in animals at the genetic level. This raises major questions about the importance and consequences of rapid evolution in contemporary natural populations, e.g. how evolution contributes to their short-term adaptation and alters ecological processes such as population dynamics. My research programme will address these questions by following genetic variation “in real time”, namely generation-by-generation, using genealogical and molecular data. I will use the French-Canadian population from Québec as a model to study life-history traits (e.g., fertility, lifespan) evolution. Exceptional data spanning four centuries, and unequalled by long-term animal data sets, is available for this population. Previously, I documented a microevolutionary change (i.e. a genetic response to natural selection) in the age at first reproduction of women in a regional population from Québec over 140 years. With my Discovery Grant, I will assess the heterogeneity of such evolutionary responses across populations facing similar or different environmental conditions. I will then quantify how temporal changes in life history moulded the demography of populations. Rapid life history evolution can also have cascading effects on functionally important genetic variants. Hence, I will develop a new class of models that will allow the measurement, across generations, of natural selection on variants affecting organismal condition and lifespan, to link dynamically changes in life history to those in the frequency of genetic variants. By following molecular variation across generations, I will also test the “mother’s curse”, an important hypothesis that could partly explain the faster senescence and shorter lifespan of males in many species. This programme will thus follow a logical sequence by investigating the feedback loop “life-history trait evolution->demography->variant frequencies-> life-history trait evolution”. It should provide major insights into how contemporary evolution shapes the dynamics of population and their adaptation. This issue is most relevant within the context of global environmental changes that modern living organisms are currently facing.