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Collaborative Research: Does genetic load drive mating system evolution? Tests in an explicit historical context

合作研究：遗传负荷是否驱动交配系统进化？

基本信息

批准号：
1457037
负责人：
Jeremiah Busch
金额：
$ 34.2万
依托单位：
Washington State University
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2015
资助国家：
美国
起止时间：
2015-08-01 至 2019-07-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1457037&HistoricalAwards=false
关键词：
Collaborative Research Does genetic load

项目摘要

This research will quantify the interplay between historical events and current natural selection in shaping plant mating system. Evolution is an ongoing process but depends strongly on the past. While nearly everyone acknowledges this fact, it has been difficult to quantify the relative importance of historical and current selection pressures as explanations of patterns in nature. This research will look at the factors that have determined the amount of self-pollination versus outcrossing in the American bellflower (Campanulastrum americanum). The project will immerse undergraduate and graduate students in the collection of next-generation DNA sequence data to reconstruct historical events and studies of current selective environment in the study species. Analyses of data from these disparate sources into a single, unified framework will provide a clearer understanding of the processes shaping complex patterns in nature, and yields a predictive framework that can be applied in any biological system. Broad dissemination of this predictive approach is valuable because it will help predict the response of species to increasingly altered environments in the modern age.Plant mating systems are evolutionarily labile, ranging from highly outcrossing to highly inbreeding. This wide variation provides an excellent system for understanding the ultimate drivers of evolutionary change. Variable mating system strategies across levels of the biological hierarchy are commonly explained as adaptations to the current selective environment. A significant fraction of this variation, however, may reflect historical evolution in response to colonization during range expansion. This idea will be tested using Campanulastrum americanum, a North American herb in which preliminary data indicate reduced inbreeding depression and greater autogamy in sites where phylogeographic data suggest recent colonization. Using populations a range of distances from glacial refugia, the researchers will gather data with coalescent analysis of RAD-seq polymorphism, greenhouse studies of fixed and segregating genetic load, field studies of pollen limitation and reproductive assurance, and population-genetic inferences of selfing rates. Analyses of these data will determine whether initially non-adaptive processes associated with range expansion provided a permissive environment for later evolution of the mating system. The research framework therefore provides a mechanism for discerning the ultimate drivers of organismal change across past and present time scales.

这项研究将量化历史事件和当前自然选择在塑造植物交配系统中的相互作用。进化是一个持续的过程，但强烈依赖于过去。虽然几乎每个人都承认这一事实，但很难量化历史和当前选择压力作为自然界模式解释的相对重要性。这项研究将着眼于决定美国风铃草（Campanulastrum americanum）自花授粉与异交数量的因素。该项目将使本科生和研究生沉浸在下一代DNA序列数据的收集中，以重建历史事件和研究物种当前选择环境的研究。将这些不同来源的数据分析到一个统一的框架中，将使人们更清楚地了解自然界中形成复杂模式的过程，并产生一个可应用于任何生物系统的预测框架。这种预测方法的广泛传播是有价值的，因为它将有助于预测物种对现代日益变化的环境的反应。植物交配系统在进化上是不稳定的，从高度异交到高度近亲繁殖。这种广泛的差异为理解进化变化的最终驱动力提供了一个极好的系统。在生物等级的不同层次上，可变的交配系统策略通常被解释为对当前选择性环境的适应。然而，这种变化的一个重要部分，可能反映了历史的演变，在范围扩大殖民化。这一想法将使用Campanulastrum americanum进行测试，这是一种北美草药，初步数据表明，在地理数据表明最近殖民化的地点，近亲繁殖衰退减少，自花受精增加。使用距离冰川避难所一系列距离的人群，研究人员将通过RAD-seq多态性的结合分析，固定和分离遗传负荷的温室研究，花粉限制和生殖保证的实地研究以及自交率的群体遗传推断来收集数据。这些数据的分析将确定是否最初的非适应性过程与范围的扩大提供了一个宽松的环境，为以后的交配系统的演变。因此，该研究框架提供了一种机制，用于识别过去和现在时间尺度上生物体变化的最终驱动因素。