Understanding genetic variation and adaptation in relation to sexual reproduction

了解与有性生殖相关的遗传变异和适应

• 批准号: RGPIN-2015-05387
• 负责人: Agrawal, Aneil
• 金额: $ 5.81万
• 依托单位: University of Toronto
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=692089
• 关键词: Understanding; genetic; variation; adaptation; relation

Some of the most prolific plant and animal species reproduce clonally much of the time, using sexual reproduction only rarely. My group will examine the consequences of evolving with little or no sex as well as investigate the conditions favouring the maintenance of sex, using a combination of theoretical, expermimental, and genomic approaches. The empirical work will use two facultatively sexual systems, duckweeds and monogonont rotifers.*** We will develop theory to understand how asexuals evolve in fluctuating environments, with special emphasis on temporal autocorrelations in selection. We will test these ideas experimentally using obligately asexual clones of the rotifer Brachionus calyciflorus. In another set of experiments, we will build upon our past work demonstrating that adaptation to environmental change can select for higher rates of sex within facultatively sexual populations. Specifically, we will extend and test theory predicting that population subdivision favours higher rates of sex during adaptation.*** In addition to well-controlled lab experiments with rotifers, we will examine the causes and consequences of sex in a natural system by studying duckweeds. We have already obtained substantial genomic data from two species (Lemna minor and Spirodela polyrhiza) and this will allow us to make progress rapidly. We will extend statistical methods for inferring rates of sex using sequence data and apply these to our duckweed data. Using existing methods of population genetics inference, we will estimate the efficacy of selection from genomic data in different populations and species and relate these measures to inferred rates of sex, testing the prediction that sex increases the efficacy of selection across the genome.***Duckweed will also be used to test theory on the evolutionary maintenance of sex. By experimentally creating clonally-derived genotypes as well as sexually-derived genotypes, we will compare the fitness distributions of genotypes from different reproductive modes. This type of data is key to inferring which of two general population genetic mechanisms favour sex. We will assay fitness under several different field-manipulated environments to assess the importance of ecological agents (e.g., natural enemies) that are typically excluded in lab experiments but critical to some hypotheses.***Numerous high quality training opportunities will be provided for undergrads, grads, and PDFs.********

一些最多产的植物和动物物种大多数时候都是无性繁殖，很少使用有性繁殖。我的小组将研究很少或没有性的进化的后果，以及调查有利于维持性的条件，使用理论，实验和基因组方法的结合。实验工作将使用两种官能性系统，浮萍和单殖体轮虫。*我们将发展理论来理解无性恋者如何在波动的环境中进化，特别强调选择中的时间自相关性。我们将用萼花臂尾轮虫的专性无性克隆来验证这些想法。在另一组实验中，我们将建立在我们过去的工作基础上，证明适应环境变化可以选择在官能性人群中更高的性比率。具体来说，我们将扩展和测试预测人口细分有利于适应期间更高的性行为率的理论。* 除了对轮虫进行严格控制的实验室实验外，我们还将通过研究浮萍来研究自然系统中性别的原因和后果。我们已经从两个物种（浮萍和多根螺旋藻）获得了大量的基因组数据，这将使我们能够迅速取得进展。我们将使用序列数据扩展推断性别比率的统计方法，并将其应用于我们的浮萍数据。使用现有的群体遗传学推断方法，我们将从不同群体和物种的基因组数据中估计选择的功效，并将这些措施与推断的性别比率联系起来，测试性别增加整个基因组选择功效的预测。浮萍也将被用来检验性别进化维持的理论。通过实验创建克隆衍生的基因型以及性衍生的基因型，我们将比较来自不同繁殖模式的基因型的适应度分布。这种类型的数据是推断两种一般人群遗传机制中哪一种有利于性别的关键。我们将在几个不同的现场操作环境下测定适应性，以评估生态因子的重要性（例如，天敌），通常在实验室实验中被排除在外，但对某些假设至关重要。将为本科生、毕业生和PDF提供许多高质量的培训机会。*