From molecules to societies and back again: the relationship between social evolution and genome evolution

从分子到社会再返回：社会进化与基因组进化之间的关系

• 批准号: RGPIN-2015-05871
• 负责人: Zayed, Amro
• 金额: $ 2.77万
• 依托单位: York University
• 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=687119
• 关键词: molecules; societies; back; again; relationship

The rise of sociality represented a major transition in evolution that puzzled biologists for centuries. Social insects exhibit reproductive altruism: workers forgo reproduction to help their mother reproduce. Current theories for how and why sociality evolved assume a simple model of evolution where the evolution of sociality proceeds independently of genome evolution. However, there is a growing body of evidence showing that derived features of social insect genomes reflect changes caused by sociality. Does social behaviour alter patterns of genome evolution in ways that can enhance or, in some cases, limit the spread of social alleles? ******Our group has led pioneering studies that linked features of genome structure with the evolution of worker traits in honey bees. Over the next five years, we plan to uncover the missing links between social evolution and genome evolution by answering the following questions:******1) Does sociality increase genetic loads? Social populations are predicted to have large reductions in effective size, which weakens the strength of natural selection. As a consequence, social genomes are expected to harbour more slightly deleterious mutations that reduce fitness (i.e. higher genetic load). We will compare genetic diversity and the frequency of deleterious mutations in the sequenced genomes of many social and solitary insects to test this hypothesis. ******2) Does sociality increase mutation rates and biases? Queens tend to be long lived and tend to have high rates of meiotic recombination; both features are expected to influence the mutational process - a fundamental evolutionary parameter. We will quantify and contrast mutational biases in social versus solitary insect genomes. We will also directly estimate the mutation rate in honey bee genomes and study if mutation is linked to high recombination and/or high longevity.******3) Does the sex-determination load limit the evolution of sociality? Ants, bees and wasps have a form of sex determination that imposes a substantial genetic load in small populations. This genetic load may limit or reverse the evolution of sociality: we will test this hypothesis using simulation models that explicitly account for sex determination during social evolution. ******4) What is the mechanistic and evolutionary basis of kin-recognition in bees? We will study this precursor trait for social evolution using a novel combination of targeted genome sequencing, chemical analysis of hydrocarbon scent cues, and behavioral assays of honey bee workers. ******My proposed research has a great potential for changing the way biologists think about sociality by illuminating how social behaviour influences patterns of genome evolution that `feedback' and alter the evolutionary trajectory of social populations. The transformational research proposed herein will help us understand both the rise and rarity of sociality in animals.**

社会性的兴起代表了一个令生物学家困惑了几个世纪的重大进化转变。群居昆虫表现出生殖利他主义：工蜂放弃繁殖来帮助它们的母亲繁殖。目前关于社会性如何以及为什么进化的理论假设了一个简单的进化模型，其中社会性的进化独立于基因组进化进行。然而，越来越多的证据表明，社会性昆虫基因组的衍生特征反映了社会性引起的变化。社会行为是否会以某种方式改变基因组进化模式，从而增强或在某些情况下限制社会等位基因的传播？******我们的团队领导了一些开创性的研究，将基因组结构特征与蜜蜂工蜂特征的进化联系起来。在接下来的五年里，我们计划通过回答以下问题来揭示社会进化和基因组进化之间缺失的联系：******1)社会性增加遗传负荷吗？预计社会人口的有效规模将大幅减少，这削弱了自然选择的力量。因此，社会基因组预计会包含更多降低适应性的轻微有害突变（即更高的遗传负荷）。我们将比较许多群居昆虫和独居昆虫的基因多样性和有害突变的频率，以验证这一假设。******2)社会性会增加突变率和偏见吗？蜂王往往寿命长，减数分裂重组率高；这两个特征预计都会影响突变过程——一个基本的进化参数。我们将量化和对比群居昆虫与独居昆虫基因组的突变偏差。我们还将直接估计蜜蜂基因组的突变率，并研究突变是否与高重组和/或长寿有关。******3)性别决定负荷是否限制了社会性进化？蚂蚁、蜜蜂和黄蜂有一种性别决定的形式，在小种群中施加了大量的遗传负荷。这种基因负荷可能限制或逆转社会性的进化：我们将使用模拟模型来验证这一假设，该模型明确说明了社会进化过程中的性别决定。******蜜蜂近亲识别的机制和进化基础是什么？我们将使用靶向基因组测序、碳氢化合物气味线索的化学分析和蜜蜂工蜂行为分析的新组合来研究这种社会进化的前兆特征。******我提出的研究有很大的潜力改变生物学家思考社会性的方式，通过阐明社会行为如何影响基因组进化的模式，从而“反馈”并改变社会群体的进化轨迹。本文提出的变革性研究将帮助我们理解动物社会性的兴起和稀有