Genomic analysis of inbreeding, DNA methylation and sexual trait expression in a lekking bird

lekking 鸟近交、DNA 甲基化和性特征表达的基因组分析

• 批准号: 454606304
• 负责人: Professor Dr. Joseph Hoffman
• 金额: --
• 依托单位: Arbeitsgruppe Verhaltensforschung
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/454606304?language=en
• 关键词: Genomic; analysis; inbreeding; DNA; methylation

Since Darwin first coined the term “sexual selection” to explain the evolution of exaggerated male traits, we have come to understand the complex interrelationships among these traits, the information they encode and the life histories of the animals they are embedded into. Sexual selection is built on the idea that individual quality is signaled by the expression of these traits, yet a clear mechanistic understanding of the genetic architectures of sexual traits and the mechanisms regulating sexual trait expression remains elusive.We know that inbreeding is an important component of individual quality, and several studies have documented inbreeding depression for sexually-selected traits. Moreover, trait expression can be influenced by dynamic factors such as age and environmental variation, so epigenetic control mediated by body condition has been proposed as a means of regulating genotype-dependent sexual trait expression. Resolving long-standing evolutionary questions about mate choice and sexual selection therefore requires a fundamental understanding of the genetic and epigenetic basis of sexual traits.We will combine the genomic inference of inbreeding with genome-wide methylation analysis to investigate the genetic and epigenetic mechanisms affecting sexual trait expression and reproductive success in a classical lek model system, the black grouse. First, we will use precise genomic estimates of inbreeding to quantify the magnitude of inbreeding depression for multiple sexual traits. From there, we will use structural equation modeling to integrate potential pathways linking inbreeding-dependent sexual trait expression to variation in reproductive success.To shed light on the genetic architectures of sexual traits, we will quantify the contribution of different genomic regions to inbreeding depression. We will evaluate support for the ‘genic capture’ hypothesis, which posits that sexual traits are influenced by the cumulative effects of large numbers of loci distributed across the genome. Alternatively, localized genomic regions could be disproportionately important, e.g. gene pathways linked to immunity or metabolism.Finally, we will build upon a recent pilot study linking heterozygosity to sexual trait expression via differential methylation by using a cost-effective genome-wide assay, epi-GBS, to identify genome-wide epigenetic signatures associated with inbreeding and male sexual trait expression. We expect inbreeding-dependent DNA methylation patterns to be strongest during periods of maximal trait expression, to be localized to specific genomic regions, and to be trait-specific.In summary, our project tackles an important knowledge gap by combining detailed data from multiple sexual traits over individual lifespans with genomic and epigenetic data in a classical lekking species. This project has the unrivalled potential to transform our understanding of sexual selection and underpin the next generation of detailed studies.

自从达尔文首次创造了“性选择”这个术语来解释夸张的男性特征的进化以来，我们已经开始了解这些特征之间的复杂的相互关系，它们所编码的信息，以及它们所嵌入的动物的生活史。性别选择建立在这样一种观念上，即个体的质量是通过这些特征的表达来表示的，然而，对性别特征的遗传结构和性特征表达的调控机制的明确机械理解仍然是未知的。我们知道近亲繁殖是个体质量的重要组成部分，一些研究已经证明了近亲繁殖对性选择特征的抑制作用。此外，性状的表达会受到年龄和环境变化等动态因素的影响，因此，体况介导的表观遗传控制被认为是调节依赖于基因的性性状表达的一种手段。因此，解决长期存在的关于配偶选择和性选择的进化问题需要对性交的遗传和表观遗传基础有一个基本的了解。我们将把近亲交配的基因组推断与全基因组甲基化分析相结合，在经典的Lek模型系统--黑松鸡--中研究影响性特征表达和繁殖成功的遗传和表观遗传机制。首先，我们将使用对近亲交配的精确基因组估计来量化近亲交配对多种性征的抑制程度。从那时起，我们将使用结构方程模型来整合连接近亲繁殖依赖的有性特征表达和生殖成功变异的潜在途径。为了阐明有性特征的遗传结构，我们将量化不同基因组区域对近亲繁殖抑制的贡献。我们将评估对‘基因捕获’假说的支持，该假说认为，性别特征受分布于整个基因组的大量基因座累积效应的影响。最后，我们将在最近的一项试点研究的基础上，通过使用具有成本效益的全基因组分析(epi-GBS)将杂合性与性别特征表达联系起来，以识别与近亲繁殖和男性性别特征表达相关的全基因组表观遗传特征。我们预计近亲繁殖依赖的DNA甲基化模式在性状表达最高的时期最强，定位于特定的基因组区域，并具有性状特异性。总而言之，我们的项目通过将来自个体生命周期的多个性别特征的详细数据与经典物种的基因组和表观遗传学数据相结合，解决了一个重要的知识差距。这个项目具有无与伦比的潜力，可以改变我们对性选择的理解，并为下一代详细研究奠定基础。