The genetics and genomics of adaptive sex ratio behaviour

适应性性别比行为的遗传学和基因组学

• 批准号: NE/J024481/1
• 负责人: David Shuker
• 金额: $ 47.45万
• 依托单位: University of St Andrews
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2013
• 资助国家: 英国
• 起止时间: 2013 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FJ024481%2F1
• 关键词: genetics; genomics; adaptive; sex; ratio

We will examine the genetic basis of sex ratio behaviour in the parasitoid wasp Nasonia vitripennis. Female N. vitripennis facultatively change their offspring sex ratios in line with Hamilton's theory of Local Mate Competition (LMC). LMC arises from competition between related males (e.g. brothers) for mates, and can occur when mating occurs in localised groups, for instance amongst groups of kin. When LMC is intense (e.g. if all males are brothers), the optimal sex ratio is a female-biased one. This bias reduces competition amongst sons and increases the number of mates for those sons. As LMC declines, so does the predicted sex ratio bias. The degree of LMC depends on how many females lay eggs on a patch of hosts (and how many eggs they lay). Over the last decade, we have explored the cues female Nasonia use when allocating sex under LMC. With a robust theoretical framework, we now have a remarkably good understanding of facultative sex allocation under LMC at the phenotypic level in Nasonia. However, our understanding of the genetics of sex ratio is more rudimentary, especially in terms of the mechanism of sex allocation. Thus far, we have some picture of the quantitative genetics of sex ratio in Nasonia (estimates of heritability, input of new mutations, and the identification of four Quantitative Trait Loci, or QTL). We have also begun to explore what genes are expressed during oviposition. In this proposal, we will build on this work to explore the genetic basis of sex ratio variation and control in Nasonia, using three complementary approaches.First, we will first follow-up our recent QTL study using a Restriction Site Associated DNA sequencing ("RAD-seq") approach and a repeat of the cross between High and Low sex ratio lines drawn from the same natural population. RAD-seq can generate thousands of markers across a genome enabling finer-scale QTL mapping projects. We will also use the data we generate to test for clutch size variation QTL, testing for loci pleiotropically influencing both sex ratio and clutch size.Second, we will follow-up our recent gene expression work to explore changes in gene expression associated with exposure to different LMC environments and different combinations of LMC cues. Back in 2004, Shuker & West experimentally showed that female Nasonia vitripennis responded differentially to "host" versus "social" LMC cues. We will follow a similar protocol, assaying the transcriptomes of the focal females using RNA-seq on the Illumina platform. Our aim is to see whether we can link patterns of gene expression to subtle environmental differences which we know have a big effect on the sex ratio phenotype.Third, we will test whether or not epigenetic modifications of DNA (specifically DNA methylation) are associated with the regulation of sex ratio behaviour. The extent to which epigenetic control of gene expression influences behaviour is currently the focus of much interest, both in humans and other vertebrates, but also increasingly in insects. First, we will look for patterns of differential methylation associated with either mating (as females switch from mate-searching to host-searching) and/or interactions with LMC cues whilst ovipositing. Second, we will disrupt DNA methylation and look for changes in sex allocation. If DNA methylation helps regulate gene networks associated with sex ratio behaviour, then we will see patterns of differential methylation across the treatments in the first experiment and changes in sex allocation across the treatments in the second.Taken together, these approaches will address both the genetic architecture of sex ratio variation and also the genes and gene pathways associated with sex allocation, and whether or not the regulation of those pathways involves DNA methylation. They will provide complementary sets of candidate genes, enabling the functional genomic/molecular evolution studies required to fully realise the genotype-phenotype link.

我们将研究寄生蜂性比行为的遗传基础。根据汉密尔顿的本地配偶竞争理论(LMC)，雌性北极星天牛兼性地改变其后代的性别比例。LMC源于近亲雄性(例如兄弟)之间对配偶的竞争，当交配发生在局部群体中时，例如在亲属群体之间。当LMC很激烈时(例如，如果所有男性都是兄弟)，最理想的性别比例是女性偏向的性别比例。这种偏见减少了儿子之间的竞争，增加了儿子的配偶数量。随着LMC的下降，预测的性别比偏差也会下降。LMC的程度取决于多少雌性在一块寄主上产卵(以及它们产卵的数量)。在过去的十年里，我们探索了雌性Nasony在LMC下分配性行为时使用的线索。有了一个强大的理论框架，我们现在对纳索尼亚的LMC下的兼性性别分配在表型水平上有了一个非常好的理解。然而，我们对性别比例的遗传学的理解还比较初级，特别是在性别分配机制方面。到目前为止，我们已经对纳斯尼亚的性别比的数量遗传学有了一些了解(遗传力的估计，新突变的输入，以及四个数量性状基因座的鉴定，或QTL)。我们还开始探索在产卵过程中表达哪些基因。在这项建议中，我们将在这项工作的基础上，使用三种互补的方法来探索纳斯尼亚种群性别比变异和控制的遗传基础。首先，我们将首先使用限制位点相关DNA测序(RAD-SEQ)方法来跟踪我们最近的QTL研究，并重复来自同一自然群体的高和低性别比系之间的杂交。RAD-SEQ可以在基因组中生成数千个标记，从而实现更精细的QTL定位项目。我们还将使用我们生成的数据来测试产卵量变异QTL，测试多效性影响性别比和产卵量的基因座。其次，我们将继续我们最近的基因表达工作，探索与暴露于不同LMC环境和不同LMC线索组合相关的基因表达变化。早在2004年，Shuker&West就通过实验证明，雌性纳索尼亚·维特里帕尼斯对“主人”和“社交”LMC暗示的反应是不同的。我们将遵循类似的方案，在Illumina平台上使用RNA-seq分析焦点雌性的转录本。我们的目的是看看我们是否可以将基因表达模式与我们知道对性别比表型有很大影响的细微环境差异联系起来。第三，我们将测试DNA的表观遗传修饰(特别是DNA甲基化)是否与性别比行为的调节有关。基因表达的表观遗传控制对行为的影响程度目前是人们非常感兴趣的焦点，对人类和其他脊椎动物来说都是如此，在昆虫中也是如此。首先，我们将寻找与交配(雌性从寻找配偶转向寻找寄主)和/或产卵时与LMC线索相互作用相关的差异甲基化模式。其次，我们将扰乱DNA甲基化，并寻找性别分配的变化。如果DNA甲基化有助于调节与性别比行为相关的基因网络，那么我们将在第一个实验中看到不同处理的甲基化模式，并在第二个处理中看到性别分配的变化。总而言之，这些方法将研究性别比变异的遗传结构，以及与性别分配相关的基因和基因途径，以及这些途径的调节是否涉及DNA甲基化。它们将提供一组互补的候选基因，使功能基因组/分子进化研究得以充分实现基因-表型之间的联系。

项目成果

DNA methylation changes induced by long and short photoperiods in Nasonia.

鼻孔长和短光周期引起的DNA甲基化变化。

• DOI: 10.1101/gr.196204.115
• 发表时间: 2016-02
• 期刊: Genome research
• 影响因子: 7
• 作者: Pegoraro M;Bafna A;Davies NJ;Shuker DM;Tauber E
• 通讯作者: Tauber E

Differential gene expression is not required for facultative sex allocation: a transcriptome analysis of brain tissue in the parasitoid wasp Nasonia vitripennis.

• DOI: 10.1098/rsos.171718
• 发表时间: 2018-03
• 期刊: Royal Society open science
• 影响因子: 3.5
• 作者: Cook N;Boulton RA;Green J;Trivedi U;Tauber E;Pannebakker BA;Ritchie MG;Shuker DM
• 通讯作者: Shuker DM

Additional file 5 of Genomics of sex allocation in the parasitoid wasp Nasonia vitripennis

寄生蜂 Nasonia vitripennis 性别分配基因组学附加文件 5

• DOI: 10.6084/m9.figshare.12680599
• 发表时间: 2020
• 作者: Pannebakker B

Oviposition but Not Sex Allocation Is Associated with Transcriptomic Changes in Females of the Parasitoid Wasp Nasonia vitripennis.

• DOI: 10.1534/g3.115.021220
• 发表时间: 2015-10-28
• 期刊: G3 (Bethesda, Md.)
• 作者: Cook N;Trivedi U;Pannebakker BA;Blaxter M;Ritchie MG;Tauber E;Sneddon T;Shuker DM
• 通讯作者: Shuker DM