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Genetic basis of female sexual preference in a stalk-eyed fly

茎眼果蝇雌性性偏好的遗传基础

基本信息

批准号：
NE/G00563X/1
负责人：
Kevin Fowler
金额：
$ 62.9万
依托单位：
University College London
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2009
资助国家：
英国
起止时间：
2009 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FG00563X%2F1
关键词：
Genetic basis female sexual preference

项目摘要

There is considerable interest amongst the general public and scientists in understanding how exaggerated male sexual ornaments have evolved through female mate preferences. Much recent interest in sexual selection has been directed toward understanding the causes of variation in male ornaments, both genetic and environmental, and the signalling value of these traits. In contrast, there has been a neglect of in depth studies of variation in female sexual preferences. This in part reflects the difficulty of accurately quantifying preferences - which requires repeated measures of female responses to a variety of male stimuli, which are often difficult to study under laboratory conditions. It also reflects a general under appreciation of the variability and complexity of female preference behaviour. We have already developed an excellent system for quantifying variation in female mate preference in the African stalk-eyed fly Diasemopsis meigenii. In this species, females actively reject unwanted male mating attempts. This has allowed us to develop protocols to accurately measure individual female mate preferences. We have previously demonstrated that the strength of preference varies positively with phenotypic variation in female eyespan and female fecundity. A key question to address is the genetic underpinnings of variation in female mate preferences. Without genetic variation female preference cannot evolve. We will carry out the first QTL (quantitative trait locus) study of the genetics of preference. This will uncover the number of separable genetic factors underlying variation in preference. It may be that there are one or two genetic factors with major effects or alternatively a more even distribution of effect sizes of genes across the genome. It will also reveal the linkage pattern of preference genes and whether there is a bias towards the X-chromosome, as some theory predicts. Another critical issue that we will investigate is the evidence that preferences are condition-dependent. Several recent studies have shown that females reared under good conditions in which high quality resources are freely available have different preferences than females reared on poor quality resources. For example, in our previous work, we have shown that female stalk-eyed flies with access to better larval or adult resources have stronger directional preferences for males with larger sexual ornaments. This has wide ranging implications for the strength of sexual selection, if the females with the highest condition not only show the greatest discrimination of who they mate with but are also the most fecund. We will investigate the genetics of condition-dependent preferences using a quantitative genetic study. Genetically related families will be raised in three environments which vary in food quality. It is possible that the environmental variation will overwhelm the genetic signal. But from our previous studies measuring the responses of male traits to environmental stress, we do not expect this. Rather we believe that the harsh environment will amplify genetic differences between females, bringing out genetic variation in preference. So some female genotypes will consistently produce strong preference in all environments, whereas others genotypes will show declining preference as environmental conditions deteriorate. We will further probe this prediction in our QTL study. We have already shown that the strength of female preference in stalk-eyed flies covaries with female eyespan and female fertility, two traits that strongly reflect resources available during larval and adult development respectively. We will test whether QTL for female preference are located in the same genomic regions as QTL for female eyespan and QTL for female fecundity. This pattern could indicate that the same genes for condition underlie several traits such as preference, eyespan and fecundity.

公众和科学家对了解夸张的男性性饰物是如何通过女性择偶偏好而演变的非常感兴趣。最近对性选择的兴趣主要集中在了解雄性饰物变异的原因（遗传和环境）以及这些性状的信号价值。相比之下，人们却忽视了对女性性偏好变化的深入研究。这在一定程度上反映了准确量化偏好的困难——这需要重复测量女性对各种男性刺激的反应，而这通常很难在实验室条件下进行研究。它还反映出人们普遍低估了女性偏好行为的可变性和复杂性。我们已经开发了一个优秀的系统来量化非洲茎眼蝇 Diasemopsis meigenii 雌性交配偏好的变化。在这个物种中，雌性会主动拒绝雄性不想要的交配尝试。这使我们能够开发出准确测量女性择偶偏好的方案。我们之前已经证明，偏好的强度与女性眼跨和女性生育力的表型变化呈正相关。需要解决的一个关键问题是女性择偶偏好差异的遗传基础。如果没有遗传变异，女性偏好就无法进化。我们将开展第一个偏好遗传学的QTL（数量性状位点）研究。这将揭示偏好变化背后的可分离遗传因素的数量。可能存在一两个具有重大影响的遗传因素，或者基因组中基因的影响大小分布更均匀。它还将揭示偏好基因的连锁模式以及是否存在对 X 染色体的偏见，正如一些理论预测的那样。我们将调查的另一个关键问题是偏好取决于条件的证据。最近的几项研究表明，在免费提供优质资源的良好条件下抚养的女性与在劣质资源下抚养的女性有不同的偏好。例如，在我们之前的工作中，我们已经表明，能够获得更好的幼虫或成虫资源的雌性茎眼果蝇对具有较大性装饰物的雄性具有更强的方向性偏好。如果条件最高的雌性不仅对交配对象表现出最大的歧视性，而且繁殖力也最强，那么这对性选择的强度具有广泛的影响。我们将使用定量遗传学研究来研究条件依赖性偏好的遗传学。具有遗传相关性的家庭将在三种食物质量不同的环境中长大。环境变化可能会压倒遗传信号。但从我们之前测量男性特征对环境压力反应的研究来看，我们并没有预料到这一点。相反，我们认为恶劣的环境会放大雌性之间的遗传差异，带来偏好的遗传变异。因此，一些女性基因型在所有环境中都会始终产生强烈的偏好，而其他基因型则会随着环境条件的恶化而表现出逐渐下降的偏好。我们将在 QTL 研究中进一步探讨这一预测。我们已经表明，雌性对茎眼果蝇的偏好强度与雌性眼距和雌性生育力共同变化，这两个特征分别强烈反映了幼虫和成虫发育过程中可用的资源。我们将测试雌性偏好的 QTL 是否与雌性眼跨的 QTL 和雌性生育力的 QTL 位于相同的基因组区域。这种模式可能表明，相同的条件基因是多种性状的基础，例如偏好、眼跨度和繁殖力。