Genotype x environment interaction and the evolution of sexually-selected traits

基因型x环境相互作用和性选择特征的进化

• 批准号: 0516634
• 负责人: Michael Greenfield
• 金额: --
• 依托单位: University of Kansas Center for Research Inc
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-08-01 至 2011-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0516634&HistoricalAwards=false
• 关键词: Genotype; environment; interaction; evolution; sexually

Genotype x Environment Interaction and the Evolution of Sexually Selected TraitsThe presence of genetic variation for male sexual traits such as mating signals remains a major problem in evolutionary biology. Female choice often favors exaggerated mating signals and is thereby expected to reduce genetic variation greatly, yet recent surveys indicate that substantial variation remains in many species. This problem has been addressed in an acoustic pyralid moth, the lesser wax moth (Achroia grisella), in which males broadcast an ultrasonic mating song attractive to females up to several meters distant. Playback experiments show that female lesser wax moths prefer male songs that are distinguished by several key features, and breeding experiments demonstrate substantial genetic variance, and heritability, for these song features. Additional breeding experiments and tests with inbred lines indicate that genetic tradeoffs between life history characters and male song attractiveness are not responsible for maintaining this variance. That is, attractive singers are larger, do not take longer to attain that size, survive longer, and spend more time singing on nightly and lifetime bases. On the other hand, environmental variation over space and time, combined with interactions between genotypes and the environment, may contribute to the genetic variance observed for male song attractiveness: Certain lines exhibit superior attractiveness when developing under a favorable environmental regime but show marked declines under stress, while other lines exhibit only modest performance in favorable environments but show little reduction in stress; that is, no one genetic variant exhibits the superior performance in all environments. However, these findings have thus far been restricted to observations of highly inbred or artificially selected laboratory populations, and the actual significance of environmental variation and genotype x environment interaction for maintaining genetic variance in natural populations is unknown. In this project researchers will extend the aforementioned studies in an important way by determining whether: (1) the range of responses to environmental gradients; and (2) the environmental variation that actually occur in the field are likely to maintain the levels of genetic variance observed for male song attractiveness. In particular, they will determine whether the level of genetic variance reflects the amount of environmental variation a population has experienced, and whether genetic variants that exhibit maximum attractiveness in both favorable and stressful environments occur. The two co-Principal Investigators will also determine whether variation in female preference for male signals, and the response of the female preference trait to environmental variation, contribute to genetic variance for male song attractiveness. This possibility will be augmented via a parallel molecular genetic (quantitative trait locus, QTL) analysis of inbred lines in which they will examine the covariance between genes that influence male song and female preference traits. Overall, the project emphasizes the complex interplay between genes and the environment that can shape animal behavior. The focus on GEI will help direct the attention of biologists toward more realistic studies of mating behavior and away from tendencies toward 'typological' thinking with regard to signals and preferences. The QTL analysis will represent one of the first applications of this powerful genetic tool for investigating the genetic bases of intra-specific differences in traits responsible for mate choice. In addition, the project will involve undergraduate and graduate students and postdoctoral scientists who will be trained in the study of acoustic communication and evolutionary genetics. Students attending the N.S.F. Research Experiences for Undergraduates (REU) program offered during the summer by the Department of Ecology and Evolutionary Biology at the University of Kansas will do independent studies related to the proposed research. Moths from the various lines will be made available for laboratories in various undergraduate biology classes.

基因x环境相互作用与性选择序列的进化雄性性征的遗传变异，如交配信号的存在，仍然是进化生物学中的一个主要问题。雌性选择往往倾向于夸大的交配信号，因此有望大大减少遗传变异，但最近的调查表明，许多物种仍然存在巨大的变异。这个问题已经在一种有声的吡喃蛾身上得到了解决，小蜡蛾(Achroia Grisella)是一种小蜡蛾，雄性在几米远的地方播放一种吸引雌性的超声波交配歌曲。回放实验表明，雌性小蜡蛾更喜欢有几个关键特征的雄性歌曲，繁殖实验表明，这些歌曲特征的遗传变异和遗传力很大。另外的育种实验和对近交系的测试表明，生活史特征和男性歌曲吸引力之间的遗传权衡并不是维持这种差异的原因。也就是说，有魅力的歌手体型更大，不需要更长的时间就能达到这样的体型，生存时间更长，而且每晚和终生都要花更多的时间唱歌。另一方面，环境在空间和时间上的变化，以及基因和环境之间的相互作用，可能有助于观察到男性歌曲吸引力的遗传差异：某些品系在有利的环境条件下发育时表现出优越的吸引力，但在胁迫下表现出明显的衰退，而另一些品系在有利的环境中表现平平，但压力几乎没有减少；也就是说，没有一个遗传变异在所有环境中都表现出优越的表现。然而，到目前为止，这些发现仅限于对高度近亲繁殖或人工选择的实验室种群的观察，环境变异和基因x环境交互作用对维持自然种群遗传变异的实际意义尚不清楚。在这个项目中，研究人员将以一种重要的方式扩展前述研究，确定：(1)对环境梯度的反应范围；以及(2)现场实际发生的环境变化可能保持观察到的男性歌曲吸引力的遗传差异水平。特别是，他们将确定遗传变异的水平是否反映了一个种群经历的环境变异的数量，以及是否出现了在有利和压力环境中都表现出最大吸引力的遗传变异。两位共同首席调查员还将确定女性对男性信号的偏好变化，以及女性偏好特征对环境变化的反应，是否会导致男性歌曲吸引力的遗传差异。这种可能性将通过对自交系进行平行的分子遗传(数量性状基因座，QTL)分析来扩大，在这种分析中，他们将检查影响男性歌曲和女性偏好特征的基因之间的协方差。总体而言，该项目强调了可以塑造动物行为的基因和环境之间的复杂相互作用。对GEI的关注将有助于将生物学家的注意力引导到对交配行为的更现实的研究上，而不是倾向于关于信号和偏好的类型学思维。QTL分析将是这种强大的遗传工具在研究负责配偶选择的性状的种内差异的遗传基础方面的首批应用之一。此外，该项目将涉及本科生和研究生以及博士后科学家，他们将接受声学通信和进化遗传学研究的培训。参加由堪萨斯大学生态与进化生物学系在夏季提供的NS.F.为本科生提供的研究体验(REU)项目的学生将进行与拟议研究相关的独立研究。各行各业的飞蛾将被提供给各个本科生生物班的实验室。