Mechanisms promoting speciation with gene flow in host-specialized haplodiploids

进化生物学中持续时间最长的争论之一是新物种是否可以在相互交换基因的同时形成。基因交换被认为使物种形成困难，因为它混合了遗传背景。这种混合防止了物种之间差异的积累。然而，遗传学数据告诉我们，自然界中许多物种确实会交换基因。这个项目的目标是了解一些物种如何能够承受基因交换。为了做到这一点，该项目的重点是一对松树喂养昆虫物种，这是在美国东部常见的害虫。这两个物种适应不同的松树品种，并在整个历史中交换基因。通过关注未成熟和成熟的生命阶段以及两性，该项目将更完整地了解如何适应不同的环境产生新物种。通过填补我们对新物种如何产生的理解的空白，这项工作将加深我们对周围世界的理解。这些知识将帮助我们保护生物多样性和防治害虫。此外，研究人员将利用他们的项目开发教育材料，用于向一年级生物学学生教授遗传学和进化论。该项目还将为数十名学生提供参与真实科学研究的机会。这些经验可以帮助我们留住STEM学科的优秀学生。 进化理论预测，物种形成与基因流是困难的，但经验数据表明，这种分歧的情况是常见的性质。为了调和这些看似矛盾的发现，这项工作利用了一对实验上容易处理的松叶蜂物种（Neodiprion lecontei和N.松属），适应不同的松树，并有特殊的基因组资源，广泛的互补数据，并与基因流的分歧的历史。首先，幼虫的饮食操作的焦点物种和他们的互惠的男性和女性的杂种将被用来量化生殖隔离的所有组合的宿主植物和评估的作用，促进物种形成的表型可塑性与基因流。第二，幼虫转录组的两个物种和他们的互惠第一代杂交饲养的双亲主机将被用来揭示不同的转录反应幼虫饮食有助于宿主适应和基因错误表达的杂交种。第三，数量性状基因座定位在第二代杂交雄性饲养的双亲主机将被用来描述宿主依赖和主机独立的杂交活力，幼虫的性能，和成年男性形态的遗传结构。因为这项工作提供了直观的例子，说明表型变异的复杂性和自然选择产生新物种的机制，从拟议的工作的数据将被用来开发一个案例研究和科学家聚光灯用于介绍生物学课程，并燃料学生-该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的智力价值进行评估来支持和更广泛的影响审查标准。

One of the longest running debates in evolutionary biology is whether new species can form while exchanging genes with one another. Gene exchange is thought to make species formation difficult because it mixes up genetic backgrounds. This mixing prevents the buildup of differences between species. Nevertheless, genetic data tell us that many species do exchange genes in nature. The goal of this project is to understand how some species can withstand gene exchange. To do so, this project focuses on a pair of pine-feeding insect species that are common pests in the eastern United States. These two species are adapted to different pine species and have exchanged genes throughout their history. By focusing on immature and adult life stages and both sexes, this project will produce a more complete picture of how adaptation to different environments produces new species. By filling gaps in our understanding of how new species arise, this work will deepen our understanding of the world around us. This knowledge will help us preserve biodiversity and combat pests. Additionally, the researchers will use their project to develop educational materials for teaching genetics and evolution to first-year Biology students. This project will also provide opportunities for dozens of students to participate in authentic scientific research. Such experiences can help us retain talented students in STEM disciplines. Evolutionary theory predicts that speciation with gene flow is difficult, yet empirical data indicate such divergence scenarios are common in nature. To reconcile these seemingly contradictory findings, the proposed work takes advantage of an experimentally tractable pair of pine sawfly species (Neodiprion lecontei and N. pinetum) that are adapted to different pines and have exceptional genomic resources, extensive complementary data, and a history of divergence with gene flow. First, larval diet manipulations of the focal species and their reciprocal male and female hybrids will be used to quantify reproductive isolation on all combinations of host plants and to evaluate the role of phenotypic plasticity in promoting speciation with gene flow. Second, larval transcriptomes of the two species and their reciprocal first-generation hybrids reared on both parental hosts will be used to uncover how divergent transcriptional responses to larval diet contribute to host adaptation and gene misexpression in hybrids. Third, quantitative trait locus mapping in second-generation hybrid males reared on both parental hosts will be used to describe the genetic architecture of host-dependent and host-independent hybrid viability, larval performance, and adult male morphology. Because this work provides intuitive examples of the complexity of phenotypic variation and mechanisms through which natural selection produces new species, data from the proposed work will be used to develop a case study and scientist spotlights for use in introductory Biology courses and to fuel student-driven research.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.