CAREER: Ecological Speciation and Heterogeneous Genomic Differentiation in Hybridizing Haplodiploids

据估计，地球上有900万种生物，它们的习性和外貌各不相同。为了解释这种多样性，科学家们研究了新物种是如何形成的，并描述了它们之间的差异是如何积累的。大多数科学家都认为，适应不同的栖息地往往会引发新物种的形成。然而，物种形成的遗传原因和后果仍然是一个谜。该项目利用了两种以松树为食的害虫，它们在物种形成过程中被“当场捕获”。红松锯蝇与白松锯蝇在自然界中杂交水平较低，但两者之间存在许多差异。这表明物种的形成并不完全。对不同松树的适应似乎是减少这些物种之间基因交换的关键因素。实验室杂交和田间试验将用于确定负责不同松木适应性的遗传区域。结果将揭示这些差异如何影响这些物种在野外的基因交换率。这项工作将为保护生物多样性和防治害虫提供必要的知识。此外，本项目将开发综合研究/教学项目，为公众和多样化的本科生提供科学体验。了解生态物种形成的遗传基础需要确定基因型、生殖隔离和全基因组遗传分化之间的联系。本项目利用了这对寄主利用特性和繁殖障碍不同的杂交锯蝇物种。首先，QTL定位方法将遗传变异与寄主偏好和寄主性能性状的变异联系起来。其次，实地诱捕实验将寄主偏好表型与成虫栖息地隔离联系起来。第三，通过田间试验对寄主植物和寄主利用性状进行调控，将寄主性能性状与适合度和生殖隔离联系起来。第四，对这些物种重叠和分离的种群对进行全基因组重测序，将揭示分化的人口统计学历史和遗传分化模式。互补的教育工作将培训公民科学家捕捉和识别锯蝇，培训非stem学生筛选样本并解释诊断性PCR分析。这些数据将用于评估杂交的时空变化。此外，STEM学生将参与连接基因型，表型，适应性，生殖隔离和分化的现场和实验室实验。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

There are an estimated nine million species on earth, with diverse habits and appearances. To explain this diversity, scientists examine how new species form and describe how differences accumulate between them. Most scientists agree that adaptation to different habitats frequently initiates the formation of new species. The genetic causes and consequences of species formation, however, remain a mystery. This project takes advantage of two pine tree-feeding insect pests that are "caught in the act" of species formation. Although there are many differences between them, the redheaded-pine sawfly and the white-pine sawfly interbreed at low levels in nature. This suggests that species formation is not quite complete. Adaptation to different pines appears to be a key factor that reduces gene exchange between these species. Laboratory crosses and field experiments will be used to identify the genetic regions responsible for different pine adaptations. The results should reveal how these differences affect rates of gene exchange between these species in the wild. This work will provide essential knowledge for preserving biodiversity and combatting pests. Additionally, this project will develop integrated research/teaching projects that provide scientific experiences for the public and diverse undergraduates. Understanding the genetic basis of ecological speciation requires identifying links among genotypes, reproductive isolation, and genome-wide genetic differentiation. This project takes advantage of this pair of hybridizing sawfly species that differ in host-use traits and reproductive barriers. First, a QTL mapping approach will link genetic variation to variation in host-preference and host-performance traits. Second, a field trapping experiment will link host-preference phenotypes to adult habitat isolation. Third, a field experiment manipulates both the host plants and host-use traits to link host-performance traits to fitness and reproductive isolation. Fourth, full-genome re-sequencing of overlapping and isolated pairs of populations of these species will reveal the demographic history of divergence and patterns of genetic differentiation. The complementary educational efforts will train citizen scientists to trap and identify sawflies and non-STEM students to screen samples and interpret a diagnostic PCR assay. Together, these data will be used to evaluate spatial and temporal variation in hybridization. Additionally, STEM students will participate in field and lab experiments that connect genotype, phenotype, fitness, reproductive isolation, and differentiation.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.