THE GENETIC BASIS OF LOCAL ADAPTATION ACROSS AN ISLAND ADAPTIVE RADIATION

跨岛适应性辐射的局部适应的遗传基础

• 批准号: 2204729
• 负责人: Elizabeth Stacy
• 金额: $ 118.42万
• 依托单位: University of Nevada Las Vegas
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-05-15 至 2026-04-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2204729&HistoricalAwards=false
• 关键词: GENETIC; BASIS; LOCAL; ADAPTATION; ACROSS

Many species originate in dramatic bursts called adaptive radiations. How adaptive radiations generate spectacular numbers of species over short time periods is a fundamental question in evolutionary biology. Adaptive radiations in remote islands are especially fascinating, given that such radiations originate from founder populations with limited genetic variation, which is the raw material for evolution. Understanding the genetic basis of adaptive radiations on remote islands allows insight into not only the origin of species (and, hence, biodiversity), but also how species will respond to rapid climate change. This project will uncover the genetic basis of adaptation to extreme water availability (drought and flooding) in Metrosideros, an adaptive radiation of woody species that dominate Hawaii’s forests. The results will reveal how often recurring adaptation to very wet and very dry environments relies on the recycling of ancient genes present in the founder population versus new genes arising through mutation. Repeated adaptation through the recycling of ancient genes would help to explain how adaptive radiations occur and would suggest that species are able to adapt to rapid climate change. In particular, this project will reveal insights into how trees will cope with the increased drought and flooding expected with climate change. The project will also train one technician, 2 Ph.D. students, and several undergraduates in cutting-edge technologies and analyses, provide bioinformatics training to federal and state agency staff and students, faculty, and staff at two Minority-Serving Institutions, and develop G6-12 curriculum related to plant adaptation and response to climate change.The proposed research will apply an evolutionary systems biology approach to Hawaii’s landscape-dominant woody genus, Metrosideros, to characterize the genetic basis of local adaptation to water availability across an island adaptive radiation. The project will take advantage of the relatively small genome size and high-quality chromosome-level reference genome; parental, F1, and F2 lines; and population-level resequencing data available for Metrosideros to accomplish 3 aims: Aim 1) contrast seedling physiology and patterns of gene expression between replicate dry- and wet-adapted taxa in response to drought and water-logging, Aim 2) identify phenotypic traits and quantitative trait loci (QTL) for resistance to drought or water-logging and identify QTL that colocalize with differentially expressed genes (DEGs), and Aim 3) examine the evolution of the colocalized DEG-QTL regions (and non-intersecting, but significant QTL) across the Hawaiian Metrosideros adaptive radiation to test the prediction that recurring adaptation to parallel environments involves recurring selection on shared genomic regions of predominantly ancestral origin. By investigating the genetic basis of local adaptation across an island adaptive radiation, this project will help to solve the long-standing evolutionary problem of how spectacular phenotypic and ecological diversity can arise from founder populations with limited genetic variation. Specifically, results will reveal the degree to which recurring adaptation to parallel environments draws on the same genomic regions in different taxa and the relative importance of shared ancestral variation, introgression, and de novo mutations for parallel evolution within an isolated radiation.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.

许多物种起源于称为适应性辐射的戏剧性爆发。适应性辐射如何在短时间内产生惊人数量的物种是进化生物学中的一个基本问题。偏远岛屿上的适应性辐射尤其令人着迷，因为这种辐射来自遗传变异有限的创始人群体，这是进化的原材料。了解偏远岛屿适应性辐射的遗传基础，不仅可以洞察物种的起源(从而了解生物多样性)，还可以洞察物种将如何应对快速的气候变化。该项目将揭示大都会人种适应极端可用水(干旱和洪水)的遗传基础，大都市人是主导夏威夷森林的木本植物的一种适应性辐射。结果将揭示，在非常潮湿和非常干燥的环境中，反复适应依赖于创始人群体中存在的旧基因的循环，而不是通过突变产生的新基因。通过回收古代基因进行重复适应将有助于解释适应性辐射是如何发生的，并将表明物种能够适应快速的气候变化。特别是，这个项目将揭示树木将如何应对预计随着气候变化而增加的干旱和洪水。该项目还将在尖端技术和分析方面培训一名技术人员、两名博士生和几名本科生，为联邦和州机构的工作人员以及两所少数民族服务机构的学生、教职员工和工作人员提供生物信息学培训，并开发与植物适应和对气候变化的反应有关的G6-12课程。拟议的研究将把进化系统生物学方法应用于夏威夷以景观为主的木本植物--Metrosideros，以表征当地适应整个岛屿适应性辐射的水可获得性的遗传基础。该项目将利用相对较小的基因组大小和高质量的染色体水平的参考基因组；亲本、F1和F2系；目的1)比较苗木生理和干湿适应类群对干旱和内涝的反应，目的2)确定抗旱或涝的表型性状和数量性状基因座(QTL)，并找出与差异表达基因(Degs)共定位的QTL，以及目的3)研究夏威夷Metrosideros适应性辐射中共定位的DEG-QTL区域(和不相交但显著的QTL)的进化，以检验对平行环境的反复适应涉及主要起源于祖先的共享基因组区域的循环选择的预测。通过研究跨岛屿适应性辐射的局部适应的遗传基础，该项目将有助于解决长期存在的进化问题，即如何从遗传变异有限的创始人群体中产生壮观的表型和生态多样性。具体地说，结果将揭示对平行环境的反复适应在多大程度上依赖于不同分类群中的相同基因组区域，以及共享的祖先变异、渐渗和从头突变对于隔离辐射内的平行进化的相对重要性。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。