Collaborative Proposal: Selection and Genetic Succession in the Intertidal -- Population Genomics of Pisaster ochraceus During a Wasting Disease Outbreak and its Aftermath

这个项目试图通过探索最近的一次大流行来了解捕食者-疾病动力学的结果。2013年，北太平洋东部发生了一场大流行，导致90%的赭海星(Pisaster Ochraceus)死亡。研究小组将探索复苏可能如何依赖于往往难以看到的过程，如海洋物种迁徙和自然选择的相互作用。虽然由于几年来异常高的招募人数，海星的数量目前正在反弹，但海星消耗症继续保持在较低的水平。该项目旨在确定大流行和随后恢复的遗传后果。该团队将确定大多数易受影响的海星是否已经死亡，并确定易受影响的海星存活的可能避难所。他们将检查对这种疾病抵抗力的可遗传变异的可能性，以评估新兵是否容忍或容易消瘦。解决这些问题将使人们能够预测他们的康复轨迹和对未来大规模疾病爆发的潜在反应。研究成果将在一个合作研讨会上与资源经理和科学家分享，该研讨会将侧重于推进海洋疾病研究的最先进方法。公众将有机会通过与加州大学西摩海洋发现中心的合作，了解更多关于海星衰弱疾病的信息，并可以使用www.seastarwasting.org上提供的在线互动地图来跟踪疾病的发病率。结果将被纳入CalTeach的教师专业发展中，并适用于大学以下的教材。该项目将培训不同的早期职业科学家-本科生、研究生和博士后学者-整合生态学和基因组方法。在地理异质性和海洋pH和温度的长期变化的更广泛背景下理解大规模流行病的后果是一个新出现的当代问题。该项目使用海星衰减病(SSWD)暴发的种群动态和遗传后果的长期表征，以估计该物种可能面临的长期后果。SSWD暴发导致东北太平洋赭鱼种群平均90%的死亡率。虽然有记录的最大规模的新兵涌入发生在2014-2016年间，但尚不清楚他们来自哪里，新兵和幸存的成年人是否仍然容易感染这种持续在低水平的疾病，以及这些动态可能会持续多久。这一长期数据集为探索这种大规模疾病暴发的短期和长期影响及其引发的人口动态提供了独特的机会。该项目建立在对野生种群的长期实地研究的基础上，以描述寄主种群动态、疾病和基因组多样性。其目标是发现与SSWD相关的遗传变异，并将这种变异与可归因于非生物环境变异的种群基因组效应分离。目标是：(1)在其范围内的24个地点进行种群普查，以描述种群动态、SSWD的流行情况，并测量非生物变量。(2)结合RNAseq分析进行实验室实验，以确定在SSWD、温度、盐度和PCO2异常暴露期间差异调节的基因座。(3)将ddRAD、RNAseq和选择中的候选基因座定位到赭鱼基因组。(4)进行为期3年的大范围种群基因组分析，以评估在野生捕获的非生物变异的地理马赛克上有无SSWD的标本之间的遗传(SNP)变异。(5)探索SSWD与候选基因座之间的联系，如EF1a。这些分析将描述疾病暴发的直接基因组后果、暴发引发的人口动态以及影响这些变化的因素和机制的相互作用--如疾病、温度、迁徙、选择。这些结果将促进对塑造沿海生态系统种群基因组结构的一般过程和相互作用的理解，为未来在设计沿海生物资源管理战略方面的研究和应用提供资源。

This project seeks to understand the outcomes of predator-disease dynamics by exploring a recent pandemic that decimated 90% of ochre sea stars (Pisaster ochraceus) in the eastern North Pacific in 2013. The research team will explore how recovery may depend upon often difficult-to-see processes such as the interplay of migration and natural selection in marine species. While the population of sea stars is currently rebounding due to several years of unusually high recruitment, the sea star wasting disease continues to persist at low levels. This project aims to determine the genetic consequences of the pandemic and subsequent recovery. The team will determine whether the majority of susceptible sea stars have died and identify possible refuges where susceptible sea stars survived. They will examine the potential for heritable variation in resistance to this disease in order to assess whether the new recruits are tolerant or susceptible to wasting. Resolving these issues will enable predictions about the trajectory of their recovery and the potential responses to future large scale disease outbreaks. Research findings will be shared with resource managers and scientists at a collaborative workshop that will focus on state-of-the-art methods to advance research on marine diseases. The public will have the opportunity to learn more about sea star wasting disease through a partnership with the UCSC Seymour Marine Discovery Center and can track the incidence of disease using an online interactive map available at www.seastarwasting.org. Results will be incorporated into professional development for teachers with CalTeach and adapted for teaching materials up to college-level. This project will train diverse early career scientists - undergraduates, graduates, and a postdoctoral scholar - in integration of ecological and genomic methods.Understanding the consequences of large-scale pandemics in the broader contexts of geographic heterogeneity and chronic changes in ocean pH and temperature is an emerging contemporary issue. This project employs long-term characterization of population dynamics and genetic consequences of a sea star wasting disease (SSWD) outbreak, which caused median 90% mortality in Pisaster ochraceus populations in the northeastern Pacific, to estimate potential long-term consequences for the species. While the largest recorded influx of new recruits occurred in 2014-2016, it is unknown where they originated from, whether recruits and surviving adults remained susceptible to the disease, which persisted at low levels, and for how long these dynamics might continue. This long-term dataset provides a unique opportunity for exploring the short and long term repercussions of such large-scale disease outbreaks and the population dynamics that they precipitate. This project builds on long-term field studies of wild populations to describe host population dynamics, the disease, and genomic diversity. The goal is to discover genetic variation associated with SSWD and to dissociate that variation from population genomic effects attributable to abiotic environmental variation. Objectives are: (1) Census P. ochraceus at 24 sites throughout its range to describe population dynamics, the prevalence of SSWD, and measure abiotic variables. (2) Conduct laboratory experiments coupled with RNAseq analyses to determine loci differentially regulated during exposure to SSWD, temperature, salinity, and pCO2 anomalies. (3) Map ddRAD, RNAseq, and candidate loci under selection to a P. ochraceus genome. (4) Conduct range-wide population genomic analyses for 3 years to assess genetic (SNP) variation among wild-caught specimens with, versus without, SSWD across a geographic mosaic of abiotic variation. (5) Explore links between SSWD and candidate loci, such as EF1A. These analyses will describe the immediate genomic consequences of the disease outbreak, the population dynamics that the outbreak set in motion, and the interplay of factors and mechanisms - such as disease, temperature, migration, selection - that affected these changes. The results will advance understanding of general processes and interactions that shape population genomic structure in coastal ecosystems, providing resources to inform future research and applications in design of management strategies for coastal living resources.