OCE-PRF- Deleterious mutational load in climate driven marine range expansions

该奖项的全部或部分资金来自《2021年美国救援计划法案》(公法117-2)。随着全球变暖继续加速，物种范围在全球范围内以前所未有的速度扩大，海洋物种的扩张更是如此。一般来说，范围的扩大是通过一系列的殖民事件发生的，一波又一波地由几个分散的个体组成。这导致了一个新种群的建立，这个新种群起源于几个个体，导致了原始种群的遗传变异的一个小的非随机表示--这一过程被称为创始人效应。作为方正效应的结果，在范围边缘出现的有害突变分散到新扩大的栖息地，并可能在新种群中迅速增加频率(即扩大负荷)，导致适应度损失。这一过程在范围扩大期间得到了加强，这是因为存在较小的种群规模和较低的遗传变异来选择新的突变。捕鱼引发了类似的种群下降和遗传多样性降低的进化动态，同样增加了扩张负荷。海洋物种由于其高度的扩散能力而经历比陆地物种更快的范围扩展，并且受到捕捞压力的严重影响，然而，这两个过程的相互作用在海洋物种中尚未被阐明。量化有害突变的负载对于保护和管理至关重要，因为它们会限制种群的适应和生存。随着气候变化预计将继续下去，更多物种将以前所未有的速度经历范围转移，这使得记录当前的遗传多样性并了解处于扩大范围前沿的种群的遗传基础成为当务之急。该项目将资助一名NSF海洋科学博士后研究员的早期职业发展，并将支持该研究员的研究、培训、指导和专业发展。为加强这项工作的更广泛影响和效用，该研究员将向科学界、当地捕鱼界和渔业管理官员(例如，NOAA、Manomet、大西洋国家海洋渔业委员会)传播成果。此外，该项目将通过以下方式增加传统上代表性不足的群体对科学的参与：(1)本科生指导，(2)为当地社区大学的学生举办外展研讨会，以及(3)与当地社区的外展。在范围扩大的过程中，基因突变的快速积累--特别是边缘人群中的有害突变--在很大程度上仍未得到充分研究。这项研究提供了一个独特的机会来检验有害突变在快速气候驱动的范围扩大和捕捞的海洋鱼类黑海鲈鱼(Centropristis Striata)中积累的进化理论。使用全基因组数据、适应度测试和定量建模方法的组合，将检验以下假设：H1-(范围边缘的较高负载)C.striata将在范围扩展前沿的编码区显示比历史范围中心和边缘种群更大的扩展负载；H2-(范围边缘的适合度降低)扩展负载较大的范围扩展种群将显示出与适应度相关的特征降低的证据；H3-(捕捞加剧的负载)过度捕捞将加剧有害突变负载在扩展种群中的积累。如果结果如理论预测的那样支持假设(即，在扩展锋面发现更高的负荷和更低的适应性)，它们将对快速变化的气候下的海洋保护战略产生广泛的影响。然而，如果这些假设被否决，数据将挑战现有的科学假设，表明海洋系统经历了不同的过程。这一综合数据集将促进对气候驱动的范围扩大以及气候变化和捕捞压力对海洋物种(如黑海巴斯)的交互影响的理解。该奖项反映了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。

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2).Species range expansions are occurring across the globe at unprecedented rates as global warming continues to accelerate, and even more so in marine species. In general, range expansions occur by a series of colonization events in waves of a few dispersed individuals at a time. This leads to the establishment of a new population that originates from few individuals, resulting in a small non-random representation of the genetic variation from the original population – a process known as founder effect. As a result of founder effects, a deleterious mutation that arises at the range edge disperses to a newly expanded habitat and can rapidly increase in frequency within the new population (i.e., expansion load), leading to a loss in fitness. This process is enhanced during range expansion due to the small population sizes and low genetic variation present to select against the new mutation. Fishing triggers similar evolutionary dynamics of population declines and lower genetic diversity, similarly increasing expansion loads. Marine species experience faster range expansions than terrestrial species due to their high dispersal ability and are heavily impacted by fishing pressure, yet, the interaction of both these processes have yet to be elucidated in a marine species. Quantifying the load of deleterious mutations is critical for conservation and management, because they can limit a population’s adaptability and survival. With climate change expected to continue, more species will experience range-shifts at unprecedented rates, making it imperative to document current genetic diversity and understand the genetic basis of populations at the forefront of their expanded range. This project will fund the early career development of an NSF Ocean Sciences Postdoctoral Fellow and will support the research, training, mentorship, and professional development of the fellow. To enhance the broader impacts and utility of this work, the fellow will disseminate results to the scientific community, the local fishing community and fishery management officials (e.g., NOAA, Manomet, Atlantic States Marine Fisheries Commission). Additionally, this project will increase participation of traditionally underrepresented groups in science through: (1) undergraduate student mentorship, (2) outreach seminars for students in local community colleges, and (3) outreach with the local community.The rapid accumulation of genetic mutations – and in particular deleterious mutations in edge populations – remains largely understudied during range expansions. This study presents a unique opportunity to test the evolutionary theory of the accumulation of deleterious mutations in a rapid climate-driven range expansion and harvested marine fish, Black Sea Bass (Centropristis striata). Using a combination of genome-wide data, fitness tests, and quantitative modeling approaches, the following hypotheses will be tested: H1- (Higher load at range edge) C. striata will show a greater expansion load in coding regions at the range expansion front compared to the historical range center and edge populations; H2- (Decreased fitness at range edge) range expanding populations with a greater expansion load will show evidence of decreased fitness-related traits; H3- (Load exacerbated by fishing) overfishing will exacerbate the accumulation of deleterious mutational load in expanding populations. If results support the hypotheses (i.e., higher loads and decreased fitness are found at the expanding-front), as predicted by theory, they will have widespread implications for marine conservation strategies in a rapidly changing climate. However, if these hypotheses are rejected, the data will challenge existing scientific assumptions, suggesting marine systems undergo different processes. This integrative dataset will advance understanding of climate-driven range expansions and the interactive effects of climate change and fishing pressure on marine species, such as Black Sea Bass.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.