Genomic dissection of climate change impacts on a declining Antarctic top predator population

气候变化对南极顶级捕食者数量下降影响的基因组剖析

• 批准号: 424119118
• 负责人: Professor Dr. Joseph Hoffman
• 金额: --
• 依托单位: British Antarctic Survey
• 依托单位国家: 德国
• 项目类别: Infrastructure Priority Programmes
• 财政年份: 2019
• 资助国家: 德国
• 起止时间: 2018-12-31 至 2023-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/424119118?language=en
• 关键词: Genomic; dissection; climate; change; impacts

Predicting how species will respond to climate change requires an understanding of the genetic basis of variation in individual fitness. This is particularly important for long-lived species, which have relatively few generations in which to respond, and species inhabiting polar regions where many of the most rapid and profound environmental changes are occurring. However, long-term studies of polar vertebrates are rare owing to the difficulty and expense of collecting individual-based phenotypic and genetic data from large numbers of individuals under challenging field conditions.Rapid climate change is likely to impose strong selection pressures on traits that are important to fitness, yet few empirical studies have been able to directly quantify altered selective regimes under climate change and their demographic consequences. Furthermore, most studies have focused on additive genetic effects (i.e. allele frequency changes) in response to climate change. However, there is a growing awareness of the fact that heterozygosity can also be a major component of individual fitness that feeds into population growth and extinction probability.An outstanding opportunity to elucidate the genomic and phenotypic consequences of altered selective regimes under climate change is provided by a study of Antarctic fur seals in the South Atlantic. We recently reported a 25% decline in the number of breeding females and an 8% fall in pup birth mass since the 1980s due to locally reduced krill availability. Concurrently, breeding female heterozygosity has increased by 17% over two decades, suggesting that the strength of viability selection against homozygous pups has been increasing over time. However, because heterozygosity was only quantified from nine genetic markers, it remains unclear whether these patterns could reflect inbreeding depression or chance linkage of individual markers to biologically relevant genes. Elucidating the importance of these mechanisms and identifying the genes involved is crucial for understanding the nature of selection, the genetic architecture of fitness-relevant traits and their ecological and evolutionary dynamics in a changing world.We will tackle this question by genotyping 576 individuals spanning three decades at 80,000 genome-wide distributed single nucleotide polymorphisms. The resulting dataset will offer great power to quantify the contribution of inbreeding depression to fitness variation, while several complementary approaches will also be taken to evaluate the explanatory power of specific parts of the genome and the possible involvement of key candidate genes. Finally, we will delve deeper into early acting fitness variation by testing whether heterozygosity influences the ability of individual pups to gain body mass during the critical period from birth to nutritional independence. This project will thereby provide an unprecedented window on the impacts of climate change on an Antarctic top predator.

预测物种将如何应对气候变化需要了解个体适应性变异的遗传基础。这对寿命较长的物种尤其重要，因为它们的后代相对较少，而生活在极地地区的物种正在发生许多最迅速和最深刻的环境变化。然而，由于在具有挑战性的野外条件下从大量个体收集基于个体的表型和遗传数据的困难和费用，对极地脊椎动物的长期研究很少。快速的气候变化可能会对对适应性很重要的性状施加强大的选择压力，但很少有实证研究能够直接量化气候变化下改变的选择制度及其人口后果。此外，大多数研究都集中在气候变化的加性遗传效应（即等位基因频率变化）上。然而，越来越多的人意识到，杂合性也可能是个体适应度的一个主要组成部分，它会影响种群的增长和灭绝概率。对南大西洋南极海豹的研究为阐明气候变化下改变的选择制度的基因组和表型后果提供了一个绝佳的机会。我们最近报告说，自20世纪80年代以来，由于当地磷虾供应减少，繁殖雌性数量下降了25%，幼崽出生质量下降了8%。同时，雌性的杂合度在过去20年中增加了17%，这表明对纯合子幼崽的生存力选择的强度随着时间的推移而增加。然而，由于杂合度仅从9个遗传标记中量化，因此尚不清楚这些模式是否反映了近交抑制或单个标记与生物学相关基因的偶然连锁。阐明这些机制的重要性和识别相关基因对于理解选择的本质、适应性相关性状的遗传结构及其在不断变化的世界中的生态和进化动力学至关重要。我们将解决这个问题，通过基因分型576个人跨越30年，在8万个全基因组分布的单核苷酸多态性。由此产生的数据集将为量化近亲繁殖抑制对适应度变化的贡献提供强大的力量，同时还将采用几种互补方法来评估基因组特定部分的解释力和关键候选基因的可能参与。最后，我们将通过检验杂合性是否会影响幼崽在从出生到营养独立的关键时期获得体重的能力，来深入研究早期适应性变化。因此，这个项目将为气候变化对南极顶级捕食者的影响提供一个前所未有的窗口。