The genomic and adaptive consequences of extreme, human-mediated population decline

人类介导的人口极端减少的基因组和适应性后果

• 批准号: 2885540
• 金额: --
• 依托单位: Bangor University
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2885540
• 关键词: genomic; adaptive; consequences; extreme; human

The consequences of severe population decline in wild organisms are poorly understood. Survival of species experiencing such declines may be hampered by a limited ability to adapt to changing environments, reduced fertility and greater susceptibility to disease - all stemming from low genetic diversity. When applied to systems that have experienced population bottlenecks as a result of human activities, genomic tools allow us to examine the genomic consequences in terms of inbreeding, genetic load, disease resistance and adaptability. Our aim is to understand the consequences of extreme, rapid population decline using an example of drastic human intervention in which the fish stocks of entire lakes were eradicated and repopulated.The introduction of the salmonid ectoparasite Gyrodactylus salaris to Norway resulted in the collapse of wild Atlantic salmon populations. Consequently, authorities applied Rotenone - a broad-spectrum biocide - to entire river catchments to kill all fish hosts. Once treated, waterways are restocked with uninfected captive-bred juveniles from local fish stocks. In 2012 the Fusta catchment (four linearly-connected sub-arctic lakes) underwent a rotenone program. Prior to treatment, fish communities included inter-lake migratory brown trout. Genetic assessment revealed significant population structure and a high proportion of anadromous trout caught at sea could be assigned to Fusta populations. Furthermore, these analyses detected loci under selection suggesting local adaptation across the system. Brown trout and the anadromous form, in particular, have experienced substantial declines in recent years and such treatments may threaten the genetic health of brown trout. This system represents a unique opportunity to understand (i) the impact of extreme bottlenecks on the genome of a species, (ii) how loss of genetic diversity influences immunity to parasites and (iii) the processes by which rapid adaptation occurs in genetically depauperate populations.

人们对野生生物种群数量严重下降的后果知之甚少。经历这种衰退的物种的生存可能会受到适应不断变化的环境的能力有限、生育力下降和对疾病的更易感性的阻碍——所有这些都源于遗传多样性低。当应用于因人类活动而经历种群瓶颈的系统时，基因组工具使我们能够检查近亲繁殖、遗传负荷、抗病性和适应性方面的基因组后果。我们的目的是通过人类剧烈干预的例子来了解人口极端快速下降的后果，其中整个湖泊的鱼类种群被消灭并重新繁殖。鲑鱼体外寄生虫 Gyrodactylus salaris 引入挪威导致野生大西洋的崩溃鲑鱼种群。因此，当局在整个河流流域使用了鱼藤酮（一种广谱杀菌剂）来杀死所有鱼类宿主。经过处理后，水道将重新放养来自当地鱼类种群的未受感染的圈养幼鱼。 2012 年，福斯塔流域（四个线性连接的亚北极湖泊）实施了鱼藤酮计划。在处理之前，鱼类群落包括湖间洄游的褐鳟鱼。遗传评估揭示了显着的种群结构，并且在海上捕获的溯河产卵鳟鱼的很大一部分可以归入 Fusta 种群。此外，这些分析检测到选择下的基因座，表明整个系统的局部适应。近年来，褐鳟尤其是溯河产卵的鳟鱼数量大幅下降，这种治疗方法可能会威胁到褐鳟的遗传健康。该系统提供了一个独特的机会来了解（i）极端瓶颈对物种基因组的影响，（ii）遗传多样性的丧失如何影响对寄生虫的免疫力，以及（iii）遗传退化种群中快速适应的过程。