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Adaptation and drift in the deep sea - investigating the evolution of diversity in a 'uniform' environment

深海的适应和漂移——研究“统一”环境中多样性的演变

基本信息

批准号：
NE/K005359/1
负责人：
Alan Hoelzel
金额：
$ 50.62万
依托单位：
Durham University
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2013
资助国家：
英国
起止时间：
2013 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FK005359%2F1
关键词：
Adaptation drift deep sea investigating

项目摘要

The conservation of biodiversity is necessary to provide natural populations with the potential to respond to a changing environment, and to prevent the loss of fitness associated with lost diversity. An understanding the underlying processes is necessary to promote effective transferable management strategies. This is especially important in the marine environment where there are few obvious boundaries to gene flow. Biodiversity is lost within populations by drift & directional selection, and retained among populations by the same processes. The size of insular populations helps to determine the dominant process, since drift is stronger than selection in small populations. It is known that much natural diversity is divided among conspecific populations by these processes, but the fragmented structure of this diversity is often cryptic, especially in poorly understood environments like the deep sea. We typically define populations a priori by geographic distance and according to apparent physical boundaries. However, in addition to spatial factors, environmental characteristics can affect patterns of connectivity by affecting the rate and direction of gene flow, and this influence will vary as environments change over time. Environmental characteristics also drive local selection, and selection can maintain differences among populations even with continuing gene flow. Without knowledge about how local populations may have adapted to local environments, we remain unable to incorporate that type of biodiversity into conservation strategy, and to address its potential importance to the long-term survival of species. Understanding the function and value of biodiversity requires a better understanding of the interacting processes of selection and drift leading to its evolution and loss. While much of the relevant theory is well established, empirical data are required to test theory and determine how environmental factors interact with evolutionary processes in natural systems. In this study we will employ second generation sequencing technologies to investigate how environmental factors are associated with the evolution of population structure and speciation in the deep sea, at both neutral and functional loci. The particular focus will be on habitat depth and isolation by distance, however other environmental factors will be quantified at collection sites based on data collected from the same sites during the recent ECOMAR consortium study (during which samples for the proposed study were collected). The study species will be fish in the genus Coryphaenoides, a specious genus of deep demersal fishes, some of which are commercially important fisheries species (including the primary focal species in this study, C. rupestris). Initial studies have shown phylogenetic lineage division correleted to habitat depth. Other work has indicated selection at genes associated with adaptation to pressure in some of these species. Two focal Coryphaenoides species will be investigated in a comparative population genomics study. These species, C. rupestris and C. brevibarbis are sympatric, but the former is found at shallower depths than the latter. We will test hypotheses about how habitat division by depth or other characteristics (e.g. current systems or geographic distance) may determine the evolution of intra- and inter-specific diversity (including among multiple habitat-specialist species in the genus using an extended phylogenetic assessment) both by drift (through differential environmental pressures associated with dispersal) and by selection. Greater connectivity is predicted in the abyssal habitat, which may lead to larger effective population sizes and facilitate adaptive evolution. Taken together these data will provide novel insight into the interactive role of drift and selection during the evolution of diversity, and transferable inference about how diversity is structured in the deep sea.

保护生物多样性是必要的，以提供自然种群的潜力，以应对不断变化的环境，并防止与失去多样性相关的健康损失。了解基本流程对于促进有效的可转移管理战略是必要的。这在海洋环境中尤其重要，因为基因流动几乎没有明显的界限。生物多样性在种群内通过漂移和定向选择丧失，在种群间通过相同的过程保留。岛屿种群的大小有助于确定优势过程，因为在小种群中，漂移比选择更强。众所周知，许多自然多样性是通过这些过程在同种种群之间划分的，但这种多样性的碎片化结构往往是神秘的，特别是在对深海等环境知之甚少的情况下。我们通常根据地理距离和明显的物理边界来先验地定义人口。然而，除了空间因素之外，环境特征还可以通过影响基因流动的速率和方向来影响连接模式，并且这种影响会随着环境的变化而变化。环境特征也驱动着地方选择，即使在基因持续流动的情况下，选择也可以保持种群之间的差异。如果不了解当地人口如何适应当地环境，我们仍然无法将这种类型的生物多样性纳入保护战略，并解决其对物种长期生存的潜在重要性。要了解生物多样性的功能和价值，就需要更好地了解导致生物多样性进化和丧失的选择和漂变的相互作用过程。虽然大部分相关理论已经建立，但需要经验数据来测试理论并确定环境因素如何与自然系统中的进化过程相互作用。在这项研究中，我们将采用第二代测序技术，调查环境因素是如何与种群结构和物种形成的进化在深海中，在中性和功能位点。特别重点将是生境深度和距离隔离，但其他环境因素将在收集地点量化的基础上收集的数据，从同一地点在最近的ECOMAR财团研究（在此期间，拟议的研究样本收集）。研究物种将是Coryphaenoides属的鱼类，这是一个似是而非的深海底层鱼类属，其中一些是重要的商业渔业物种（包括本研究的主要重点物种，C。岩生植物）。初步研究表明，系统发育谱系的划分与栖息地的深度有关。其他研究表明，在这些物种中，一些与适应压力有关的基因被选择。两个重点Coryphaenoides物种将在比较人口基因组学研究。这些物种，C. rupestris和C. brevibarbis是同域分布的，但前者比后者在较浅的深度发现。我们将测试假设栖息地划分的深度或其他特征（例如，当前的系统或地理距离）可能会决定内部和种间多样性的演变（包括在多个栖息地专家物种的属中使用扩展的系统发育评估）通过漂移（通过与扩散相关的不同环境压力）和选择。预计深海生境的连通性更大，这可能导致更大的有效种群规模，并促进适应性进化。这些数据将提供新的见解漂移和选择在多样性的演变过程中的相互作用，并可转移的多样性是如何在深海结构的推论。