Roles of isolation, secondary contact and gene flow in diversification and speciation.

隔离、二次接触和基因流在多样化和物种形成中的作用。

• 批准号: RGPIN-2014-06150
• 负责人: Lougheed, Stephen
• 金额: $ 3.06万
• 依托单位: Queen's University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2017
• 资助国家: 加拿大
• 起止时间: 2017-01-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=632010
• 关键词: Roles; isolation; secondary; contact; gene

One of the most enduring goals in evolutionary biology is to understand how new species arise. The traditional view, popularized by 20th Century evolutionary biologist Ernst Mayr, emphasized a geographic view of speciation where most new species arise or at least begin through physical and thus genetic isolation of ancestral populations. Recent theoretical and empirical work has moved away from these geography-based views of speciation to ones that emphasize mechanism (e.g. selection driving ecological divergence) producing important insights into how new species arise. However, our own NSERC-funded research over the last 5 years highlights the pervasiveness of both geographic isolation and subsequent secondary contact in the histories of most vertebrate species, mirroring comprehensive reviews of the phylogeographic literature. Thus, the long-term objective of my NSERC-funded research over the next 5 years is to quantify the role of such long-term geographical isolation, and consequences of range dynamics, and especially secondary contact in the evolution and maintenance of species.My proposed NSERC research focuses on a single temperate eastern North American frog, the spring peeper (Pseudacris crucifer), which I am developing into a model system for speciation studies. Our published work suggests that the spring peeper has a dynamic evolutionary history with 6 well-supported evolutionary lineages that originated in distinct, isolated refugia between 11 and 3 million years before present. Different lineage pairs with disparate times of divergence have come into secondary contact in different parts of the species’ range, presumably within the last 10-15,000 years. In the proposed research, my students and I will combine large-scale genomic and geographic information system (GIS) data, new statistical and modeling techniques, bioacoustical analysis, and playback and hybridization experiments to address a series of research questions on speciation: (i) What is the relation of divergence times between evolutionary lineages and patterns of reproductive isolation, the hallmark of biological species? (ii) What do genomic data say about the patterns of gene flow among lineages over the entire history of this species? (iii) Does secondary contact of closely-related lineages result in more effective reproductive barriers, either to diminish acoustic interference of male advertisement calls (used by females in mate choice), or to prevent maladaptive hybridization? (iv) How might marked differences in the acoustic environment or seasonality shape the outcomes of secondary contact between diverging lineages? (v) What are the various fitness costs of hybridization between lineages?My research program helps put Canada at the forefront of speciation research, bringing together perspectives from biogeography, genomics, landscape ecology, and ecological genetics. It provides important inputs into conservation strategies for Canadian species at risk, for example how best to retain evolutionary potential for future diversification and adaptation, and whether phylogeographic divisions merit separate conservation designation. The training program that I outline will provide premier opportunities for a minimum of 4 PhD, 3 MSc and 25 BSc students in genetics, quantitative methods, GIS, and professional development. As I have done in the past, I will leverage expertise developed with my NSERC research to seek additional funding and opportunities for applied landscape genetic & conservation studies of Canadian species at risk.

进化生物学中最持久的目标之一是了解新物种的出现。传统观点在20世纪进化生物学家恩斯特·梅尔（Ernst Mayr）受欢迎的情况下强调了对规范的地理看法，其中大多数新物种出现或至少是通过物理孤立的祖先人群开始的。最近的理论和经验工作已经从这些基于地理的规范观点转移到了强调机制（例如选择驱动生态差异）的规范观点，从而产生了对新物种的出现的重要见解。但是，在过去的5年中，我们自己由NSERC资助的研究突出了大多数脊椎动物历史上地理隔离和随后的次要接触的普遍性，这反映了对植物地理文献的全面评论。这是，在接下来的5年中，我由NSERC资助的研究的长期目标是量化这种长期地理隔离的作用，以及范围动态的后果，尤其是物种的演变和维持中的次要接触。我提出的NSERC研究重点是北美北美青蛙，Springer Peeler（Pseudacris crucifer）（PSEUDACRIS CRUCIFER），该模型是一个模型，该模型是一个模型。我们发表的工作表明，春皮具有动态的进化史，有6个良好支持的进化谱系，起源于在现场11到300万年之间的独特，孤立的避难所。可以预见的是，在过去10-15，000年内可以预见，在该物种范围的不同部位，不同的差异对差异时期已经进入了次要接触。在拟议的研究中，我和我的学生将结合大规模的基因组和地理信息系统（GIS）数据，新的统计和建模技术，生物声学分析以及播放和杂交实验，以解决有关规范的一系列研究问题：（i）差异和模式之间的差异和模式之间的差异是什么？ （ii）基因组数据在整个物种的整个史上谱系中基因流的模式怎么说？ （iii）与密切相关的谱系的次要接触会导致更有效的生殖屏障，以减少男性广告电话的声学干扰（女性在伴侣选择中使用），或者预防适应不良的杂交？ （iv）如何​​在声学环境或季节性中明显差异来塑造分歧谱系之间次级接触的结果？ （v）谱系之间的杂交成本是什么？我的研究计划有助于将加拿大置于规范研究的最前沿，从而将生物地理学，基因组学，景观生态学和生态遗传学的观点汇集在一起​​。它为有风险的加拿大物种提供了重要的投入，例如如何最好地保留未来多元化和适应的进化潜力，以及植物地理学划分是否值得单独的保护设计。我概述的培训计划将为至少4个博士学位，3个MSC和25位BSC学生提供遗传学，定量方法，GIS和专业发展的首要机会。正如我过去所做的那样，我将利用NSERC研究开发的专业知识，以寻求额外的资金和机会，以便对有风险的加拿大物种进行应用景观遗传和保护研究。