Mechanisms of diversification in North American frogs

北美青蛙的多样化机制

• 批准号: 238462-2006
• 负责人: Lougheed, Stephen
• 金额: $ 2.26万
• 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: 2007
• 资助国家: 加拿大
• 起止时间: 2007-01-01 至 2008-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=361861
• 关键词: Mechanisms; diversification; North; American; frogs

Despite over six decades of research, a complete understanding of the mechanisms that generate species diversity remains elusive. Recently developed molecular tools and analytical methods afford us excellent opportunities to answer outstanding questions on the process of speciation. We address two of these using field and genetic studies of a small North American frog, the spring peeper. Our previous work identified major evolutionary lineages that have come into secondary contact in the northern portion of the species range after long periods of geographical isolation. For our first project, we will use a range of molecular and experimental approaches to test whether three pairs of divergent lineages now in secondary contact show evidence of reproductive isolation (a hallmark of speciation): reduction of ability to produce viable offspring, and divergence in male advertisement calls and female receptivity to them. Evidence of reproductive isolation will indicate that historical separation of populations may provide opportunity for divergence, but offers no insight as to its cause. Our second project will examine the proximate mechanisms that may cause such divergence. Specifically within an environmentally heterogeneous 4000 sq. km. area in Eastern Ontario, we will test whether selection pressures in habitats differing in vegetation structure and microclimate can produce significant differences in (1) spring emergence and calling by males, and (2) the acoustic properties of male advertisement calls. The combined insights from these projects will significantly advance our knowledge of the importance of, and interplay among, geographical isolation, contact zone dynamics, and ecological selection in diversification and speciation.

尽管经过了60多年的研究，对产生物种多样性的机制的完整理解仍然难以捉摸。最近发展的分子工具和分析方法为我们提供了很好的机会来回答关于物种形成过程的悬而未决的问题。我们通过对一种北美小青蛙春季窥视者的实地和基因研究来解决其中的两个问题。我们之前的工作确定了主要的进化谱系，这些谱系在经过长时间的地理隔离后，在物种范围的北部地区进行了二次接触。在我们的第一个项目中，我们将使用一系列分子和实验方法来测试目前处于二次接触中的三对不同谱系是否显示出生殖隔离（物种形成的标志）的证据：产生可存活后代的能力降低，以及雄性广告呼叫和雌性接受它们的差异。生殖隔离的证据将表明，种群的历史分离可能为分化提供了机会，但无法提供其原因的见解。我们的第二个项目将研究可能导致这种差异的近似机制。特别是在4000平方米的环境中。我们将测试在不同植被结构和小气候的生境中，选择压力是否会在(1)雄性的春季出现和鸣叫，以及(2)雄性广告叫声的声学特性上产生显著差异。这些项目的综合见解将大大提高我们对地理隔离、接触带动态和生态选择在多样化和物种形成中的重要性及其相互作用的认识。