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Ecological genetics of local adaptation: Climatic races in Arabidopsis thaliana and Arabis fecunda.

机译：局部适应的生态遗传学：拟南芥和拟南芥的气候种族。

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摘要

Local adaptation, or the presence of genetically based trait differences among populations that result from natural selection, appears to be quite common in plant species. However, any two independent populations may diverge in phenotypes, even in the absence of differential selective pressures. The degree of population divergence that results from natural selection is therefore of fundamental interest to evolution as well as the applied sub-discipline of conservation genetics. In chapter 1 I review a body of theory which develops an expectation of both marker and trait divergence in the absence of natural selection. Based on this theory and data from 29 species I compare expected divergence at neutral markers and neutral quantitative traits. Results show that quantitative trait divergence among populations is greater than expected from neutral divergence, providing support for the ubiquity of local adaptation. Chapter 2 describes a case study of Arabis fecunda populations at high and low elevation sites that differ in water availability. Common garden screenings show that several specific quantitative traits likely to be important for drought adaptation have diverged among populations, despite a general lack variation or structure at neutral markers.; Ultimately, evolutionary constraints and the rate of adaptive evolution will depend on the genetic basis of adaptive traits. Drought (water availability) is thought to be one of the major climatic factors to which populations locally adapt, and a number of traits have been identified which may contribute to drought adaptation. Understanding the genetic basis of drought tolerance is an important goal in both ecology and agriculture, and provides an ideal framework to understand potential genetic constraints and correlated responses. In chapter 3 I examine natural variation in drought tolerance traits in Arabidopsis thaliana, a model system whose genome has been completely sequenced. A screening of natural accessions reveals a large positive genetic correlation between drought tolerance and time to flowering. I demonstrate that allelic variation at gene for flowering time (Frigida) is also responsible for variation in physiological and drought tolerance traits, suggesting that natural selection has caused the fixation of a pleiotropic gene.
机译：在植物物种中，局部适应或自然选择导致的种群间基于遗传的性状差异似乎很普遍。但是，即使没有差异的选择性压力，任何两个独立的种群也可能在表型上有所差异。因此，自然选择引起的种群分化程度对于进化以及保护遗传学的应用子学科都至关重要。在第一章中，我回顾了一个理论体系，该理论在缺乏自然选择的情况下对标记和性状差异都有了期望。基于这一理论和来自29个物种的数据，我比较了中性标记和中性定量性状的预期差异。结果表明，种群之间的数量性状差异比中性差异要大，这为局部适应的普遍性提供了支持。第2章介绍了一个案例研究，该案例是在高水位和低水位的不同水域下的拟南芥种群。常见的花园筛选显示，尽管在中性标记处普遍缺乏变异或结构，但种群之间仍存在着一些可能对干旱适应重要的特定数量性状。最终，进化限制和适应性进化的速度将取决于适应性状的遗传基础。干旱（水的可用性）被认为是当地人口适应的主要气候因素之一，并且已经确定了许多可能有助于干旱适应的特征。理解耐旱性的遗传基础是生态和农业领域的重要目标，并且为了解潜在的遗传限制和相关响应提供了理想的框架。在第三章中，我研究了拟南芥（Arabidopsis thaliana）的耐旱性状的自然变异，拟南芥是一个基因组已完全测序的模型系统。对天然种质的筛选显示出耐旱性和开花时间之间存在很大的正相关性。我证明了开花时间的基因（Frigida）的等位基因变异也是生理和干旱耐受性状变异的原因，这表明自然选择已引起多效性基因的固定。

著录项

  • 作者

    McKay, John Keith.;

  • 作者单位

    University of Montana.;

  • 授予单位 University of Montana.;
  • 学科 Biology Genetics.; Biology Ecology.; Biology Plant Physiology.
  • 学位 Ph.D.
  • 年度 2001
  • 页码 119 p.
  • 总页数 119
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 遗传学;生态学（生物生态学）;植物学;
  • 关键词

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