PHYLOGENETICALLY NESTED COMPARISONS FOR TESTING CORRELATES OF SPECIES RICHNESS: A SIMULATION STUDY OF CONTINUOUS VARIABLES
PHYLOGENETICALLY NESTED COMPARISONS FOR TESTING CORRELATES OF SPECIES RICHNESS: A SIMULATION STUDY OF CONTINUOUS VARIABLES
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用于测试物种丰富度相关性的系统发育嵌套比较：连续变量的模拟研究
DOI：
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发表时间：
2003
期刊：
影响因子：
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通讯作者：
A. Purvis
中科院分区：
文献类型：
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作者：
N. Isaac;P. Agapow;P. Harvey;A. Purvis
摘要 解释物种在谱系中的不均匀分布是进化中最古老的问题之一。生物性状和物种多样性之间的拟议相关性通常通过系统发育姐妹进化枝之间的比较来测试。最近的几项研究使用嵌套姐妹进化枝比较来检验将不断变化的特征（例如体型）与多样性联系起来的假设。评估这些研究的结果很复杂，因为它们在使用的物种丰富度差异指数、处理性状差异的方式以及采用的统计检验方面有所不同。在本文中，我们使用模拟来比较四种物种丰富度指数、用于估计内部节点性状值的分支长度的两种选择以及在一系列进化枝生长和性状进化模型下的两种统计测试的性能。当满足方法的假设并且分支长度设置为与时间成比例时，所有四个指数都返回适当的 I 类错误率。只有两个指数对于不同的进化模型以及分支长度和统计检验的不同选择是稳健的。这些稳健的指数在一种非零情景下具有相当的功效。通过原点的回归始终比 t 检验更有效，并且分支长度的选择对有效性和功效都有很大影响。根据我们的模拟，我们重新评估了那些以前在物种丰富度背景下使用嵌套比较的人的发现。我们提供了一套简单的指南，以最大限度地提高物种丰富度的推定相关性测试中系统发育嵌套比较的性能。
Abstract Explaining the uneven distribution of species among lineages is one of the oldest questions in evolution. Proposed correlations between biological traits and species diversity are routinely tested by making comparisons between phylogenetic sister clades. Several recent studies have used nested sister-clade comparisons to test hypotheses linking continuously varying traits, such as body size, with diversity. Evaluating the findings of these studies is complicated because they differ in the index of species richness difference used, the way in which trait differences were treated, and the statistical tests employed. In this paper, we use simulations to compare the performance of four species richness indices, two choices about the branch lengths used to estimate trait values for internal nodes and two statistical tests under a range of models of clade growth and character evolution. All four indices returned appropriate Type I error rates when the assumptions of the method were met and when branch lengths were set proportional to time. Only two of the indices were robust to the different evolutionary models and to different choices of branch lengths and statistical tests. These robust indices had comparable power under one nonnull scenario. Regression through the origin was consistently more powerful than the t-test, and the choice of branch lengths exerts a strong effect on both the validity and power. In the light of our simulations, we re-evaluate the findings of those who have previously used nested comparisons in the context of species richness. We provide a set of simple guidelines to maximize the performance of phylogenetically nested comparisons in tests of putative correlates of species richness.