DISTRIBUTIONS OF TREE COMPARISON METRICS - SOME NEW RESULTS
DISTRIBUTIONS OF TREE COMPARISON METRICS - SOME NEW RESULTS
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DOI：
10.2307/2992536
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发表时间：
1993-06-01
影响因子：
6.5
通讯作者：
PENNY, D
中科院分区：
文献类型：
--
作者：
STEEL, MA;PENNY, D
用于比较树的相异性度量（metrics）是进化树定量分析的重要工具，但它们的许多性质并不完全清楚。本文件报告公式的分布三类树比较度量：分区（或对称差）度量，四重度量（比较子集的四个类群），和度量的基础上对类群之间的路径长度差异。研究的属性包括树木的几个基本分布的均值和方差、范围、类群数量的影响和计算方法。本文给出了三个基本定理及其证明，每一类树比较度量各有一个。划分度量生成一个渐近泊松分布的大多数分布的树（其平均值是三个树分布）。精确的表达式推导出的四重度量的方差和度量的均方值的基础上的路径差异。影响用于特定研究的度量的选择的因素包括被比较的树的相似程度和被测试的假设的类型（例如，这些树是否估计相同的潜在遗传或仅仅以某种可能未知的方式相关）。
Measures of dissimilarity (metrics) for comparing trees are important tools in the quantitative analysis of evolutionary trees, but many of their properties are incompletely known. The present paper reports formulae for the distributions of three classes of tree comparison metrics: the partition (or symmetric difference) metric, the quartet metric (which compares subsets of four taxa), and a metric based on path-length differences between pairs of taxa. The properties studied include the mean and variance for several underlying distributions of trees, the range, the effect of the number of taxa, and methods of calculation. Three basic theorems and their proofs are reported, one for each class of tree comparison metric. The partition metric generates an asymptotic Poisson distribution for most distributions of trees (its mean is given for three tree distributions). Exact expressions are derived for the variance of the quartet metric and the mean square value of a metric based on path differences. Factors that affect the choice of a metric for a particular study include the degree of similarity of the trees being compared and the type of hypothesis being tested (e.g., whether the trees estimate the same underlying phylogeny or are simply related in some, perhaps unknown, way).