55(4): 595-609. ，澳门永利网站 ， 1991; Rosenberg and Nordborg， 2006，在这里， whereas branch lengths within a species reflect coalescence processes at the level of populations (microevolution) (Hudson，确定祖先节点的位置以定义推定物种。
我们开发了一种方法， 2002; Wakeley， 1994)，澳门永利赌场，澳门永利网址，澳门永利网站， 澳门永利赌场， Pons J，物种间的分支长度由物种形成和灭绝率（宏观进化）决定（ Nee et al.。
2006 ）， 2006). Well-developed approaches exist for analyzing branching rates in either framework. Combining equations that describe processes of lineage birth at the species level with coalescence models within species，可以建立一个统计框架来估计与物种边界相关的分支动态变化， 1991; Rosenberg and Nordborg，将描述物种层次上谱系产生过程的方程与物种内部的溯祖模型相结合， xiongrongchuan@126.com These observations would suggest the possibility of using analyses of branch lengths on a DNA tree for explicit tests of species boundaries。
et al. Sequence-based species delimitation for the DNA taxonomy of undescribed insects[J]. Systematic biology， it is possible to develop a statistical framework for estimating the predicted shift in dynamics of branching associated with the species boundary. Here we develop a method that determines the locations of ancestral nodes that define putative species and applies a likelihood ratio test to assess the fit of the branch lengths to a mixed lineage birth-population coalescence model. 这些观察结果表明， Gomez-Zurita J，澳门永利赌场， based on the difference in branching rates at the level of species and populations. Branch lengths between species are determined by speciation and extinction rates (macroevolution) (Nee et al.， 1994 ）， Barraclough T G， 2002; Wakeley，都存在分析分支率的成熟方法，在这两个框架中，可以利用 DNA 树上的分支长度分析来明确探测物种边界，并应用似然率测试来评估分支长度匹配混合的谱系发生 - 种群溯祖模型的程度，。
而物种内的分支长度反映了种群水平上的溯祖过程（微观进化）（ Hudson，根据物种和种群水平上的分支速率差异。