Cardona Gabriel, Rosselló Francesc, Valiente Gabriel
Department of Mathematics and Computer Science, University of the Balearic Islands, E-07122 Palma de Mallorca, Spain.
Math Biosci. 2008 Feb;211(2):356-70. doi: 10.1016/j.mbs.2007.11.003. Epub 2007 Dec 3.
Phylogenetic networks are a generalization of phylogenetic trees that allow for the representation of non-treelike evolutionary events, like recombination, hybridization, or lateral gene transfer. In a recent series of papers devoted to the study of reconstructibility of phylogenetic networks, Moret, Nakhleh, Warnow and collaborators introduced the so-called tripartition metric for phylogenetic networks. In this paper we show that, in fact, this tripartition metric does not satisfy the separation axiom of distances (zero distance means isomorphism, or, in a more relaxed version, zero distance means indistinguishability in some specific sense) in any of the subclasses of phylogenetic networks where it is claimed to do so. We also present a subclass of phylogenetic networks whose members can be singled out by means of their sets of tripartitions (or even clusters), and hence where the latter can be used to define a meaningful metric.
系统发育网络是系统发育树的一种推广，它允许表示非树状的进化事件，如重组、杂交或横向基因转移。在最近一系列致力于研究系统发育网络可重构性的论文中，莫雷特、纳赫莱、瓦尔诺及其合作者引入了所谓的系统发育网络的三分度量。在本文中，我们表明，事实上，在声称该三分度量满足距离分离公理（零距离意味着同构，或者在更宽松的版本中，零距离意味着在某种特定意义上不可区分）的任何系统发育网络子类中，它都不满足该公理。我们还提出了系统发育网络的一个子类，其成员可以通过它们的三分集（甚至聚类）来区分，因此在该子类中，后者可用于定义一个有意义的度量。
