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arXiv 0803.2904q-bio.PEcs.CEcs.DM
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树-同胞时间一致系统进化网络的距离度量

A Distance Metric for Tree-Sibling Time Consistent Phylogenetic Networks

Gabriel Cardona, Merce Llabres, Francesc Rossello, Gabriel Valiente

摘要:

系统发育树中网状进化事件的存在使系统发育树系统发育树成为系统发育网络。这些事件意味着从一个非现存物种到一个现存物种可能存在多条进化路径,这种多样性使得系统发育网络的比较比系统发育树的比较要困难得多。事实上,迄今为止,所有试图在所有系统发育网络的类上定义声音距离度量的尝试都失败了。因此,唯一实际的解决方案是使用相似性的粗略估计(基于嵌入网络中的树的比较),或者将系统发育网络的类别缩小到这样的距离已知并且可以有效计算的特定类别。第一种方法的问题是,当两个网络不相等时,人们可能会将它们识别为等价网络;第二种方法的缺点是,可能不存在从生物序列重建这种网络的算法。本文提出了一类树兄弟时间一致性系统发育网络的距离度量,推广了树子时间一致性系统发育网络,从而也推广了Galled-tree。这种距离度量的实际意义是双重的:它可以通过简单的算法在多项式时间内计算,并且也存在从DNA序列数据重建此类网络的多项式时间算法。Perl包Bio::PhyloNetwork,包含在BioPerl包中,实现了许多关于系统发生网络的算法,包括本文中提出的距离计算。

英文摘要:

The presence of reticulate evolutionary events in phylogenies turn phylogenetic trees into phylogenetic networks. These events imply in particular that there may exist multiple evolutionary paths from a non-extant species to an extant one, and this multiplicity makes the comparison of phylogenetic networks much more difficult than the comparison of phylogenetic trees. In fact, all attempts to define a sound distance measure on the class of all phylogenetic networks have failed so far. Thus, the only practical solutions have been either the use of rough estimates of similarity (based on comparison of the trees embedded in the networks), or narrowing the class of phylogenetic networks to a certain class where such a distance is known and can be efficiently computed. The first approach has the problem that one may identify two networks as equivalent, when they are not; the second one has the drawback that there may not exist algorithms to reconstruct such networks from biological sequences. We present in this paper a distance measure on the class of tree-sibling time consistent phylogenetic networks, which generalize tree-child time consistent phylogenetic networks, and thus also galled-trees. The practical interest of this distance measure is twofold: it can be computed in polynomial time by means of simple algorithms, and there also exist polynomial-time algorithms for reconstructing networks of this class from DNA sequence data. The Perl package Bio::PhyloNetwork, included in the BioPerl bundle, implements many algorithms on phylogenetic networks, including the computation of the distance presented in this paper.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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