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arXiv 1607.06285q-bio.PEcs.DS
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分支长度有助于在系统发育网络中定位一棵树吗?

Do branch lengths help to locate a tree in a phylogenetic network?

Philippe Gambette, Leo van Iersel, Steven Kelk, Fabio Pardi, Celine Scornavacca

摘要:

系统发生网络越来越多地用于进化生物学,以代表物种的历史,经历了网状事件,如水平基因转移,杂交物种形成和重组。在这种背景下出现的最基本的问题之一是,是否可以通过给定的网络来解释所有物种中具有一个拷贝的基因的进化。在数学术语中,这通常被翻译成以下方式:给定的系统发育树是否包含在给定的系统发育网络中?最近,这种树包含问题已经从计算的角度被广泛地研究,但是大多数研究仅仅集中在系统发育的拓扑结构上,忽略了一条信息,在系统发育树的情况下,通常通过进化分析推断:分支长度。这些测量变化的量(例如,核苷酸取代),其沿着同源性的每个分支发生。在这里,我们研究了一些版本的树包含问题,明确占分支长度。我们表明,虽然长度信息有可能更精确地定位一棵树在网络中,这个问题是在其最一般的形式计算困难。积极的一面是,对于一些生物相关性的特殊情况,我们提供了有效解决这个问题的算法。这包括有限复杂度的网络的情况,对于这种情况,可以在具有与输入树相同拓扑的网络所包含的树中恢复在分支长度方面最接近的一个。

英文摘要:

Phylogenetic networks are increasingly used in evolutionary biology to represent the history of species that have undergone reticulate events such as horizontal gene transfer, hybrid speciation and recombination. One of the most fundamental questions that arise in this context is whether the evolution of a gene with one copy in all species can be explained by a given network. In mathematical terms, this is often translated in the following way: is a given phylogenetic tree contained in a given phylogenetic network? Recently this tree containment problem has been widely investigated from a computational perspective, but most studies have only focused on the topology of the phylo- genies, ignoring a piece of information that, in the case of phylogenetic trees, is routinely inferred by evolutionary analyses: branch lengths. These measure the amount of change (e.g., nucleotide substitutions) that has occurred along each branch of the phylogeny. Here, we study a number of versions of the tree containment problem that explicitly account for branch lengths. We show that, although length information has the potential to locate more precisely a tree within a network, the problem is computationally hard in its most general form. On a positive note, for a number of special cases of biological relevance, we provide algorithms that solve this problem efficiently. This includes the case of networks of limited complexity, for which it is possible to recover, among the trees contained by the network with the same topology as the input tree, the closest one in terms of branch lengths.

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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