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arXiv 1012.5165q-bio.PEq-bio.QM
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系统发育树和网络上一般Markov模型的代数

The algebra of the general Markov model on phylogenetic trees and networks

J. G. Sumner, B. H. Holland, P. D. Jarvis

摘要:

已知在系统发育树上的序列进化的Kimura 3ST模型可以相当自然地扩展到任意分裂系统。然而,这种扩展在很大程度上依赖于K3ST模型的数学特性,并且迄今为止还难以提供一般马尔可夫模型的类似增强。在本文中,我们纠正这一缺点,展示了如何扩展一般马尔可夫模型的树,包括任意分裂,甚至进一步更一般的网络模型。这是通过探索连续时间马尔可夫链的生成器的代数以及在系统发育树上生成分支过程的"分裂"算子来实现的。为了简单起见,我们继续讨论两个状态的情况下,并注意到,我们的结果很容易扩展到更多的状态,几乎没有复杂性。有趣的是,在限制的两个状态一般马尔可夫模型的参数空间的二进制对称模型,我们的扩展是无法区分的,从以前的方法,只有在树上,只要任何不兼容的分裂引入这两种方法产生不同的概率分布与不同的结构。通过探索一个简单的例子,我们给出了一个试探性的论点,我们的方法扩展到更一般的网络具有理想的属性,以前的方法不共享。特别是,我们的构建允许先前不同谱系的趋同进化的可能性;这一特性对生物学应用具有重要意义。

英文摘要:

It is known that the Kimura 3ST model of sequence evolution on phylogenetic trees can be extended quite naturally to arbitrary split systems. However, this extension relies heavily on mathematical peculiarities of the K3ST model, and providing an analogous augmentation of the general Markov model has thus far been elusive. In this paper we rectify this shortcoming by showing how to extend the general Markov model on trees to to include arbitrary splits; and even further to more general network models. This is achieved by exploring the algebra of the generators of the continuous-time Markov chain together with the "splitting" operator that generates the branching process on phylogenetic trees. For simplicity we proceed by discussing the two state case and note that our results are easily extended to more states with little complication. Intriguingly, upon restriction of the two state general Markov model to the parameter space of the binary symmetric model, our extension is indistinguishable from the previous approach only on trees; as soon as any incompatible splits are introduced the two approaches give rise to differing probability distributions with disparate structure. Through exploration of a simple example, we give a tentative argument that our approach to extending to more general networks has desirable properties that the previous approaches do not share. In particular, our construction allows for the possibility of convergent evolution of previously divergent lineages; a property that is of significant interest for biological applications.

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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