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arXiv · 1805.00548

Quantifying the accuracy of ancestral state prediction in a phylogenetic tree under maximum parsimony

Lina Herbst·Thomas Li·Mike Steel
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Abstract

In phylogenetic studies, biologists often wish to estimate the ancestral discrete character state at an interior vertex $v$ of an evolutionary tree $T$ from the states that are observed at the leaves of the tree. A simple and fast estimation method --- maximum parsimony --- takes the ancestral state at $v$ to be any state that minimises the number of state changes in $T$ required to explain its evolution on $T$. In this paper, we investigate the reconstruction accuracy of this estimation method further, under a simple symmetric model of state change, and obtain a number of new results, both for 2-state characters, and $r$--state characters ($r>2$). Our results rely on establishing new identities and inequalities, based on a coupling argument that involves a simpler `coin toss' approach to ancestral state reconstruction.

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Lina Herbst, Thomas Li, Mike Steel. 2018-05-01. Quantifying the accuracy of ancestral state prediction in a phylogenetic tree under maximum parsimony. https://arxiv.org/abs/1805.00548

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