Title
Approximation Algorithms for Nonbinary Agreement Forests.
Abstract
Given two rooted phylogenetic trees on the same set of taxa X, the Maximum Agreement Forest (MAF) problem asks to find a forest that is, in a certain sense, common to both trees and has a minimum number of components. The Maximum Acyclic Agreement Forest (MAAF) problem has the additional restriction that the components of the forest cannot have conflicting ancestral relations in the input trees. There has been considerable interest in the special cases of these problems in which the input trees are required to be binary. However, in practice, phylogenetic trees are rarely binary, due to uncertainty about the precise order of speciation events. Here, we show that the general, nonbinary version of MAF has a polynomial-time 4-approximation and a fixed-parameter tractable (exact) algorithm that runs in O(4(k)poly(n)) time, where n = vertical bar X vertical bar and k is the number of components of the agreement forest minus one. Moreover, we show that a c-approximation algorithm for nonbinary MAF and a d-approximation algorithm for the classical problem Directed Feedback Vertex Set (DFVS) can be combined to yield a d(c+3)-approximation for nonbinary MAAF. The algorithms for MAF have been implemented and made publicly available.
Year
DOI
Venue
2014
10.1137/120903567
SIAM JOURNAL ON DISCRETE MATHEMATICS
Keywords
DocType
Volume
phylogenetic tree,agreement forests,approximation algorithm,fixed-parameter tractability,phylogenetic network
Journal
28
Issue
ISSN
Citations 
1
0895-4801
3
PageRank 
References 
Authors
0.45
0
4
Name
Order
Citations
PageRank
Leo van Iersel121524.58
Steven Kelk219325.60
Nela Lekic3244.19
Leen Stougie4892107.93