Bioinformatics Advance Access first published online on January 18, 2008
This version published online on February 4, 2008
Bioinformatics, doi:10.1093/bioinformatics/btn024
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Inferring Horizontal Transfers in the Presence of Rearrangements by the Minimum Evolution Criterion
aSchool of Computer Science, Tel Aviv University, Tel Aviv, Israel.
bGoogle (work done while at the School of Computer Science and Communication, Royal Institute of Technology, Sweden).
*To whom correspondence should be addressed. Dr. Tamir Tuller, E-mail: tamirtul{at}post.tau.ac.i
| Abstract |
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Motivation: The evolution of viruses is very rapid and in addition to local point mutations (insertion, deletion, substitution) it also includes frequent recombinations, genome rearrangements, and horizontal transfer of genetic materials (HGTS) . Evolutionary analysis of viral sequences is therefore a complicated matter for two main reasons: First, due to HGTs and recombinations, the right model of evolution is a network and not a tree. Second, due to genome rearrangements, an alignment of the input sequences is not guaranteed. These facts encourage developing methods for inferring phylogenetic networks that do not require aligned sequences as input.
Results: In this work we present the first computational approach which deals with both genome earrangements and horizontal gene transfers and does not require a multiple alignment as input. We formalize a new set of computational problems which involve analyzing such complex models of evolution. We investigate their computational complexity, and devise algorithms for solving them. Moreover, we demonstrate the viability of our methods on several synthetic datasets as well as four biological datasets.
Availability: The code is available from the authors upon request.
Contact: tamirtul{at}post.tau.ac.i
Associate Editor: Prof. Keith Crandall
Received on June 7, 2007; revised on October 16, 2007; accepted on January 14, 2008