Decompositions of Multiple Breakpoint Graphs and Rapid Exact Solutions to the Median Problem

  • Authors:
  • Andrew Wei Xu;David Sankoff

  • Affiliations:
  • Department of Mathematics and Statistics, University of Ottawa, Canada K1N 6N5;Department of Mathematics and Statistics, University of Ottawa, Canada K1N 6N5

  • Venue:
  • WABI '08 Proceedings of the 8th international workshop on Algorithms in Bioinformatics
  • Year:
  • 2008

Quantified Score

Hi-index 0.00

Visualization

Abstract

The median genome problem reduces to a search for the vertex matching in the multiple breakpoint graph (MBG) that maximizes the number of alternating colour cycles formed with the matchings representing the given genomes. We describe a class of "adequate" subgraphs of MBGs that allow a decomposition of an MBG into smaller, more easily solved graphs. We enumerate all of these graphs up to a certain size and incorporate the search for them into an exhaustive algorithm for the median problem. This enables a dramatic speedup in most randomly generated instances with hundreds or even thousands of vertices, as long as the ratio of genome rearrangements to genome size is not too large.