Reconstructing an Ultrametric Galled Phylogenetic Network from a Distance Matrix

  • Ho-Leung Chan
  • Jesper Jansson
  • Tak-Wah Lam
  • Siu-Ming Yiu
Part of the Lecture Notes in Computer Science book series (LNCS, volume 3618)


Given a distance matrix M that specifies the pairwise evolutionary distances between n species, the phylogenetic tree reconstruction problem asks for an edge-weighted phylogenetic tree that satisfies M, if one exists. We study some extensions of this problem to rooted phylogenetic networks. Our main result is an O(n 2 log n)-time algorithm for determining whether there is an ultrametric galled network that satisfies M, and if so, constructing one. In fact, if such an ultrametric galled network exists, our algorithm is guaranteed to construct one containing the minimum possible number of nodes with more than one parent (hybrid nodes). We also prove that finding a largest possible submatrix M′ of M such that there exists an ultrametric galled network that satisfies M′ is NP-hard. Furthermore, we show that given an incomplete distance matrix (i.e., where some matrix entries are missing), it is also NP-hard to determine whether there exists an ultrametric galled network which satisfies it.


Distance Matrix Internal Node Evolutionary Path Tree Node Matrix Entry 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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Copyright information

© Springer-Verlag Berlin Heidelberg 2005

Authors and Affiliations

  • Ho-Leung Chan
    • 1
  • Jesper Jansson
    • 1
  • Tak-Wah Lam
    • 1
  • Siu-Ming Yiu
    • 1
  1. 1.Department of Computer ScienceThe University of Hong KongHong Kong

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