UPGMA and the normalized equidistant minimum evolution problem

Vincent Moulton, Andreas Spillner, Taoyang Wu

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3 Citations (Scopus)
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UPGMA (Unweighted Pair Group Method with Arithmetic Mean) is a widely used clustering method. Here we show that UPGMA is a greedy heuristic for the normalized equidistant minimum evolution (NEME) problem, that is, finding a rooted tree that minimizes the minimum evolution score relative to the dissimilarity matrix among all rooted trees with the same leaf-set in which all leaves have the same distance to the root. We prove that the NEME problem is NP-hard. In addition, we present some heuristic and approximation algorithms for solving the NEME problem, including a polynomial time algorithm that yields a binary, rooted tree whose NEME score is within O(log2n) of the optimum.
Original languageEnglish
Pages (from-to)1-15
Number of pages15
JournalTheoretical Computer Science
Early online date1 Feb 2018
Publication statusPublished - 18 Apr 2018


  • minimum evolution
  • balanced minimum evolution
  • hierarchical clustering

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