Computing the Quartet Distance Between Trees of Arbitrary Degree

Abstract. We present two algorithms for computing the quartet distance between trees of arbitrary degree. The quartet distance between two unrooted evolutionary trees is the number of quartets—sub-trees induced by four leaves—that differs between the trees. Previous algorithms focus on computing the quartet distance between binary trees. In this paper, we present two algorithms for computing the quartet distance between trees of arbitrary degrees. One in time O(n3 ) and space O(n2 ) and one in time O(n2 d2 ) and space O(n2 ), where n is the number of species and d is the maximal degree of the internal nodes of the trees. We experimentally compare the two algorithms and discuss possible directions for improving the running time further.

• Type: Conference
• Year: 2005
• Where: WABI
• Authors: Chris Christiansen, Thomas Mailund, Christian N. S. Pedersen, Martin Randers
• Keywords: Algorithms, Arbitrary Degrees, Quartet Distance, WABI 2005