Imperial College London


Faculty of Natural SciencesDepartment of Mathematics

Visiting Professor



+44 (0)20 7594 2647c.colijn Website




626Huxley BuildingSouth Kensington Campus






BibTex format

author = {Colijn, C and Plazzotta, G},
doi = {sysbio/syx046},
journal = {Systematic Biology},
pages = {113--126},
title = {A metric on phylogenetic tree shapes},
url = {},
volume = {67},
year = {2017}

RIS format (EndNote, RefMan)

AB - The shapes of evolutionary trees are influenced by the nature of the evolutionary process but comparisons of trees from different processes are hindered by the challenge of completely describing tree shape. We present a full characterization of the shapes of rooted branching trees in a form that lends itself to natural tree comparisons. We use this characterization to define a metric, in the sense of a true distance function, on tree shapes. The metric distinguishes trees from random models known to produce different tree shapes. It separates trees derived from tropical versus USA influenza A sequences, which reflect the differing epidemiology of tropical and seasonal flu. We describe several metrics based on the same core characterization, and illustrate how to extend the metric to incorporate trees’ branch lengths or other features such as overall imbalance. Our approach allows us to construct addition and multiplication on trees, and to create a convex metric on tree shapes which formally allows computation of average tree shapes.
AU - Colijn,C
AU - Plazzotta,G
DO - sysbio/syx046
EP - 126
PY - 2017///
SN - 1076-836X
SP - 113
TI - A metric on phylogenetic tree shapes
T2 - Systematic Biology
UR -
UR -
VL - 67
ER -