KemenyYoungmetoden

The Kemeny-Youngmetoden, commonly referred to as the Kemeny–Young method, is a phylogenetic inference approach designed to reconstruct evolutionary trees from character data by optimizing a global agreement with the observed information. It is part of the family of methods that seek a single tree which best represents multiple sources of evidence rather than relying on stepwise criteria.

In essence, the method assigns weights to structural features of trees, such as splits or quartet topologies, based on the input data. The score of a candidate tree is the sum of weights of the features that the tree makes compatible with the data. The Kemeny-Youngmetoden then selects the tree with the maximum total weight, aiming to maximize overall concordance between the data and the inferred topology.

Computationally, the problem is difficult. Finding the exact maximum-weight tree is typically NP-hard for standard formulations, which means exact solutions are practical only for smaller datasets or when aided by specialized algorithms and significant computing resources. For larger applications, heuristic or approximate strategies are commonly employed to obtain near-optimal trees.

Historically, the method is named after references in the field to Kemeny and Young, who contributed to distance- and consensus-based approaches in discrete mathematics and their application to phylogenetics. In practice, the Kemeny-Youngmetoden is less widely used today compared with likelihood- or Bayesian-based methods, or with quartet-based maximum compatibility approaches. Nevertheless, it remains of methodological interest as an exact or near-exact optimization framework for tree reconstruction and as a conceptual benchmark for evaluating concordance-based phylogenetic strategies.

See also: phylogenetic tree, maximum compatibility, quartet methods, consensus methods, split systems.