Ratio of explanatory power (REP): A new measure of group support

摘要

Bremer support (BS; [Bremer, 1988] and [K?llersj? et al., 1992]) is frequently employed as a measure of group support in parsimony-based phylogenetic analysis. For a given group present in the most-parsimonious tree, Bremer support is defined asS′-S, where S denotes the length of the most-parsimonious tree (Kluge and Farris, 1969) and S′ is the length of the most-parsimonious tree that lacks that group. In other words, BS measures the difference in the explanatory power of the two hypotheses (Kluge and Grant, 2007), and is therefore a measure of objective support (Grant and Kluge, 2003). (For simplicity, we refer only to comparisons of pairs of hypotheses, but the same arguments also apply when sets of optimal hypotheses are compared to sets of equally suboptimal hypotheses.)