Jackknifing of weighted trees: validation of phylogenies reconstructed from distance matrices.

The jackknife strict consensus has been used to detect topological incompatibilities in phylogenetic trees derived from distance data. We here extend this approach to account for branch lengths, as well as topological relationships, when comparing jackknife pseudoreplicates. The average consensus procedure is used to derive a tree reflecting the agreement among the jackknife phylogenies. Combining the average tree with a minimum and a maximum consensus provides information about jackknife tree variability; the range consensus between the minimum and the maximum represents the topological agreement among them. We also demonstrate the effect of the number of pseudoreplicates on the resulting consensus trees by considering single and multiple deletions. The jackknife extensions that we propose are applied to both hypothetical and DNA-DNA hybridization distance data. Consideration of branch lengths reveals greater stability of the jackknife phylogeny than would be demonstrated by a strict consensus based on topology alone.