IS CONGRUENCE BETWEEN DATA PARTITIONS A RELIABLE PREDICTOR OF PHYLOGENETIC ACCURACY - EMPIRICALLY TESTING AN ITERATIVE PROCEDURE FOR CHOOSING AMONG PHYLOGENETIC METHODS

The relationship between phylogenetic accuracy and congruence between data partitions collected from the same taxa was explored for mitochon drial DNA sequences from two well-supported vertebrate phylogenies. An iterative procedure was adopted whereby accuracy, phylogenetic signal , and congruence were measured before and after modifying a simple rec onstruction model, Equally weighted parsimony. These modifications inc luded transversion parsimony successive weighting, and six-parameter p arsimony. For the data partitions examined, there is a generally posit ive relationship between congruence and phylogenetic accuracy. if cong ruence increased without decreasing resolution or phylogenetic signal this increased congruence was a good predictor of accuracy, If congrue nce increased as a result of poor resolution, the degree of congruence was not a good predictor of accuracy. For all sets of data partitions , six-parameter parsimony methods show a consistently positive relatio nship between congruence and accuracy. Unlike successive weighting, si x-parameter parsimony methods were not strongly influenced by the star ting tree.