Slowly-evolving protein loci and higher-level snake phylogeny: A reanalysis

We reanalyzed data from a recently published study of higher-level snake re lationships based on four slowly-evolving protein loci. The original study used phenetic clustering of genetic similarities and presented a single, hi ghly resolved tree. Our reanalyses of these data reveal that the single pub lished phenogram is only one of at least 10,000 equivalent UPGMA phenograms , the consensus of which is largely unresolved. Additive distance analysis and character-based parsimony analysis of the data also yield little resolu tion, indicating that these data are highly ambiguous regarding higher-leve l snake phylogeny. The high degree of resolution in the published phenogram is an analytical artifact resulting from the failure to consider alternati ve trees implied by tied distance values, which are numerous in the distanc e matrix derived from this particular data set. Although the published phen ogram exhibits general agreement with traditional hypotheses about snake re lationships, the same appears to be true for the thousands of equivalent ph enograms, discrepancies among which sum to a substantial loss of resolution . Although the four loci sampled are evolving slowly relative to other comm only surveyed protein loci, they are nevertheless evolving too rapidly to b e informative about the higher level phylogeny of snakes.