Fig. 2.

Molecular phylogeny of choanoflagellates based on a concatenated four-gene dataset. The tree shown was derived by Bayesian inference based on a combined tubA, hsp90, SSU, and LSU rDNA nucleotide sequence alignment. Branches are drawn proportional to the number of nucleotide substitutions per site as indicated by the scale bar at the lower left. Branches receiving 1.00 biPP and 100% mlBP support are denoted by an *. biPP and mlBP values are otherwise given above and below branches respectively. Additional values are shown for four important deep branches in the choanoflagellate and Metazoa grouping, indicating support values obtained when the unstable, long-branched taxa Corallochytrium limacisporum and Nuclearia simplex were excluded.