Figure 2

The evolutionaty tree of the the polyamine oxidase proteins. The evolutionary history tree of the SMO, PAO, and APAO polyamine oxidase proteins in Metazoa as inferred by using the Maximum Likelihood method based on the JTT model with a proportion of invariable sites (I) and gamma-distributed rates across sites (G) (Bayesian tree showed identical topology at the main nodes; data not shown). The analysis involved 76 amino acidic sequences with the yeast sequence used as outgroup. In correspondence of the main nodes (black circles) the bootstrap support (BS) and Bayesian posterior probabilities (BPP) values are reported (above: BS; below: BPP). The support for the secondary nodes is reported as white circles (BS = 100; BPP = 1.00) and grey circles (BS ranging from 90 to 99; BPP = 1.00). The tree is drawn to scale, with branch lengths measured in the number of substitutions per site. Main monophyletic groups are indicated as follow: M = mammals; B = birds; R = reptiles; A = amphibians; F = fishes; I = insects.