Fig. 2.

Molecular phylogenetic tree of MHC class I B sequences reconstructed using the maximum likelihood method based on the Tamura 3-parameter model. The model used a discrete gamma distribution allowing evolutionary rate differences among sites. The tree with the highest log likelihood (−7151.1817) is shown. Confidence in the branching patterns is indicated by bootstrap values and only relevant values (≥50) are shown. The scale indicates the number of substitutions per site. The tree was rooted with an outgroup consisting of the indicated MHC-A sequences. The three species humans, chimpanzees, and bonobos are represented by circles, triangles, and squares, respectively, in front of the sequence names