Unique replacement sites and results of branch-site analyses of positive selection for mitochondrial protein-coding genes early in snake evolution.

The number of sites per gene inferred as being under positive selection based on branch-site model analyses in PAML are shown at two posterior probability (PP) significance levels. The branch-site model of positive selection was tested for two main snake lineages: the lineage leading to all snakes (��Snake Branch��) and the lineage leading to the Alethinophidia (��Alethinophidia Branch��); relative support for selection at sites is based on posterior probability (PP) support from Bayes empirical Bayes estimates in PAML. Note: in this table, ��sites�� refer to amino acid sites.