Natural selection diversified CD94 and NKG2 residues in “lower” primates, but not in “higher” primates.

Maximum likelihood estimation of dN/dS ratios and detection of positively selected positions for the NKG2 and CD94 lectin-like domain sequences of ‘higher’ and ‘lower’ primates. The results of the likelihood ratio tests (see methods) are indicated on the left side of the panel and the positions detected as positively selected (with model M8) are listed on the right side of the panel (p>0.95; p>0.99 shown in bold). α, error level to reject the null model that does not allow for positive selection. NS, not significant. **, Bayesian analysis was not performed when the likelihood ratio tests were not significant. Residues in italics denote allelic substitutions were found at this site. Amino acid positions and numbering refer to human CD94 and NKG2A sequences and equivalent positions in aligned non-human primate sequences.