Fig. 8

Regions of positive selection differ between PSGs and CEACAMs. a Sites within N domain exons (x-axis) with episodic diversifying selection as detected by MEME were plotted (red bars) against the p value (level of significance; y-axis). Genes used for the analyses are indicated. Note that in CEACAMs, PSGs group I and PSGs group II different sides are under positive selection. b, c, d Selection at defined sites of PSGs of group I from M. lucifugus. The position of the analyzed amino acid (AA) is indicated on top of the phylogenetic tree. Phylogenetic trees of group I PSGs are shown. Red lines indicate positive selection, black lines neutral selection and blue lines negative selection. Note that at several nodes one arm is under positive selection while the second is under neutral or negative selection. The number of PSGs of which a certain amino acid is under positive selection varies between individual positions. Scale bar at the top indicates substitutions per site