Fig. 7

Adaptive evolution of PSGs in Yangochiroptera bat species. a For the detection of individual sites under positive selection (red letters) we used MEME software after screening for recombination using GARD software. All PSGs from M. lucifugus were used for the analysis. The amino acid sequences encoded by the M. lucifugus PSG1 N domain exon is shown with the positively selected amino acids marked in red. b Identification of N domain-wide episodic selection. A branch-site unrestricted statistical test for episodic diversification (BUSTED) approach was used for the identification. c The accumulation of non-synonymous (green curves) and synonymous substitutions (red curves) along the N exons of PSGs. The blue curve indicates insertions or deletions of nucleotides. Note preferential accumulation of nonsynonymous mutations in the CC’C″FG β-strand regions (black broken lines) which indicates selection for diversification. This contrasts with a conserved region between CC’C″ and FG β-strands indicated by a red broken line. The location of CC’C″ and FG β-strand regions was determined by 3D modeling (d) Three-dimensional modeling (Geno3D) of the N domain of PSG1 from M. lucifugus. In the left ribbon model the CC’C″FG β-strands are indicated by an arrow. The right model is horizontally rotated by 90° clockwise. Positively selected sides are shown in green. Note that multiple positively selected sides are located in the CFG face which is known to interact homo- and heterotypically in other CEACAMs