Positive selection acting on orthologs. Map of the amino acids involved in the binding of ligand  on the SAL1 3D structure are in blue, and positively selected sites in pink (PDB: 1GM6). Amino acids shown in a van der Waals representation (orange) were both involved in ligand binding and were positively selected. Positively selected amino acids were identified by PAML computations using site models.
Meslin et al. BMC Evolutionary Biology 2011 11:148 doi:10.1186/1471-2148-11-148