RSV phylogenic tree. Alignment of G protein sequences (from aa 212 to the end) was undertaken with Clustal 2.0 software. Sequences were aligned with 9 reference sequences of the subgroup A, including 7 genotypes and the A2 and Long strains. Subgroup B was represented by sequences representative of 5 genotypes. The phylogenic tree was designed using the maximum parsimony algorithm and was drawn with Mega 4.0 software using PHYLIP method. The tree was rooted between subgroups A and B.