Rooted phylogenetic tree calculated for groEL sequences of Sii CJ18 and related streptococci. Rooted phylogenetic tree was calculated for the groEL genes of Sii CJ18, related SBSEC members and other streptococci. CJ18 was clearly positioned on the same branch as Sii ATCC BAA-102T within the SBSEC. The same phylogenetic position of CJ18 was obtained for the 16S rRNA gene and gyrB, recA, recN, rpoB, secA, secY and sodA with groEL, secY and recN yielding highest bootstrap percentages (data not shown). The evolutionary distances indicated by the horizontal bar below the figure are in the units of the number of base substitutions per site.