Evolutionary tree that describes the hypothetical
emergence of H. pylori type I as a result of an event of
gene conversion (PAI acquisition). Presumably, it is only after the
integration of an IS605 that subpopulations of
intermediate strains with attenuated virulence are differentiated.
cag retention is indicated by arrows. Type II strains
are distinguishable from type I strains with a complete
cag deletion by the absence of IS605. The
following strains have the genotypes listed in the tree. Genotypes:
1, G11, G33, G46, G89, G103, G109, 932, Ba99, Ba 137, and
Ba158; 2, CCUG 17874, G32, G56, G106, and G204;
3, 60190, G20, G27, G29, G65, Ba179, and Ba 211;
4, G39, D933, Ba167, Ba182, Ba194, and Ba212; 5,
G12 and G25; 6, G104 and D925; 7, Tx30a and G50;
8, Ba82, Ba142, G21, G198, 2U+, and 2U-.