Evolutionary Relationships among Strains of Mycobacterium tuberculosis with Few Copies of IS 6110

Abstract
Molecular typing of Mycobacterium tuberculosis by using IS 6110 shows low discrimination when there are fewer than five copies of the insertion sequence. Using a collection of such isolates from a study of the epidemiology of tuberculosis in London, we have shown a substantial degree of congruence between IS 6110 patterns and both spoligotype and PGRS type. This indicates that the IS 6110 types mainly represent distinct families of strains rather than arising through the convergent insertion of IS 6110 into favored positions. This is supported by identification of the genomic sites of the insertion of IS 6110 in these strains. The combined data enable identification of the putative evolutionary relationships of these strains, comprising three lineages broadly associated with patients born in South Asia (India and Pakistan), Africa, and Europe, respectively. These lineages appear to be quite distinct from M. tuberculosis isolates with multiple copies of IS 6110 .

This publication has 73 references indexed in Scilit: