Evolution of some variable-number tandem repeat loci among a group of Beijing strains of Mycobacterium tuberculosis

SummaryThe patterns of variable-number tandem repeats (VNTR) genotypes of a clonal group of Mycobacterium tuberculosis Beijing isolates with very similar IS6110-restriction fragment length polymorphism (RFLP) patterns were studied. Differences between VNTR were mostly by a single repeat unit. However, a multiple-unit change also occurred. This suggests that a mechanism other than the slipped-strand mispairing might be responsible for the instability of VNTR in M. tuberculosis as well. This finding is useful for inferring phylogenetics of M. tuberculosis based on the VNTR genotypes.