Insertion element IS6110-based restriction fragment length polymorphism genotyping of Mycobacterium tuberculosis

DNA fingerprinting techniques are based on genome variation and form the basis of molecular epidemiology studies of tuberculosis. A number of markers are in use for the molecular differentiation of Mycobacterium tuberculosis isolates by DNA fingerprinting. One of these markers is the IS6110 insertion element, which may be present in up to 25 copies per M. tuberculosis genome. Variation in both the number and location of the IS6110 elements makes it a very useful marker of strain genotype. IS6110-based DNA fingerprinting is globally considered as the reference genotyping technique for M. tuberculosis isolates. This method is based on visualization of restriction fragment length polymorphisms using a labeled probe derived from IS6110. In this chapter, the method of IS6110 DNA fingerprinting is explained in such a way that it can be easily duplicated by molecular epidemiologists and will give reproducible results.