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 targeted organism prior to DNA extraction is often not necessary. This approach has been successfully utilized to detect various organisms including Mtb [Brisson-Noel et al. 1989; Wren et al. 1990; Eisenach et al. 1991]. (4)

Restriction Fragment Length Polymorphic (RFLP) Analysis RFLP is widely utilized to distinguish genetic changes within a species. A pure clone of each of the organisms of interest must be generated using standard culturing techniques. The genomic DNA is isolated and cut with a series of restriction enzymes. Each of these enzymes cut double-stranded DNA at a unique, short sequence of DNA bases, generating genomic DNA fragments of various sizes [Sambrook et al. 1989]. The DNA fragments are examined by sizing them on agarose gels. Eventually, the region(s) of altered DNA is detected. The fragment appears as a different size when compared to the other isolates. Confirmation may be accomplished by using gene probes as described above.

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