Amplified rDNA (Ribosomal DNA) Restriction Analysis is the extension of the technique of RFLP (restriction fragment length polymorphism) to the gene encoding the small (16s) ribosomal subunit of bacteria. The technique involves an enzymatic amplification using primers directed at the conserved regions at the ends of the 16s gene, followed by digestion using tetracutter Restriction enzymes. The pattern obtained is said to be representative of the species analysed. Patterns obtained from several restriction enzymes can be used to phylogenetically characterize cultured isolates and 16s genes obtained through cloning from community DNA