Ribotyping is a technique for bacterial identification that employs some of the methods previously discussed for ribosomal RNA Based phylogenetic characterizations. However, unlike comparative sequencing methods, ribotyping does not involve sequencing. Instead it measures the unique pattern that is generated when DNA from an organism is digested by a restriction enzyme & the fragments are separated & probed with a ribosomal RNA prob.
Because differences in ribosomal RNA sequence between two organisms translate in to the presence or absence of specific restriction enzymes. At sites the restriction pattern of a particular bacterial species unique. In fact ribotyping is so specific; it has been given the nickname â€œMolecular Finger printingâ€ because a unique series of bands appears for virtually any organism.
In practice ribotyping starts with DNA from a colony or liquid culture 0.6 0.4 0.2 0. inkage distance
Using PCR, gones for 16sr RNA and related molecules are amplified, treated with one or more restriction enzymes, separated by electrophoresis, and then probed.
The pattern generated from the fragments of DNA on the gel is then digitized and a computer used to make comparisons at this pattern with patterns from reference organisms available from a database. Ribotyping is both arapid and specific method of Bacterial identification for these reasons , ribotyping has found many applications in clinical diagnostics and for the microbial analyses of food, water and beverages.
Multilocus Sequence Typing
One of the limitations of both ribosomal RNA sequencing and ribotyping is that analysis focus on only a single gene. Multilocus sequence typing (MLST) circumvents these problems and is a powerful technology for characterizing strains at organisms within a species.
Author - Dr.Ruby Mam