Appropriate probe search method to specify groups in higher taxonomic ranks.

The article focuses on the method of specifying certain group in higher ranks of bacteria. Coincidence Ratio Inside Group (CRIG) and Coincidence Number Outside Group (CNOG) were proposed to make the search of probes systematic. Appropriate probes are found in all taxonomic ranks are found as a result of computer calculation. Moreover, such a method is useful for DNA chips or targeted PCR which can select a desirable bacteria set in any taxonomic rank. It is also in principle deterministic, and widely applied to any type of nucleotide sequences.