Oligonucleotide profiling for discriminating bacteria in bacterial communities.

Based on the relative ratios of di- and tri-nucleotides in the DNA sequences, the profiles of 164 genome sequences from 152 representative microbial organisms were computed. By comparing the profiles of the genomes and their substrings with length 500 bps, the fluctuations of the relative abundances of di- and tri-nucleotides of these genomic sequences were analyzed. A new method to discriminate the origins of orphan DNA sequences was proposed, and the origins of 17 uncultured bacterium sequences from a bacterial community in the human gut were postulated and discussed.