Metagenomic Sized Fragments.

<p>Completed prokaryotic genomes were broken into metagenomically relevant fragments sizes of: 1,000 bp, 2,500 bp, 5,000 bp, 10,000 bp, 15,000 bp, 25,000 bp and 50,000 bp by extracting a random fragment of each length from each of the 1,424 genomes. The tetranucleotide and heptanucleotide based Euclidean distance was calculated between each fragment and these distances were used to construct cladograms. Each cladogram was analyzed for the percentage of organisms with a nearest neighbor belonging to the same genus and this percentage is plotted verses fragment length. Improvement is seen as fragment length is increased, but the improvement levels off at approximately 10,000 bp for tetranucleotide signatures and approximately 5,000 bp for heptanucleotide signatures, with heptanucleotide signatures are performing better at all fragment lengths.