Table - link
||Rogozin IB, Makarova KS, Natale DA, Spiridonov AN, Tatusov RL, Wolf YI, Yin J, Koonin EV. Congruent evolution of different classes of non-coding DNA in prokaryotic genomes. Nucleic Acids Res. 2002 Oct 1 30(19):4264-71. p.4266 table 1PubMed ID12364605
||COG - Clusters of Orthologous Groups of proteins (NCBI) link
||"[Researchers] analyzed the intergenic distances in 50 completely sequenced bacterial and archaeal genomes using the COG database (primary source) to limit the study to pairs of robustly predicted genes."
||"The number of genes and genome length vary widely among prokaryotes: the smallest of the analyzed genomes, M.genitalium, had 517 predicted genes, whereas the largest one, M.loti, had 7596 predicted genes. The average gene density per 1000 nucleotides is close to 1.0 for almost all genomes, with the notable exception of M.leprae, in which massive gene decay has been discovered, resulting in numerous long spacers containing pseudogenes (ref 25). The fraction of non-coding DNA in the analyzed prokaryotic genomes varied from 5 to 50% (Table 1) however, for 90% of the genomes, the fraction of non-coding DNA was <18%, the major outliers being M.leprae and R.prowazekii, two genomes of bacterial parasites enriched in pseudogenes (ref 25–27)."