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We have completed the sequence of the bacterium Ureaplasma urealyticum serovar 3 (Uu), an opportunistic pathogen of the human urogenital tract that is a significant cause of adverse pregnancy outcome, neonatal disease, and supperative arthritis. The single circular chromosome of Uu contains 751,719 base pairs encoding 605 potential protein-coding Open Reading Frames (ORFs) and 38 RNA genes.
The DNA sequencing was done using a combination of complete random shotgun sequencing and ordered shotgun sequencing referred to as CROSS. Approximately 13,000 sequencing reactions were performed, and the average sequence redundancy was 7.0. At the completion of the sequencing phase of the project, the final two gaps were closed by sequencing directly from genomic DNA.
Uu is the third Mycoplasma genome to be completely sequenced, and analysis of the data indicates there is a substantial amount of genetic diversity among these mycoplasma species. The previously sequenced organisms, Mycoplasma genitalium (Mg) and Mycoplasma pneumoniae (Mp) are highly similar with all of the Mg ORFs (the smaller and simpler of the two bacteria) completely contained in Mp. However, there are a significant number of Mg and Mp genes with no orthologs in Uu, as well as a significant number of Uu genes with no orthologs in either Mg or Mp. In addition, while the gene order between Mg and Mp is largely conserved, with the exception of a few highly conserved operons (e.g. the S10, spc, and alpha operons), Uu gene order shows essentially no conservation with respect to Mg or Mp.