Submitted to: Canadian Journal of Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/16/2006
Publication Date: 6/14/2006
Citation: Marri, P.R., Bannantine, J.P., Paustian, M., Golding, G.B. 2006. Lateral gene transfer in Mycobacterium avium subspecies paratuberculosis. Canadian Journal of Microbiology. 52:560-569. Interpretive Summary: This manuscript documents the first report of over 200 bacterial genes taken up by Mycobacterium avium subspecies paratuberculosis (MAP) and incorporated into its genome. The technique used to determine which genes were scavenged is more complex than simply checking for changes in the guanine and cytosine content of the DNA sequence. It involved first identifying, by similarity searching of databases, which genes are unique to MAP. Then a bootstrap analysis was performed on those sequences to give statistical confidence that the gene was acquired in the described manner. The implications for the uptake of these genes are also discussed.
Technical Abstract: Lateral gene transfer is an integral part of genome evolution in most bacteria. Bacteria can readily change the contents of their genomes in order to increase adaptability to ever changing surroundings and to generate evolutionary novelty. Here, we report instances of lateral gene transfer in M. avium subsp. paratuberculosis (M. a. paratuberculosis), a pathogenic bacteria that causes Johne’s disease in cattle. A set of 275 genes are identified that are likely to have been recently acquired by lateral gene transfer. The analysis indicated that 53 of the 275 genes were acquired after the divergence of M. a. paratuberculosis from M. avium subsp. avium while the remaining 222 genes were possibly acquired by a common ancestor of M. a. paratuberculosis and M. avium subsp. avium after its divergence from the M. tuberculosis complex. Many of the acquired genes were from proteobacteria or soil dwelling actinobacteria. Prominent laterally transferred genes include rsbR - a possible regulator of sigma factor and the genes designated MAP3614 and MAP3757, which are similar to genes in eukaryotes. The results of this study suggest that, like most other bacteria, lateral gene transfers seem to be a common feature in M. a. paratuberculosis and that the proteobacteria contribute most of these genetic exchanges.