Plasmids – potential tool for the investigation of gene transfer in Mycobacterium tuberculosis

Changes in the genetic repertoire by the acquisition of new genetic material through horizontal gene transfer is an important phenomenon in the evolution of many bacteria (Ochman & Moran, 2001). Transferred genes may either provide small but evolutionary important contributions to fitness or confer condition-specific advantages, facilitating adaptation to a new environment (Pal et al., 2005). Many bacterial pathogens have evolved the capacity to produce virulence factors that are directly involved in infection and disease. Acquiring virulence through horizontal gene transfer is the most common mechanism of gaining new genetic information (Ochman et al., 2000; Morschhauser et al., 2000; Hacker & Kaper, 2000; Ziebuhr et al., 1999). The need for information regarding gene transfer has prompted further investigation of different pathogenic organisms. Understanding gene transfer will explain the pathogenicity of the organism in the host.