Gene Replacement Mycobacterium tuberculosis and Mycobacterium bovis BCG

Much progress has been made in mycobacterial research in general and in mycobacterial genetics in particular during the past 10 yr. The complete genome sequences of two isolates of Mycobacterium tuberculosis , the widely distributed laboratory strain M. tuberculosis H37Rv (1 ) and a clinical isolate CDC 1551 (http://www.tigr.org ), have recently been determined, thus providing a complete blueprint of the genetic make-up of this pathogen.