Comparative genomics of Mycobacterium tuberculosis and Escherichia coli for recombination (rec) genes\ud

Despite the importance of \mathit{Mycobacterium tuberculosis} as a pathogen, the genetic basis of pathogenesis remains poorly understood. It is believed that allele exchange would facilitate understanding of the role(s) of specific genes that encode virulence determinants and help the conception of new therapeutic and prophylactic interventions. Although allele exchange has been achieved in \mathit{Mycobacterium smegmatis,} it has proved to be ineficient in \mathit{M. tuberculosis} due to the existence of an eæcient illegitimate recombination (IR) system. The molecular mechanism for the intrinsic resistance of\mathit{M. uberculosis} to allele exchange and increased frequency of IR remain obscure.\u