The genome of Salmonella enterica serovar typhi

The generation of complete genome sequences provides a blueprint that facilitates the genetic characterization of pathogens and their hosts. The genome of Salmonella enterica serovar Typhi (S. Typhi) harbors similar to 5 million base pairs encoding some 4000 genes, of which 1200 are functionally inactive. Comparison of S. Typhi isolates from around the world indicates that they are highly related (clonal) and that they emerged from a single point of origin similar to 30,000 - 50,000 years ago. Evidence suggests that, as well as undergoing gene degradation, S. Typhi has also recently acquired genes, such as those encoding the Vi antigen, by horizontal transfer events.