Deletion and pseudogene formation in the four human-adapted typhoidal strains.

Note: we divide the presumably lost genes, relative to S. typhimurium LT2, into three categories: 1, they are all pseudogenes in the four typhoidal strains; 2, they are pseudogenes in S. paratyphi C but entirely absent in S. typhi and S. paratyphi A; and 3, other genes in the same or a similar pathway are either pseudogenes or absent.