Physical maps and taxonomical relationships of the
gene. (A) A physical map of the tir gene from STEC O157 (GenBank accession number BA000007 gene ECs4561). A 1.6-kb region of the tir gene was sequenced from 22 STEC O157 isolates and the polymorphisms mapped on the tir gene along with previously identified functional domains. (B) Consensus tree from seven equally parsimonious trees constructed in PHYLIP (version 3.65)  with the program PARS and viewed in TreeView (version 1.6.6) . The tree was generated from seven variable sites (255 T>A, RR1-RU2, RR1-RU3, RR1-RU4, RR2, RR3 and RR4) and describes the taxonomical relationship of the tir nucleotide sequence with associated phenotypic and genotypic information. Ten genotypes resulting from one nucleotide polymorphism and four repeat region variations were identified from the 185 isolates. Colored boxes identify the different nucleotide variations and repeat units, while white boxes indicate missing repeat units. The sequences of the repeat regions are located below the colored boxes with the top line as the consensus sequence. A variant repeat unit (*) in repeat region 1 was identified that had the following sequence "AAAGGTGCTGGGGAGTTG".