Schematic representation of head-to-head genomic organisation of rif and upsA flanked var genes. Nine genes are flanked by a rif gene, which has its initiation codon approximately 3 or 4 kb upstream from the var initiation codon, and one var gene by another var gene at -2 kb. Punctured lines represent upsA, dotted lines upsA-rif and full line upsBsh. The diamond marks the putative termination site of upsA characterised by a stretch of TA repeats. Sizes of genes are not in scale.