FIG. 4.

Maps of purE-pepN genotypes. Hyp, hypothetical ancestor containing the extended hif cluster and consisting of the purE-hicB region of R3001 affixed to the hifA-pepN region of Hib AM30 by the hicB-hifA junction of INT1. Genes and ORFs are depicted as arrows; fill patterns distinguishing genes are as indicated for class VI. Double-headed arrows, position of the combined hifA-hifB promoter region (not to scale); arrowheads at left and right, direct repeat units; asterisks within hifA, single-base frameshift deletions. Relative to Hib AM30, Δ₁ is a deletion removing 2,687 bp, including most of the hifA-hifB intergenic region on the hifB side of the promoter, hifB, and the first 1,226 bp of hifC (nt 1477 to 4164 in Hib AM30; accession no. Z33502); Δ₂ removes 130 bp within hifC (nt 4973 to 5102); and Δ₃ (534 bp) removes the 3′ terminus of hifC and 300 bp from the 5′ end of hifD (nt 5230 to 5763). In class III, another deletion (Δ_hifE) removes 1,189 bp (nt 6327 to 7515) from the 3′ end of hifE and the hifE-pepN intragenic region, ending just before the right direct repeat unit. +++, a 189-bp sequence found in IIb but not IIa (part of a 246-bp addition); it is followed by a second copy of the direct repeat unit.