FIG 1.

Genetic map of the soft core of conserved genes of 61 SXT/R391 ICEs. The soft core map is drawn to scale and based on conservation of genes in at least 57 of the 61 ICE representatives used in the analysis. Positions of the promoters are based on the work of Poulin-Laprade et al. (17, 18). Numbered loci in brackets contain shell genes. Locus 1 includes rumAB and its associated ISCR2 antibiotic resistance element, s024-s026, and the hot spot 5 (HS5) as described by Wozniak et al. (10). Loci 2, 3, and 4 correspond to variable DNA inserted at HS1, HS2, and HS4, respectively (10). Loci 5 and 6 correspond to orfZ and s070, respectively (15, 64). Locus 7 corresponds to s073 and variable DNA inserted at HS3, such as a trimethoprim resistance-conferring integron (10) or diguanylate cyclase genes (65). Locus 8 corresponds to the mercury resistance genes in R391.