FIG 4 .

Gene replacement event indicative of replacement of the emm12-sic region with the mrp82-emm82 region. The parental donor (orange) and recipient (blue) strain chromosomal regions are indicated on the basis of observed sequence homologies. The homologies observed suggest that the gene replacement event involved a large isp–His triad-encoding gene region, followed by a deletion event facilitated by homologous sequences in the tandem emm82 and enn82 3′ regions. The inactivating frameshift in sof12 (indicated by sof12*) was removed by a single base insertion (indicated by sof12⁺). Additional recombination events involving unknown donors are indicated by gray zones in the isp and scpA downstream region.