Representation of the strands used for analysis in this paper. The leading strand for replication is black and the lagging one is shaded gray; note the switch at the origin of replication. The sense strand of coding sequences is represented by white arrows. The sense sequence of a coding region that is transcribed in the same direction as the motion of the replication fork is in the leading strand, whereas a sense sequence that is transcribed in the opposite direction is in the lagging strand. The strand used for large intergenic spaces, represented by large boxes, is always the published strand from 5' to 3'. The strand used for potentially transcribed untranslated spaces, that is, small intergenic regions among co-oriented genes, is represented by small boxes.