Figure 3.

 A plasmid containing ARS301 as sole origin of replication replicates late in S phase. Replication of ARS301 on pCS1 was followed through S phase in comparison with the early-firing origin ARS305 on chromosome III and the late-replicating sequence R11 on chromosome V by density transfer as described in Materials and Methods. Percentage of replication of pCS1 (□), ARS305 (⋄), and R11 (○) is plotted against the time after release from a cdc7 block. Dotted (shaded) lines indicate the replication times t_rep for the three sequences of interest. See Table 1 for the times determined. t_rep is defined as the time when half of a specific sequence has replicated (i.e., shifted to the HL peak).