Physical map of a P. abyssi chromosomal segment
(sequence coordinates 118,000–128,000) carrying the predicted
replication origin (12). Locations of several restriction sites (H,
HindIII; N, NheI; E,
EcoRI; X, XbaI), probes used for
N/N 2D analyses are indicated. Fragments A (4.9-kb
NheI fragment), B (5.7-kb EcoRI
fragment), C (4.1-kb HindIII fragment), and D (5.6-kb
XbaI fragment) correspond to those analyzed in Fig. 2.
The central third of the each fragment [a bubble detection zone (18)]
is indicated by gray shading. A ≈1-kb boxed region upstream of, and
partially overlapping with, the P. abyssi cdc6 indicates
the region containing an active replication origin as demonstrated in
Fig. 2.