The pattern of replication along the −^ZFchromosome.

(A) Replication of the human 16p region was assayed by FISH as set out in Smith and Higgs4 using a set of 12 cosmids spanning this region. The pattern in an interspecific hybrid containing a normal copy of chromosome 16 (closed boxes) is compared with a hybrid containing the α−^ZF chromosome (open circles). In the α−^ZF chromosome, there is no value for Cos 12 (midpoint at approximate coordinate 177 000) because this region is deleted. Black dashed lines indicate the mean percent doublet scores for the early replicating control cosmids (top line) and late replicating control cosmids (bottom line). Below, the key features of the 16p region are shown. (B) Replication timing of control cosmids. The mean value for all early (p48) and late (cSamD4) mouse controls4 are represented as columns. Values for controls measured in the hybrid containing the α−^ZFchromosome are shown as a black diamond with lines representing plus or minus 1 SD.