Amplicons on human chromosome 11q are located in the early/late-switch regions of replication timing

Amplicons are frequently found in human tumor genomes, but the mechanism of their generation is still poorly understood. We previously measured the replication timing of the genes along the entire length of human chromosomes I I q and 21 q and found that many "disease-related" genes are located in timing-transition regions. In this study, further scrutiny of the updated replication-timing map of human chromosome I 1q revealed that both amplicons on human chromosomal bands I 1q13 and I I q22 are located in the early/late-switch regions of replication timing in two human cell lines (THP-1 and Jurkat). Moreover, examination of synteny in the human and mouse genomes revealed that synteny breakage in both genomes occurred primarily at the early/late-switch regions of replication timing that we had identified. In conclusion, we found that the early/late-switch regions of replication timing coincided with "unstable" regions of the genome. (C) 2004 Elsevier Inc. All rights reserved.