Loss of DNA Replication Control Is a Potent Inducer of Gene Amplification

Abstract

The Pitfalls of Re-Replication The cell has several layers of regulation to ensure that the genome is replicated once and only once during cell division, presumably to avoid the formation of duplicated sequences, which have the potential to recombine and compromise genome stability. In agreement with this idea, Green et al. (p. 943 ; see the Perspective by Kaochar et al. ) now show that re-replication of a marked yeast replication origin causes a significant increase in copy number variation in the region encompassing the origin. The observed duplications range in size from 135 to 470 kilobases and are almost all tandemly arrayed in a head-to-tail orientation. The duplicated regions are bounded by Ty repetitive elements and arise from nonallelic homologous recombination between the re-replicated repetitive elements.