Replication origins, which are responsible for initiating the replication of eukaryotic chromosomal DNAs, are spaced at intervals of 40 to 200 kb. Although the sets of proteins that assemble at replication origins during G(1) to form pre-replicative complexes are highly conserved, the structures of replication origins varies from organism to organism. The identification of replication origins has been a labor-intensive task, requiring the analysis of chromosomal DNA replication intermediates. As a result, only a few replication origins have been identified and studied. In a pair of recently published papers, Raghuraman and colleagues and Wyrick, Aparicio and colleagues provide complementary microarray-based approaches to the identification of replication origins. These genome-wide views of DNA replication in Saccharomyces cerevisiae provide new insights into the way that the genome is duplicated and hold promise for the analysis of other genomes.

Copyright 2002 Wiley Periodicals, Inc.