Abstract
The methylation state of DNA can be transferred from generation to generation of cells, qualifying this gene-regulatory event as epigenetic. In his Perspective, Baylin discusses the new link between DNA replication and DNA methylation, demonstrated in this week9s issue, and speculates that this linkage is disrupted in tumor cells. On page 1996, Chuang et al. suggest that replication and methylation are linked through the binding of DNA-methyltransferase to proliferating cell nuclear antigen (PCNA).