Shaping time: chromatin structure and the DNA replication programme

DNA is replicated according to a precise and reproducible temporal pattern. The S-phase programme has previously been analyzed in metazoan and yeast cells using different methods: cytological chromosome banding in human cells and DNA isotopic-labeling techniques in yeast. Microarray-based approaches for the analysis of the replication programme and chromatin structure are bringing us closer to a molecular understanding of the factors that determine replication time. In this article, I assess the impact of recent investigations and compare our knowledge of DNA replication-timing controls in yeast with those of metazoans.