DNA Replication Timing

1. Replication of eukaryotic chromosomes takes place in segments.
2. The rate of elongation of replication forks varies little throughout S phase.
3. It is the temporal order  of replication, not the sites of initiation, that is  conserved among species;
4. In multicellular  but not unicellular organisms, early replication  is correlated with transcriptional activity and is
   developmentally regulated.
5. The importance  of large-scale chromatin folding in the regulation of replication timing in both yeasts and  mammals.
6.