The initiation of DNA replication in eukaryotic cells is a highly regulated process that leads to the duplication of the genetic information for the next cell generation. This requires the ordered assembly of many proteins at the origins of DNA replication to form a competent, pre-replicative chromosomal stale. In addition to this competen : complex, at least two cell cycle regulated protein kinase pathways are required to affect a transition to a post-replicative chromosomal state. Protein kinases required to establish mitosis prevent re-replication of the DNA. As cells exit mitosis, the cell cycle is reset, allowing the establishment of a new, competent replication state.