PathwayStep4582 PathwayStep4577 PathwayStep4570 PathwayStep508 Synthesis of DNA S Phase DNA synthesis occurs in the S phase, or the synthesis phase, of the cell cycle. The cell duplicates its hereditary material, and two copies of the chromosome are formed. As DNA replication continues, the E type cyclins shared by the G1 and S phases, are destroyed and the levels of the mitotic cyclins rise. GENE ONTOLOGYGO:0000084 Reactome Database ID Release 4369242 Reactome, http://www.reactome.org ReactomeREACT_899 Reviewed: Manfredi, J, 0000-00-00 00:00:00 Cyclin A:Cdk2-associated events at S phase entry Ubiquitin-dependent degradation of Cyclin D Establishment of Sister Chromatid Cohesion