Extrachromosomal DNA DNA in a variety of different organisms. Extrachromosomal DNA Extrachromosomal DNA is any DNA that is found outside the nucleus of a cell. It is also referred to as extranuclear DNA or cytoplasmic DNA. Most DNA in an individual genome is found in chromosomes but DNA found outside the nucleus also serves important biological functions. In prokaryotes, nonviral extrachromosomal DNA is primarily found in plasmids whereas in eukaryotes extrachromosomal DNA is primarily found in organelles. Mitochondrial DNA is a main source of this extrachromosomal DNA in eukaryotes. The fact that this organelle contains its own DNA supports the hypothesis that
DNA re-replication and Cdc6 expression. Loss of p53 regulation in cells can also be observed frequently in cell lines that overexpress Cdt1 or Cdc6. For the special case of cell cycle-regulated DNA replication in which DNA synthesis is uncoupled from cell cycle progression refer to endoreduplication. Endoreduplication is an important and widespread mechanism in many cell types. It does not adhere to many of the cell cycle checkpoints and damage controls in regularly dividing cells, but it does not result in uncontrolled re-replication. Endoreduplication is a controlled process and occurs to perform a specific cell function. In some cells, it has been