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
Pfu DNA polymerase and (1991)Patent 5,545,552 over "Pfu" itself was granted in August 1996. Pfu DNA polymerase "Pfu" DNA polymerase is an enzyme found in the hyperthermophilic archaeon "Pyrococcus furiosus", where it functions to copy the organism's DNA during cell division. In the laboratory setting, "Pfu" is used to amplify DNA in the polymerase chain reaction (PCR), where the enzyme serves the central function of copying a new strand of DNA during each extension step. "Pfu" DNA polymerase has superior thermostability and proofreading properties compared to "Taq" DNA polymerase. Unlike "Taq" DNA polymerase, "Pfu" DNA polymerase possesses 3' to 5' exonuclease proofreading activity,