Extrachromosomal Circular DNA are composed of chromatin and replicate in the nucleus of the cell during cell division. Unlike typical chromosomes, they are composed of circular fragments of DNA, up to only a few million base pairs in size and contain no centromere or telomere. Extrachromosomal Circular DNA Extrachromosomal circular DNA (eccDNA) is circular DNA found in the nuclei of plant and animal cells, including human cells, in addition to chromosomal DNA. eccDNA can be from 200 up to 5 million base pairs in length. eccDNA has been found in the nuclei of human cancer cells and shown to carry many copies of
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,