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
Single-cell DNA template strand sequencing cellular processes. Briefly, pulse-chase assays allow researchers to track radioactively labelled molecules in the cell. In experiments used to study non-random chromosome assortment, stem cells are labeled or "pulsed" with a nucleotide analog that is incorporated in the replicated DNA strands. This allows the nascent stands to be tracked through many rounds of replication. Unfortunately, this method is found to have poor resolution as it can only be observed at the chromatid level. CO-FISH, or strand-specific fluorescence "in situ" hybridization, facilitates strand-specific targeting of DNA with fluorescently-tagged probes. It exploits the uniform orientation of major satellites relative to the direction