An independent DNA element, such as a plasmid, that can replicate extrachromosomally or that can be maintained by integration into the genome of the host.
A genetic element in bacteria that can replicate free in the cytoplasm or can be inserted into the main bacterial chromosome and replicate with the chromosome. Term used by Jacob and Wollman for genetic elements that can either exist independently in a cell or become integrated into the host chromosome.
A plasmid that may exist either free or integrated into a chromosome. (See plasmid.)