A circular DNA molecule that is maintained separately from the cell’s chromosomal DNA and is capable of replicating itself. Plasmids are found mainly in bacteria and also in some eukaryotes, and may encode genes for antibiotic resistance.
An autonomously replicating, extra-chromosomal DNA molecule found in many bacteria. Plasmids are widely used as carriers of cloned genes.
An independent, stable, self-replicating piece of DNA in bacterial cells that is not a part of the normal cell genome and that never becomes integrated into the host chromosome. This is in contrast to a similar genetic element known as an episome plasmid which may exist independently of the chromosome or may become integrated into the host chromosome. Plasmids are known to confer resistance to antibiotics and may be transferred by cell-to-cell contact (by conjugation via the sex pilus) or by viral-mediated transduction. Plasmids are commonly used in recombinant DNA experiments as acceptors of foreign DNA. Known forms of plasmids include both linear and circular molecules.
A small extrachromosomal circular molecule that replicates independently of the host DNA.
Small cellular inclusion consisting of deoxyribonucleic acid (DNA), capable of self-replicating, and involved in certain metabolic functions.
A generic description of any discrete agents in cells that have genetic functions. They include plasmagenes (self-reproducing copies of a nuclear gene existing outside the cell nucleus) and viruses.
A piece of extrachromosomal, double-stranded DNA found in most bacteria. Plasmids replicate when a bacterium divides and are passed to subsequent cells. The products of plasmid genes are enzymes that provide resistance to antibiotics or that synthesize bacteriocins or other toxins.