|a small circle of bacterial DNA that is independent of the main bacterial chromosome. Plasmids often contain genes for drug resistances and can be transmitted between bacteria of the same and different species: used in genetic engineering|
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plasmid plas·mid (plāz'mĭd)
A circular, double-stranded unit of DNA that replicates within a cell independently of the chromosomal DNA and is most often found in bacteria; it is used in recombinant DNA research to transfer genes between cells. Also called extrachromosomal element.
|plasmid (plāz'mĭd) Pronunciation Key
A small, circular unit of DNA that replicates within a cell independently of the chromosomal DNA and is most often found in bacteria. Certain plasmids can insert themselves into chromosomes in places where there is a common sequence of nucleotides. Plasmids contain a few genes, which usually code for proteins, especially enzymes, some of which confer resistance to antibiotics. Plasmids are used in recombinant DNA research, especially to transform bacterial cells. See more at transformation.