plasmidn.

1952 J. Lederberg in Physiol. Rev. 32 403 I propose plasmid as a generic term for any extrachromosomal hereditary determinant.

1964 Daily Mirror 24 July 8/2 The Rogue Bug's real name is RTF plasmid—R.T.F. stands for Resistance Transfer Factor. It is a tiny particle that appears to move from one bacterial cell to another, carrying with it a built-in resistance to new drugs.

1973 R. G. Krueger et al. Introd. Microbiol. xv. 421/1 There are..transmissible plasmids or sex factors like the F factor, which promote their own transfer to recipient bacteria, and there are nontransmissible plasmids which are incapable of transferring themselves to recipient cells.

1975 Sci. Amer. July 25 It has been called plasmid engineering, because it utilizes plasmids to introduce the foreign genes... Because of the method's potential for creating a wide variety of novel genetic combinations in microorganisms it is also known as genetic engineering.

1984 M. J. Taussig Processes in Pathol. & Microbiol. (ed. 2) iv. 472 The ends of the foreign DNA insert are joined to the ends of the plasmid by another enzyme (a ligase) to re-form a circular molecule in which plasmid and foreign DNA have been recombined.

2004 Capital Times (Madison, Wisconsin) (Nexis) 7 Oct. 6 f Patients will be injected with plasmid DNA (pDNA) molecules that carry the genetic instructions to produce EPO [= erythropoietin].