Occasional Plasmids are Linear or Made of RNA

Single Stranded Plasmid Hairpin

Although most plasmids are circular molecules of DNA there are occasional exceptions. Linear plasmids of double-stranded DNA have been found in a variety of bacteria and in fungi and higher plants. The best-characterized linear plasmids are found in those few bacteria such as Borrelia and Streptomyces that also contain linear chromosomes (see Ch. 5). Linear DNA replicons in bacteria are not protected by incompatibility The inability of two plasmids of the same family to co-exist in the same...