Replication and Maintenance of Bacterial Plasmids

摘要: By definition, plasmids are non-essential extrachromosomal elements. However, most bacteria carry at least one plasmid which can vary from a few kb to hundreds of and the component DNA in bacterial cell be as high 10% or more. A large proportion naturally occurring (as opposed ones that have been modified so they cannot transfer) transfer by means other — conjugative transfer, transduction even transformation. Since does not need recombine with endogenous become established new strain it allows genes carried on accessible many strains species where replicate. hi addition, if integrated into chromosome promote exchange chromosomal DNA. They thus facilitate sex between results recombination genes. In this way genre provides resource biodiversity communities draw under conditions selective pressure. Those individuals who possess best combinations plasmid-encoded for specific physical nutritional niche will dominate but persist minor components within community adjacent communities.