Replicon (genetics)

A replicon is a DNA molecule or RNA molecule, or a region of DNA or RNA, that replicates from a single origin of replication.

For most prokaryotic chromosomes, the replicon is the entire chromosome. The only exceptions found comes from archaea, where two Sulfolobus species have been shown to contain three replicons. Plasmids and bacteriophages are usually replicated as single replicons, but large plasmids in Gram-negative bacteria have been shown to carry several replicons (Thomas 2000, p. 3).

For eukaryotic chromosomes, there are multiple replicons per chromosome. The definition of replicons is somewhat confused with mitochondria, as they use unidirectional replication with two separate origins.