A<unk> is the entire region of DNA that is independently replicated from a single origin of replication. A bacterial chromosome contains a single origin, and therefore the whole bacterial chromosome is a<unk>  The chromosomes of archaea and eukaryotes can have multiple origins of replication, and so their chromosomes may consist of several<unk> . The concept of the<unk> was formulated in 1963 by François Jacob, Sydney Brenner, and Jacques Cuzin as a part of their<unk> model for replication initiation. According to the<unk> model, two components control replication initiation: the replicator and the initiator. The replicator is the entire DNA sequence (including, but not limited to the origin of replication) required to direct the initiation of DNA replication. The initiator is the protein that recognizes the replicator and activates replication initiation. Sometimes in bacteriology, the term<unk> " is only used to refer to chromosomes containing a single origin of replication and therefore excludes the genomes of archaea and eukaryotes which can have several origins.
Replicon 
Insertion sequence
Cis-regulatory element
Pre-integration complex
Triage tag
TRNA 
Mutanome
Exosome 