operons
An operon is a functioning unit of genomic DNA that contains a cluster of adjacent genes that are co-regulated and transcribed together as a single mRNA under the control of a common promoter and regulatory elements. In its simplest form, an operon includes structural genes, a promoter, an operator sequence, and a regulatory gene that encodes a regulator protein. The operator is the DNA site where a repressor or activator can bind to influence transcription of the operon's genes. The regulator protein is typically produced in a separate location (in many bacteria) and acts in trans.
Most operons are found in prokaryotes, notably bacteria and some archaea, and they often enable coordinated
Regulation of operons can be inducible or repressible. In the lac operon of Escherichia coli, the presence
Historically, the operon model was proposed by François Jacob and Jacques Monod in 1961, establishing a framework