Francois Jacob (a geneticist) and Jacques Monod (a biochemist) proposed a model of gene regulation, known as operon model in bacteria in 1961. Operon is a co-ordinate group of genes such as structural gene, operator gene, promoter gene, regulator gene which function together and regulate a metabolic pathway as a unit, e.g., lac operon, trp operon, ara operon, his operon, val operon etc.
Matthew Meselson and F. Stahl discovered the semi-conservative model of DNA replication in E. coli. Alfred Hershey and Martha Chase use T2 bacteriophage in their experiments to infect E. coli and proved that DNA is the genetic material. Alec Jeffreys (1984) invented the DNA fingerprinting technique. This technique determines nucleotide sequences of certain areas of DNA which are unique to each individual.