Crick, Brenner et al. experiment

From Wikipedia, the free encyclopedia
Jump to: navigation, search

The Crick, Brenner, Barnett, Watts-Tobin experiment of 1961 was a scientific experiment performed in 1961 by Francis Crick, Sydney Brenner, Leslie Barnett and R.J. Watts-Tobin. They demonstrated that three bases of DNA code for one amino acid in the genetic code. The experiment elucidated the nature of gene expression and frame-shift mutations.

In the experiment, proflavin-induced mutations of the T4 bacteriophage gene, rIIB, were isolated. Proflavin causes mutations by inserting itself between DNA bases, typically resulting in insertion or deletion of a single base pair.

The mutants produced by Crick and Brenner could not produce functional rIIB protein because the insertion or deletion of a single nucleotide caused a frameshift mutation. Mutants with two or four nucleotides inserted or deleted were also nonfunctional. However, the mutant strains could be made functional again by using proflavin to insert or delete a total of three nucleotides. This proved that the genetic code uses a codon of three DNA bases that corresponds to an amino acid.


  1. Crick FH, Barnett L, Brenner S, Watts-Tobin RJ (December 1961). "General nature of the genetic code for proteins". Nature 192 (4809): 1227–32. Bibcode:1961Natur.192.1227C. doi:10.1038/1921227a0. PMID 13882203. 

See also[edit]