 The importance of McClintock 's contributions was revealed in the 1960s , when the work of French geneticists Francois Jacob and Jacques Monod described the genetic regulation of the lac operon , a concept she had demonstrated with Ac / Ds in 1951 . Following Jacob and Monod 's 1961 Journal of Molecular Biology paper " Genetic regulatory mechanisms in the synthesis of proteins " , McClintock wrote an article for American Naturalist comparing the lac operon and her work on controlling elements in maize . McClintock 's contribution to biology is still not widely acknowledged as amounting to the discovery of genetic regulation . 
