The Operon Model of gene regulation in bacteria was first proposed by
Fancois Jacob and Jacque Monod predicted that there is a specific DNA sequence present near the transcription site of the Lac-operon gene which acts as a site for binding lac repressor. Thus, they were the first to propose the operon concept of gene regulation in prokaryotes.
Mendel after working on garden peas postulated the fundamental laws of inheritance. He stated that genes always come with two contrasting factors and are inherited as distinct units.
Francis Crick in the year 1958 proposed that the “DNA makes RNA, and RNA makes protein”, which is basically the Central Dogma of Molecular Biology.
Watson and Crick worked together on deducing the structure of DNA, the molecule that contains the hereditary information of the cells.