The study of sequence began with the investigation of biological macromolecules, particularly proteins, before extending to DNA. Early sequencing efforts started with proteins: Frederick Sanger's work in the 1950s on sequencing insulin demonstrated that proteins are composed of linear polypeptides with a defined order of amino acids, which was a foundational discovery for sequencing biology
. This protein sequencing work by Sanger earned him the Nobel Prize in Chemistry in 1958
. The study of DNA sequences began later, with the discovery of DNA structure in 1953 by Watson and Crick providing the conceptual basis that nucleotide sequences determine protein sequences and biological function
. The first DNA sequencing methods emerged in the early 1970s, with pioneering work by Ray Wu at Cornell University who developed a primer extension strategy in 1970, and by Walter Gilbert and Allan Maxam who developed chemical sequencing methods in the early 1970s
. Frederick Sanger developed rapid DNA sequencing methods in 1975 and 1977, including the widely used "dideoxy" chain-termination method, marking a major breakthrough in sequencing technology
. Thus, the study of sequencing began initially with protein sequencing in the mid-20th century, primarily through Sanger's work on insulin, and then expanded to DNA sequencing in the early 1970s with multiple researchers contributing to the development of sequencing techniques
