Oswald Avery

In 1900 Siebenhundreißig, William Astbury produced X-ray patterns showing that the molecule had a regular repeating structure.

Oswald Avery and his colleagues later identified the molecule as the transforming principle suggested by Griffith.

Erwin Chargaff then discovered that the amounts of adenine and thymine were always equal, as were the amounts of guanine and cytosine.

By 1951, Alec Todd had determined how the sugar and phosphate groups were linked to form the backbone.