friedrich miescher extracted DNA for the first time from nucleus but he had no idea what the function of DNA was. years after that Oswald Avery discovered that DNA is the genetic material. the structure of DNA wasn't still discovered. after a lot of experiments done by a lot of scientists such as wilkins and franklin, finally watson and crick discovered the exact structure of DNA.
Friedrich Miescher was the first person to discover, identify and isolate DNA. Friedrich was a Swiss physician and biologist who was born in 1844. James D. Watson and Francis Crick the followed in his footsteps and discovered the double helix.