| 1869 | Johann Friedrich Miescher identifies a weakly acidic substance in the nuclei of human white blood cells. This substance later becomes known as DNA. |
| 1924 | Microscope studies using stains for DNA and protein show that both substances are present in chromosomes. |
| 1928 | Franklin Griffith discovers that genetic information can be transferred from dead bacteria cells to live ones. |
| 1944 | Oswald Avery, and his colleagues Maclyn McCarty and Colin MacLeod, identify the transforming agent discovered by Griffith as DNA. Many scientists believe that DNA is too simple a molecule to be the genetic material. |
| 1949 | Erwin Chargaff reports that DNA varies from species to species. He also finds that the amounts of adenine and thymine are equal, and also the amounts of guaninie and cytosine. |
| 1953 | James Watson and Francis Crick unlock the secret of DNA by discovering the molecular structure. This milestone in DNA history was perhaps the most important event regarding DNA. |
| 1962 | Francis Crick, James Watson, and Maurice Wilkins receive the Noble Prize for determining the molecular structure of DNA. |
| 1966 | The genetic code is deciphered when biochemical analysis reveals which codons determine which amino acids. |
| 1970 | Hamilton Smith isolates the first restriction enzyme, an enzye that cuts DNA at very specific nucleotide sequence. |
| 1978 | Somatostatin, which regulates human growth hormones, is the first human protein made using recombinant technology. |