1865 : Gregor Mendel discovered, by crossbreeding peas, that specific laws govern hereditary traits (later referred to as Mendel's Laws).
1866 : Ernst Haeckel proposed the nucleus contains the factors responsible for transmitting hereditary characteristics.
1869 : Friedrich Miescher isolated DNA for the first time.
1871 : The first descriptions of DNA were published by Friedrich Miescher, Felix Hoppe-Seyler and P Plósz.
1882 : Walther Flemming described chromosomes and examined their behaviour during cellular division.
1910 : Thomas Hunt Morgan used fruit flies (drosophilidae) to study heredity and found the first mutant: a subject with white eyes.
1928 : Frederick Griffith discovered a “transforming principle” could be released by one strain of bacteria and integrated in others, transferring new genetic properties via heredity.
1941 : George Beadle and Edward Tatum demonstrated that each gene is responsible for producing one protein.
1949–1950 : Erwin Chargaff published his work on the nitrogenous base content of DNA and demonstrated the A+T/C+G ratio varies according to species, but is constant between members of the same species and the C/G and A/T ratios are always equal to 1.
1953 : Rosalind Franklin and Maurice Wilkins used X-rays to demonstrate that DNA has a repeated double helix structure.
1953 : James Watson and Francis Crick, pictured to the left, discovered the molecular structure of DNA: a double helix with base pairs of A + T and C + G.
1958 : Matthew Meselson and Franklin Stahl described how DNA replicates (semiconservative replication).
1972 : Paul Berg used restriction enzymes to create the first segment of recombinant DNA.
1977 : Frederick Sanger, Allan Maxam and Walter Gilbert developed DNA sequencing methods.
1983 : Kary Mullis invented the PCR process as an in vitro method for amplifying DNA.
1990 : Start of human genome sequencing.
1995 : The first complete genomic sequence of a free-living organism - Haemophilus influenzae bacteria - was published.
1999 : The first complete sequence of a human chromosome (22) was published.
2004 : Complete sequencing of the human genome was finished by an international public consortium.
2007 : HELYS proposes personalised works of art based on the DNA of its customers!