Genes By AHAS Jan 28, 1865 Introduction of the concept of 'particles' which would later be known as genes by Gregor Mendel Introduction of the concept of 'particles' which would later be known as genes by Gregor Mendel Sep 29, 1900 Basic structure of DNA known Sep 29, 1950 Experiments by Oswald Avery, Colin MacLeod and Maclyn McCarty proved DNA to contain genes Sep 29, 1951 Erwin Chargaff had observed that the proportion of cytosine and guanine were the same. Which held true for adenine and thymine as well. Sep 29, 1951 Linus Pauling correctly proposes the α-Helix model for DNA Sep 29, 1953 X-ray diffraction by Rosalind Franklin yields best results, produces the two stranded helical model Sep 29, 2014 Using Rosalind Franklin's findings, James Watson and Francis Crick assembled the double helix model