Watson & Crick 1953 - Double Helix Structure of DNA

James Watson and Francis Crick studied at the University of Cambridge. They became interested in Linus Pauling's work of a proton having an alpha helix structure, that spiraled in a coil. Watson also became interested in Rosalind Franklins research of DNA existing in two forms and an X-ray diffraction image of DNA.(1)

Watson and Crick found that there are two chains of nucleotide; one going up and one going down, each containing a long chain of monomer nucleotides.(2)

With the help of Erwin Chargaffs findings, they added that matching bases pairs interlocked in the middle of the double helix to keep the distance between the chains constant. Each strand of the DNA molecule was a template for the other.(1) DNA replicated itself and separating into two different strands. Those strands then became templates for new double-helix.

Resources
1.PBS- Watson and Crick

2. Nature - Watson and Crick

3. History