Nirenberg and Matthaei experiment another. These experiments helped pave the way for the discovery of the structure of DNA. In 1953, with the help of Maurice Wilkins and Rosalind Franklin’s X-ray crystallography, James Watson and Francis Crick proposed DNA is structured as a double helix. In the 1960s, one main DNA mystery scientists needed to figure out was the number of bases found in each code word, or codon, during transcription. Scientists knew there was a total of four bases (guanine, cytosine, adenine, and thymine). They also knew that were 20 known amino acids. George Gamow suggested that the genetic code was made of
Francis Crick the protein alpha helix a few years earlier. The Watson and Crick discovery of the DNA double helix structure was made possible by their willingness to combine theory, modelling and experimental results (albeit mostly done by others) to achieve their goal. The DNA double helix structure proposed by Watson and Crick was based upon "Watson-Crick" bonds between the four bases most frequently found in DNA (A, C, T, G) and RNA (A, C, U, G). However, later research showed that triple-stranded, quadruple-stranded and other more complex DNA molecular structures required Hoogsteen base pairing. The entire field of synthetic biology began