Watson and Crick- The structure of DNA

By Rocque Gratrix

It is the year 1951 a genetic model of heredity is in the horizon but the pieces of the structure do not fit together. A 3-dimensionsal model is required to answer the question how is genetic material passed through heredity. Geneticists struggled with this question for years and while developing clues to the answer the double helix remained a mystery, until finally in 1953 two unknown scientist proposed a structure for DNA. It was James Watson and Francis Crick that would leave their mark in genetic history.

James Watson a phage geneticists and Francis Crick a physicist were the ones to put all the pieces into place. Matching nucleotides together with their complementary base or simply A’s with T’s and G’s with C’s. This paring allowed the structure of DNA to have a uniform width along the length of the strand. This also solved the problem of replication because both strands were complementary and could be used as templates for daughter strands.

Watson and Crick’s finding opened many new doors in biology. The implication of the double helix affects every living organism and has tremendously opened the field of genetics. Even now we are only beginning to scratch the surface in gene therapy and genetic manipulation. Watson and Crick never could have fathomed the implications of their discovery in 1953.

However Watson and Crick did not solely discover the structure of DNA. Other scientist’s such as Rosalind Franklin aided in a secondary way to the discovery. She took an X-ray diffraction photo of DNA that allowed Watson and Crick to deduce the double helix structure. Erwin Chargaff a biochemist discovered that DNA composition is species specific and ratios of DNA differ between species. This discovery led him to see a direct correlation between base pairs. He found that the ratio of Adenine was identical to that of thymine and the ratio of guanine was identical to that of cytosine, which was key in the formation of complimentary strands. It was all these pieces of evidence that allowed Watson and Crick to develop a final hypothesis and fit the DNA structure together. Watson, Crick and Maurice Wilkins received the Nobel Prize in 1962 for their work on the double helix.

Questions

1. Do you feel that Watson and Crick are solely responsible for the discovery of the structure of DNA? If yes, why?

2. List some important aspects on how Watson and Crick’s discovery has influenced biology up to today.

3. How important is the sharing of information in the scientific community?

4. What are some new fields of science that have developed due to the discovery of the double helix?