Cracking the Genetic Code: The History of Genetics

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Cracking the genetic code is something that is often discussed in the media while being worked on in genetic laboratories throughout the world. Genetic code is defined as the rule set by which the information that is encoded in genetic material is translated into proteins by cells that are living. DNA is made up of a code language of four letters that make up words, or codons, each three letters long.

Who Was Responsible?

Marshall Nirenberg, along with his National Institutes of Health colleagues, did the work to interpret the language of genetic code. Their careful and thorough work was conducted during the 1960s, and has paved the way for further work on interpreting entire human genome sequences. Other scientists, however, made some breakthroughs before Nirenberg that made it possible for him to make the breakthrough he did. They include Francis Crick, Rosalind Franklin, James Watson, and Maurice Wilkins. George Gamow also played a role.

Nirenberg, along with Heinrich Matthaei, started their experiments through studying the long linear molecule RNA and DNA. DNA nucleotides include adenine, cytosine, guanine, and thymine. In RNA, they include uracil which replaces thymine. They decided to use a cell-free environment. They chose E. coli bacteria cells to be their cytoplasm source. An E. coli extract was added to 20 test that all contained a mixture of 20 different amino acids. In each of the 20 different test tubes, a single amino acid was radioactively tagged. They monitored radioactivity for the reaction. Adding a “hot” amino acid would result in the development of a “hot” protein. In 1968, this research was awarded the Novel Prize in Physiology or Medicine.

How the Code is Used Today

Cracking the genetic code has made it possible to molecular biology to experience a tremendous boom which allowed scientists to produce selected proteins by putting together strings of RNA and DNA. One example of where this is widely utilized it pharmaceutical production. The DNA that encodes the desired protein is placed in bacteria and being synthesized. This results in the production of a new copy of the wanted protein every time the bacterium is divided. During an eight-hour working day, about 17 million daughter cells can be produced from an E. coli bacteria, and production is efficient. Because of this, it has become possible to create several useful proteins, such as insulin for patients with diabetes, and different coagulation factors for patients suffering from hemophilia.


American Chemistry Society. (2010). Deciphering the Genetic Code. Retrieved on September 5, 2010 from the American Chemistry Society:

The National Health Museum. (2010). The Genetic Code. Retrieved on September 5, 2010 from The National Health Museum: (2010). How the Code was Cracked. Retrieved on September 5, 2010 from