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Fifty Years of the Genetic Code

In the fifty years since the landmark presentation of the preliminary identification of all 64 codons that make up the genetic code, the deciphering of the code has opened a universe of opportunity in scientific and medical discoveries. This accomplishment was recently marked with a symposium to Honour Marshall Nirenberg. Brian Clark was coorganiser of the meeting.

2014.09.09 | Lisbeth Heilesen

The fifty years' anniversary of Marshall Nirenberg's presentation of the preliminary identification of all 64 codons that make up the genetic code was recently marked with a symposium to Honour the Legacy of Marshall Nirenberg. Photo: Professor Myrna Weissmann, Columbia University, USA.

Programme for the meeting - click photos for enlargement.

Nirenberg’s work enabled all biologists and chemists to understand and control the various cellular molecular mechanisms that have had tremendously positive outcomes in molecular medicine for which NIH continues to be famous and the genetic code gives us an insight into function which the DNA informational strands cannot.

The presentation of the codons took place at the IUB meeting in New York City on 31 July 1964, and exactly fifty years later, a symposium was held in New York City to honour the legacy of Nobel Laureate Marshall Nirenberg for his accomplishment and its impact on many aspects of science.

Professor Emeritus Brian Clark from the Department of Molecular Biology and Genetics attended this prestigious symposium at the New York Academy of Sciences in New York City.  Brian Clark  was chosen to be one of the organisers because he had worked in Marshall Nirenberg’s original group at the National Institutes of Health in Bethesda, Maryland from 1962-1964 when the deciphering of the Genetic Code took place and because he was a former President of the International Union of Biochemistry and Molecular Biology (IUBMB), formerly the International Union of Biochemistry (IUB).  He has drawn the parallel between how the Rosetta Stone enabled our culture to decipher the Egyptian hieroglyphics and how the Genetic Code enables us to dechipher the string of DNA bases.

When Brian Clark was in the final year of his PhD studies, his supervisor, Dan Brown took a sabbatical leave and Professor Alexander Todd took over.  When Dr Clark expressed an interest in Biochemistry he arranged for him to take up a Research Associate position with Professor J. M. Buchanan, an expert in nucleic acid component’s metabolism at Massachusetts Institute of Technology (MIT).  While at MIT the news of Marshall Nirenberg’s talk at the IUB Congress in Moscow in 1961 spread quickly and stimulated a host of competitors.  In the autumn of 1961, Nirenberg gave a full house seminar at MIT on the synthetic mRNA work showing that polyU made polyPhe.  His friends and eminent scientists were eager to support him and thought that Brian Clark’s expertise in organic chemistry would be useful to him.  Jack Buchanan helped by releasing him from a 3-year contract at MIT, and he signed up with Nirenberg.

When he arrived at NIH in September 1962, Phil Leder and Sid Pestka had just arrived while Bill Sly, Bill Jones and Heinrich Matthei had just left.  Nirenberg worked closely with his MD recruits and technicians Norma and Theresa. Dr Clark had more freedom and was able to try new things.  He was extremely impressed by Nirenberg’s strategy of looking for quick methods, especially when making an active cell-free system, the analysis of polypeptide products were painstakingly long.  Then came the triplet binding assay developed with Phil as they wanted to synthesise trinucleoside diphosphates (triplets).  All hands in the rapidly growing group tried all sorts of methods, even making degradable enzymes work backwards.  Already at the time of the Cold Spring Harbor Symposium in 1963, the group had made very significant progress in assigning triplets to amino acids, and by the time of the IUB Congress in New York on 31 July 1964, most of the genetic code was decoded. (Hence the date for this symposium). 

The MRC Laboratory of Molecular Biology in Cambridge worked on the elucidation of the code using molecular genetics so needed a biochemical approach.  They offered Brian Clark a staff position to work on punctuation of the code, which at that time was not being worked on at NIH so he moved at an appropriate time.

Dr Clark thinks that the biggest tribute he can pay Marshall in terms of his character, curiosity, humility and generosity is that he reminds him of the most lauded and admired scientist, the double Nobel Prize Winner Fred Sanger.  Fred worked at the bench all his life with obvious green fingers.  His modesty and curiosity in the work of others had no bounds.  Marshall was of the same mould, a rare phenomenon these days.  He was a gentle, enquiring, friendly, generous man who accomplished the most important biological discovery of his time – the Rosetta Stone of Biology.


The Symposium was a splendid success with many high level scientists attending enthusiastically, including good wishes in a video presentation by the Director of the NIH, Francis Collins.  In addition, 100 selected advanced students were among the 250 participants.

Scientific Organising Committee:
C. Thomas Caskey, Baylor College of Medicine, Houston, Texas; Brian F. C. Clark, Aarhus University; Jennifer Henry, New York Academy of Sciences; Gregory A. Petsko, Weill Cornell Medical School, New York and Brandeis University.

Co-sponsors: the International Union of Biochemistry and Molecular Biology (IUBMB) and the New York Academy of Sciences (NYAS).

IUBMB seeks to advance the international molecular life sciences community by promoting interactions across the diversity of scientific endeavours.

NYAS is an independent, not-for-profit organisation that since 1817 has been committed to advancing sciences, technology, and society worldwide. 


For further information, please contact

Professor Emeritus Brian F.C. Clark
Department of Molecular Biology and Genetics, Aarhus University
bfcc@mb.au.dk - +45 4046 3410

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