In June 1966, the British Nobel laureate Francis Crick helped to organise a meeting of the world’s leading geneticists at Cold Spring Harbour near New York. It was to be a triumphant event. For the previous decade and a half, biologists had been struggling to unravel the genetic code, the biological cipher that determines how genes are passed on to future generations and which controls the construction of proteins in our bodies.
This effort had begun in 1953 when Crick and his colleague James Watson showed that DNA was the critical constituent of our genes and revealed that it had a double helical structure. Since then, scientists had been racing to find out how that double helix controlled the manufacture of amino acids from which our bodies’ proteins are constructed. At Cold Spring Harbour, they were ready to announce their success and revealed the detailed process by which units of DNA control the manufacture of particular amino acids via intermediary entities known as ribosomes. This is the genetic code.
It was a historic occasion, as Crick acknowledged. Biologists had achieved an understanding of life’s processes at a molecular level for the first time, a point reinforced by Matthew Cobb in this meticulous, carefully assembled and thoroughly enjoyable history of modern molecular biology. “Cracking the code was a leap forward in humanity’s understanding of the natural world… akin to the discoveries of Galileo and Einstein in physics, or the publication of Darwin’s On the Origin of Species,” he states.
Yet it had not been an easy business, as Cobb also makes clear. The effort involved hundreds of scientists and was similar, in scale, to the Apollo moon landings or the Manhattan project – though with one key difference. There was no leadership, no overseeing council, and no directed funding from governments pursuing military or political goals.
Instead, a ragbag of modestly funded scientists – working in “the golden trio of Cambridge, Harvard and Paris” – used brilliant insights, audacious experiments and, above all, a lot of hard work to demonstrate how DNA controls protein synthesis. Those involved had no specific aims or policies and did not even have the chance to attend regular meetings to discuss progress.
Yet they succeeded, vanquishing pencil-chewing theorists who had pronounced how information was likely to be passed on by genes and who had made confident assumptions that were logical, rigorous – and invariably wrong. By contrast, intuition and inspired guesswork by experimenters revealed the true, startlingly chaotic, duplication-ridden process by which DNA directs the assembly of proteins.
With hindsight, this victory of experimentation over theory is unsurprising. “The code is a product of biology and is messy, illogical and inelegant,” says Cobb. For example, one amino acid – leucine – can be coded for by six different arrangements of DNA bases. This contrasts with the amino acid tryptophan, which can only be coded for by one such set of DNA bases. The genetic code is a haphazard business, it seems.
It is also riddled with redundancy, a result of billions of years during which evolution and chance events have added all sorts of oddities to the process. As the distinguished French biologist Jacques Monod noted, natural selection does not design, it tinkers with what is available. Hence the confounding of the armchair theorists and their ideas about the perfections of information theory.
The cracking of the genetic code has had a profound impact on society. In the short-to-medium term, it generated a host of Nobel prizes whose recipients included Monod, Max Delbruck, Sydney Brenner, Watson and, of course, Francis Crick, the nearest the code-crackers ever had to a leader. “Crick was not the Oppenheimer of the genetic code,” Cobb admits. “However, his intelligence, criticism and encouragement did much to create the essential insights that shaped how the science developed.”
In the longer term, entire new scientific disciplines, avenues of exploration and techniques were created by the code’s deciphering: DNA fingerprinting; a revolution in our understanding of inherited diseases and of cancer; the development of genetically engineered drugs and crops; and the sequencing of the genomes of modern humans and those of our ancient predecessors, including the Neanderthals. None of these scientific revolutions were apparent in 1966 and it is to Cobb’s considerable credit that he manages to provide such an authoritative but nevertheless thrilling narrative, while also establishing, on a more serious level, how the genetic code has made its impact on everyday life 50 years since its discovery. In short, this is a first-class read.
Life’s Greatest Secret: The Story of the Race to Crack the Genetic Code is published by Profile (£25). Click here to order a copy for £20
