It is a surprise that the story of “life’s greatest secret” is only now being fully told nearly 50 years after the genetic code was cracked. While DNA’s double helix and the names James Watson, Francis Crick and Rosalind Franklin are legendary, how many people have heard of Marshall Nirenberg, Severo Ochoa and Har Gobind Khorana? These were the men who, following the discovery of the double helix in 1953, were largely responsible for working out the code – the set of rules by which the information within DNA controls the assembly and regulation of all the proteins in living cells.
Crick himself was the first to recognise that the bases along the double helix act to select from the 20 natural amino acids and to marshal them into a chain. The enigma came down to this: how could a mere four bases in DNA order the 20 amino acids that make up all proteins? It seemed that in this instance, as in many others, nature was a mathematician. Cicadas breed every 17 years, apart from one species that breeds every 13. Why 13 and 17? Because they are prime numbers. If it were 16 years, predators with two-, four- and eight-year life-cycles would coincide with the arrival of the cicadas: it has to be 17 or bust. Similarly, the spirals in sunflower heads and pine cones follow the mathematical Fibonacci series.
Continue reading...