Life's Greatest Secret (14 page)

The speakers at the symposium showed how scientists were trying to apply the new concept of information to biology. One participant discussed Linus Pauling’s models of the molecular structure of the protein keratin in terms of the information they contained, while another explored the information content of a zygote, which he argued was ‘a set of instructions coded into the fertilized egg as dictated by the genetic constitution’. There were even two attempts to calculate the information contained in organisms. Henry Linschitz used molecular and energetic calculations to conclude that ‘the information content of a bacterial cell’ was around 10
¹³
bits.
³⁶
In a joint paper that was completed after Dancoff’s untimely death, Quastler outlined what he accepted were ‘crude approximations and vague hypotheses’ and then calculated that a human genome contains at most 10
¹⁰
bits of information. This calculation took as its starting point the view that each gene and its different versions, or alleles, is ‘an independent source of information, with an entropy which depends on the number of allelic states, or different messages’. Quastler admitted that he knew ‘neither the number of genes nor the average number of allelic states’, both of which would appear to be essential for such a calculation to be valid. Unperturbed, Quastler concluded: ‘this is an extremely coarse estimate, but it is better than no estimate at all.’
³⁷
Not everyone agreed. In 1965, after the genetic code had been cracked but before it had been completely deciphered, Michael Apter and Lewis Wolpert returned to Dancoff and Quastler’s figures and dismissed them as ‘so arbitrary as to make the values obtained meaningless’. Their conclusion about the pointlessness of Dancoff and Quastler’s calculation was cutting:

We believe that, on the contrary, they are not better than no estimate at all, since such estimates are liable to be misleading and to breed a false confidence.

Applying the new concepts of information to genetics was proving to be more difficult than many people expected.

*

It seemed that cybernetics and communication theory were going to sweep away everything in their path, changing the whole of science. But then some of its principal proponents were thrown into turmoil by personal and political events. The backdrop to the developments in cybernetics, and indeed the source of much of its funding, was the Cold War. In February 1949, the US lost its monopoly on nuclear weapons when the USSR exploded its first atom bomb. In 1950, the Cold War began to heat up as the Korean War broke out and the US fought a proxy war against the Russians and the Chinese. Shocked by these developments, the anti-communist John von Neumann pressed the US government to focus all its research effort on building a hydrogen bomb. Thanks in part to his lobbying, a major development programme began in which he was heavily involved, leaving little time for his other interests. The project culminated in the explosion of the first H-bomb in November 1952, with a yield that was nearly 1,000 times more destructive than that of Hiroshima. Nine months later, the USSR exploded its own thermonuclear device, and the arms race began in earnest. Von Neumann abandoned his interest in creating self-reproducing automata and spent much of the rest of his life until his death in 1957 working on intercontinental ballistic missiles, applying his mathematical genius to the potential destruction of the human race.
³⁹

In 1951 Wiener’s collaboration with Pitts and McCulloch, which had been at the heart of the development of cybernetics for nearly a decade, came to an abrupt end as he broke off all contact with the two younger men. Wiener had been severely irritated by a trivial but jocular letter sent by Pitts and McCulloch, but the source of the crisis appears to have been his wife’s malicious and entirely untrue suggestion that Pitts and McCulloch had seduced Wiener’s 19-year-old daughter Barbara. The cybernetics group was severely weakened and never recovered from the blow.
⁴⁰

Other thinkers were taking up the banner of cybernetics. In 1950 Hans Kalmus, a geneticist based at McGill University in Montreal who worked closely with J. B. S. Haldane, published a brief article in
The Journal of Heredity
entitled ‘A cybernetical aspect of genetics’. Kalmus had read
Cybernetics
and had been struck by what he called ‘certain unifying principles’ that shed an interesting light on heredity. Kalmus suggested that a gene ‘is a message, which can survive the death of the individual and can thus be received repeatedly by several organisms of different generations.’ Kalmus even claimed there was a parallel between what he called the racial memory of genes and the recently developed ability of computers to store information.
⁴¹

Kalmus went on to argue that there was no contradiction between the widely held enzymatic view of gene function and the cybernetic vision he was putting forward. Even more ambitiously, Kalmus tried to show how cybernetic concepts of feedback could explain interactions between genes at the genomic and populational levels, and interactions between genes and environmental factors – climate, other organisms and so on. However, Kalmus had little to say by way of detail and his ideas had no discernible influence. The first person to cite his article was … H. Kalmus, in 1962.
⁴²

As cybernetics and information theory became fashionable in fields far removed from automata and electronic communications, it became a target for ridicule. One example was a satirical letter to
Nature
that was cooked up over a well-oiled lunch in the Italian Alps, in September 1952.
⁴³
Boris Ephrussi and Jim Watson were dining with one of Ephrussi’s colleagues, Urs Leopold, and they decided to write a brief spoof letter, taking the mickey out of a recent review by Joshua Lederberg in which Lederberg had rather pompously suggested that several well-established terms in bacterial genetics should be replaced by fancy new words that he had invented.
⁴⁴

Ephrussi and Watson’s ‘joke’ consisted of satirically suggesting that words such as transformation, induction, transduction and infection, all of which had recently come into currency in bacterial genetics, should be replaced by the single term ‘inter-bacterial information’. Several points could have alerted the reader that this was not intended to be taken seriously. The suggested change did not make sense – ‘information’ could not be a grammatical substitute for ‘transformation’. Furthermore, the brief letter closed by reassuring the reader that their preferred term did ‘not imply necessarily the transfer of material substances’ – but the only alternative to a material transfer would be something like a radio broadcast between bacteria. The final phrase was equally facetious, as it highlighted ‘the possible future importance of cybernetics at the bacterial level’, conjuring an apparently surreal comparison of single-celled organisms with the most complex machines on Earth at the time.
⁴⁵

The editors of
Nature
did not get the joke – to be fair, it was not very funny – and they published the letter in the 18 April 1953 issue of the journal. At the time the letter met its deserved fate and disappeared into oblivion, apart from a couple of ironic citations from sharp-eyed bacterial geneticists who picked up on the attempt at humour.
⁴⁶
Recently, some historians have taken this apparently brilliant insight seriously, hypnotised by the sudden appearance of the words ‘information’ and ‘cybernetics’ in a letter signed by Jim Watson. The main historian who has studied this period, the late Lily Kay, argued earnestly that the letter represented a ‘gestalt switch’ in the thinking of the scientific community.
⁴⁷
Despite not ‘getting it’, Kay was absolutely right: the very fact that Ephrussi was poking fun indicated that concepts and words had changed. For Ephrussi and his boozy pals, information and cybernetics were now so commonplace that they could be used in an ironic spoof. The real irony was that this squib of a joke appeared in
Nature
just one week before the three articles that described the structure of DNA, and seven weeks before Watson and Crick changed our view of life by allying that structure with the term ‘genetical information’, this time used in a deadly serious fashion.

2. Spoof letter by Ephrussi and others to
Nature,
April 1953

* Not all the prose is sparkling. The conclusion to chapter 2 reads: ‘I do not wish to close this chapter without indicating that ergodic theory is a considerably wider subject than we have indicated above. There are certain modern developments of ergodic theory in which the measure to be kept invariant under a set of transformations is defined directly by the set itself rather than assumed in advance. I refer especially to the work of Kryloff and Bogoliouboff, and to some of the work of Hurewicz and the Japanese school.’

* Intriguingly, as early as the 1930s, the pioneering Cambridge physiologist Edgar Adrian was using the terms ‘information’ and ‘code’ to describe the activity of neurons – Garson, J. ‘The birth of information in the brain: Edgar Adrian and the vacuum tube’,
Science in Context,
vol. 27, 2015, pp. 31–52.

–     SIX     –

On 6 August 1945, when the atomic bomb destroyed Hiroshima, Maurice Wilkins was a 28-year-old British physicist working on the Manhattan Project. Like many of his colleagues, Wilkins had begun to have doubts about the morality of building the bomb as soon as Germany surrendered in 1945. The use of the bomb against Japan was the final straw. With his recent marriage in tatters and his love of physics poisoned by the horror of Hiroshima and Nagasaki, Wilkins returned to the UK.

Schrödinger’s
What is Life?
inspired Wilkins to use physics to investigate biology, so he approached his PhD supervisor, John Randall, who suggested that he should trace how the amount of DNA doubled just before a cell divided. The two men, who worked at the new Medical Research Council biophysics unit that Randall had set up at King’s College, London, knew of Avery’s work and felt that DNA was at the very least a vital component of nucleoproteins, if not the sole genetic material. In 1947 Wilkins met Francis Crick, whose physics PhD had been interrupted by the war. Crick had also read
What is Life?
and had also turned to biophysics. The two men became close friends, even though they had very different personalities – Crick was a noisy, brilliant magpie, with an eye for shiny new ideas, whereas Wilkins was quiet and reserved, with an odd habit of turning away from the person he was speaking to. He was also prone to suicidal thoughts and was in psychoanalysis.
¹

The friendship between Wilkins and Crick led to what is probably the most intensely studied moment in the history of twentieth century science: the discovery of the double helix structure of DNA. The events surrounding this event have been described in memoirs, biographies, exhibitions, TV programmes, countless academic articles, many inaccurate blog posts and even in a video rap contest.
²
* The story is of fundamental scientific importance and shows how science is an intensely human, collaborative and competitive enterprise in which luck, ambition and personality can play a central role. Above all, it was the advance that revealed the existence of the genetic code.

*

The King’s College biophysics unit was initially a minor player in the small world of groups that were studying the structure of DNA. The most influential work was being carried out in Columbia University by Erwin Chargaff, who was making a detailed biochemical analysis of the relative proportions of the four DNA bases – adenine, cytosine, guanine and thymine. Between 1948 and 1951, Chargaff showed that the four bases were not present in equal amounts; his conclusion was confirmed by Avery’s arch-critic, Alfred Mirsky, who by 1949 had become convinced that the old tetranucleotide hypothesis was ‘no longer tenable’.
³

Chargaff’s insight went much further. In 1951 he summarised the results he had published over the previous three years: different tissues of the same species yielded DNA with an identical composition in terms of the proportions of the four bases, and furthermore DNA molecules showed a ‘composition characteristic of the species from which they are derived’. DNA composition was constant in all tissues of a given species, but each species had its own profile. Even more importantly, he repeated a remarkable conclusion that he had come to the year before: