J D Bernal

by Andrew Brown

  15

  Central Dogma

  In the 1930s, the Rockefeller Foundation supported several small European meetings where physicists were invited to pollinate the debate about fundamental problems in biology. One of these gatherings took place at Klampenborg, about ten kilometres from Copenhagen, early in April 1938. A mixed British contingent of scientists, with Astbury and Bernal representing X-ray crystallography, attended. The crossing from Harwich to the Hook of Holland was distinctly rough, and while most of the party attempted to sleep despite the rolling of the ship, Bernal sat up in the second-class lounge deep in conversation with a tall, rather sleek, young man. His companion was Cyril Darlington, Director of the John Innes Horticultural Institute – a geneticist who had recently written on the coiling of chromosomes. Darlington had proposed that this observable alteration in chromosomal form might be due to an invisible molecular spiral in the constituent nucleoprotein. During the night, Darlington taught Sage ‘all the genetics and cytology anyone needs to know’.1

  The main focus of the Klampenborg meeting was on the physical mechanics of changes in chromosomes that had been observed under the light microscope at different stages of the cell cycle. Darlington’s ideas on ‘relational coiling’, the term he used to describe two chromosomal threads coiling around each other, were central to the discussions, and suggested to Hal Waddington that ‘the internal genes have some spiral arrangement’ that produced this effect. It was still believed that the ultimate genetic structure was protein, although the nucleic acid DNA was now accepted to be a constituent of chromosomes. Bernal offered some ideas on what physical forces might bring pairs of homologous chromosomes together during the development of sex cells (sperm or ova) and also prevent other chromosomes from becoming entwined. This process in which genetic material can cross over from one chromosome to its homologue, or matching partner, results in the assortment of genes during sexual reproduction so that offspring are not genetically identical to their parents or to their siblings.

  Sage returned to this subject on his pre-war lecture tour of the USA, elaborating on ideas he had first considered at the Klampenborg meeting. He predicted, incorrectly as it would turn out, that the ‘fundamental question of the molecular structure of the chromosomes must necessarily wait for its full elucidation on the knowledge of protein structure’. His next statement would be borne out in time, however, that the chromosomes’ molecular structure bore a ‘marked similarity of chemical composition to the viruses of the tobacco-mosaic type [suggesting] that it is also a long-moleculed nucleoprotein with internal crystalline structure’.2 In his American talk, he proposed the novel ‘zipper hypothesis’ of chromosome pairing. He based his argument on the assumption that there would be a difference in energy states when homologous parts of chromosomes (that carry genes for the same traits) come together versus the case for non-similar lengths of chromosomes.

  The principle is the same physically as that accounting for the immiscibility of oil and water. Water molecules attract water molecules, and they also attract oil molecules even more than oil molecules attract each other, but the greater attraction between water molecules for each other forces the oil out. Granted this mechanism, the like-to-like approximation of chromosomes becomes the position of lowest energy, but since it is only one of innumerable arrangements, it would be so improbable as not to occur if there were not a further mechanism. The chromosomes as a whole are in movement in the cell fluid, and if two chromosomes happen to touch at some point where they have no homologous parts, we must assume that the energy of interaction is not sufficient for them to remain long in this position; if, however, the parts are homologous, the moment they touch all the other parts up and down from the point of contact will also be homologous, the process of approximation will spread, and it will be no longer possible for the thermal motion to separate them. This may be called the zipper hypothesis of chromosome pairing.3

  Sage was theorizing about the physical and structural aspects of genetic material, questions soon to become the province of molecular biology; there was also an older tradition continuing within genetics – the study of gene expression – that started with the pioneering observations of Mendel in the nineteenth century. The John Innes Horticultural Institute, where J.B.S. Haldane worked for some years and which was now directed by Darlington, continued the Mendelian approach by concentrating, for example, on the genetically determined chemical reactions that produce plant pigments. British genetics research was modest in scale, and did not compare with what was going on in the Soviet Union under the direction of Nikolai Vavilov. Vavilov had spent two years at the Innes Institute as a researcher just before the First World War, and in 1921, at the age of thirty-six, was picked by Lenin to be the president of the Lenin Academy of Agricultural Sciences. Over the next decade, he built up more than four hundred research institutes and experimental stations across the vast Soviet Union, employing thousands of research workers.4 Sage knew him quite well, meeting him first at the 1931 Congress on the History of Science in London and then on subsequent visits to the USSR.

  In 1933, Vavilov persuaded Hermann J. Muller, the leading American geneticist, to come and work with him.5 It was not a difficult decision for Muller, who had already jumped from the frying pan of racist Texas, where he was under FBI surveillance for subversive political activity, into the Nazi-stoked fire of Berlin. Muller lost no time in establishing his credentials as a good Marxist, by comparing the favourable opportunities for research in the USSR with those in the USA, and by delivering a paean on ‘Lenin’s doctrines in relation to genetics’. He showed how his approach to genetics was consistent with dialectical materialism, and pledged himself not just to advance the understanding of genetics through his research, but to apply its fruits to the improvement of human society.

  Vavilov himself had spent his career trying to improve the state of Soviet agriculture through careful studies of plant genetics, but had been completely upstaged in Stalin’s eyes by Trofim Lysenko, a cunning and ambitious peasant’s son from the Ukraine.6 Lysenko, who had no formal scientific education, first came to attention in the mid-1920s, when he made extravagant claims for a technique known as vernalization, which involved chilling seeds of wheat before planting them in the spring. Lysenko promised that yields would be increased by forty per cent – welcome news in a land where harsh winters and the collectivization of agriculture had resulted in widespread famine.

  Lysenko fabricated results from limited field trials of vernalization; these were initially accepted at face value by Vavilov and other reputable scientists, and satisfied a political leadership unconcerned with the truth. Lysenko exemplified how a peasant could become a hero in the socialist system: he was put in charge of his own institute in Odessa, made a member of the Ukrainian Academy of Sciences and, in 1935, awarded the Order of Lenin by Stalin. By this time, genuine scientists in the USSR were beginning to recognize Lysenko as a charlatan and to point out the damage done by the uncritical and widespread acceptance of vernalization. Far from being over-awed by these criticisms, Lysenko went on the offensive, publicly denouncing Vavilov for distorting the truth and orchestrating attacks on genetics as a bourgeois indulgence. Sensing that vernalization was no longer worth promoting, Lysenko replaced it with an even more outlandish notion, namely that he could transform the nature of plants at will, turning winter wheat into spring wheat for example. An incredulous Vavilov challenged this claim at a conference by asking, ‘You can refashion heredity?’ Lysenko calmly affirmed that he could, before unleashing a tirade against the whole concept of genetics. As a final irony, he castigated Muller (who had been the first to demonstrate that genes could be mutated or altered by X-rays), as being guilty of the ‘geneticists’ fundamental mistake… they accept the immutability of genes over a long line of generations’. Lysenko and his school, by contrast, could with their plant raising methods ‘change the nature of plants in a controlled manner in each generation’.7

  Lysenko presented som
e sensational results from his Odessa institute at a meeting of the Lenin Academy of Agricultural Sciences in Moscow in December 1936. Following his unspecified treatment, characteristics acquired by plants could be inherited by the next generation so that winter wheat could be transformed into spring wheat and vice versa. Muller, who was a vocal participant at the meeting, forced Lysenko to admit that ‘when he claimed the effect of treatment was inherited, he was basing his statement on the fact that only one seed out of a field full survived and that this transmitted the supposedly induced traits’.8 It was obvious to Muller that the solitary surviving seed could be a contaminant or a mutation, and that Lysenko’s one hundred percent success was ‘because the number one out of one is 100%’. The schism in Soviet genetics was now public enough to be noticed in the West, and Darlington wrote a news piece for Nature in January 1937, reporting

  … there was a general attack on the present position of research in genetics. The grounds of the attack were ostensibly twofold. First, geneticists like Muller and Vavilov were said to have ignored the Marxian principle of the unity of theory and practice in failing to keep their work in touch with the needs of farmers. Secondly, the primary assumptions of genetics were said to be invalid. Presumably, in the absence of other evidence, the second contention was deduced from the first. The attack was reinforced by pointing to work like that of Michurin and Lysenko which, unhampered by academic prejudice, has yielded results of immense practical value by methods of trial and error.9

  The issue concerned Lancelot Hogben, a biologist and old friend of Sage’s, whose doubts about Soviet communism, combined with his tetchy nature, were putting him at odds with less sceptical scientists on the left. He wrote to Sage in February 1937, revealing his disenchantment:

  You orthodox Marxists are much more pleased if a man thinks the wrong thing with the right religious formulae than whether he is concerned with arriving at correct conclusions. If he has the mischance to do so by employing the lucidities of his native tongue, the only thanks he gets is to be called a Fascist.10

  Admitting to complete bafflement in the face of Marxist thinking, Hogben characterized dialectical materialism, as ‘first stating a plain lie and then stating another plain lie and then applying an elaborate process of casuistry to square one plain lie with the other’. As an example he cited,

  … the recent incident over the Genetics Congress in Russia. This has destroyed 50% of the sympathy which some of us would like to build up among the scientific workers for the constructive achievements of the USSR. I believe it is a plain duty to expose this nonsense…

  Whatever concerns some British scientists might have registered, inside the USSR the die was cast. Lysenko’s outrageous tactics worked to the extent that he found himself elevated to membership of the Supreme Soviet, a position from which he literally looked down on Stalin at Kremlin meetings. To oppose Lysenkoism now called into question the ideology of his detractors, who were painted as fascist sympathizers opposed to the Stalin Constitution. Even before Lysenko’s elevation to the highest level of the Soviet system, the terrors had begun for geneticists. Two of Muller’s closest colleagues, both of whom had spent time in his Texas laboratory on Rockefeller grants a few years before, suddenly disappeared in 1936. Israel Agol was denounced as ‘another Trotskyite bandit’ and Solomon Levit, the head of the Medico-Genetics Institute in Moscow, was falsely accused of holding fascist views on eugenics: both men perished in prison.11 Muller was told not to ask about them by Russian friends. He managed to leave the Soviet Union in September 1937, and with help from Julian Huxley, secured a post at the Institute of Animal Genetics in Edinburgh.

  After his accession to the top, Lysenko was complicit in the growing persecution of biologists, who were a small but important group in Stalin’s paranoid eyes. The pervasiveness of the threat was such that Muller did not dare to criticize Lysenko even after arriving in Edinburgh, for fear that his words would travel back to the Soviet Union and endanger his former colleagues. He did take note of the attitudes of British biologists and confided to an American friend in December 1937 that ‘Hogben and Gordon… are revising their outlook in view of recent happenings in the USSR, and are much upset, but Haldane is 100%’.12 Indeed Haldane’s loyalty to the Soviet system was so complete that he suppressed a mathematical paper on genetics that one of Muller’s former students, Vladimir Efroimson, had managed to smuggle out of a Siberian labour camp.13

  In his 1937 Nature article calling attention to the doctrinal threat to the scientists at the Lenin Academy of Agricultural Sciences, Darlington had written that if Lysenko’s claims were true ‘the tedious methods of plant breeding now practised by orthodox geneticists in Prof. Vavilov’s institutions would of course be superfluous’.14 Lysenko plainly agreed with him because when he finally managed to secure the presidency of the Academy in 1938, his first move was to announce in an article in Pravda that the research staff should be cut at least by half to improve productivity, and he put the academicians on notice that ‘they were now to follow Party policy rather than to exercise scientific leadership’.15 The trap was set for Vavilov. A coordinated campaign against his leadership of the Genetics Institute was launched by Stalin himself in May 1938, repudiating ‘the high priests of science [who had] retired into their shells’ and demanding an effort ‘to smash old traditions, norms and viewpoints’.16 A Pravda editorial called on the Academy of Sciences to oversee the restructuring of recalcitrant institutes; the presidium of the academy made an immediate start and singled out the Genetics Institute for failing to combat hostile class viewpoints on the biology front, and for refusing to acknowledge T.D. Lysenko’s works. Lysenko was invited to supervise research at the institute and installed a number of his acolytes. Vavilov was subjected to public humiliation at every opportunity by Lysenko, and his political deviations were minutely recorded by Beria’s NKVD [forerunners of the KGB]. With a growing sense of doom, Vavilov courageously remained true to his principles. He told a meeting of scientific workers in Leningrad in the spring of 1939:

  We shall go to the pyre, we shall burn, but we shall not retreat from our convictions. I tell you, in all frankness, that I believed and still believe and insist on what I think is right, and not only believe – because taking things on faith in science is nonsense – but also say what I know on the basis of wide experience. This is a fact, and to retreat from it simply because some occupying high posts desire it, is impossible.17

  He continued to point out the fallacies of Lysenko’s theories, and in the summer of 1940 signed a public statement on how Lysenko’s dismissal of plant hybridization was invalidated by the success of American breeders in improving their corn harvest by just such methods. This protest may have been the final trigger to Vavilov’s arrest on 6th August. Vavilov was tortured by his NKVD interrogator in the Lubyanka prison and eventually signed a false confession. Normally this would be swiftly followed by a summary trial and execution, but for reasons unknown, the process in Vavilov’s case was delayed. With pencil and paper, he used the time to write a book on the history of the development of agriculture, until his trial took place nearly a year after his arrest. He was charged with treason, espionage for Britain, and counterrevolution, all of which he denied at the five-minute tribunal hearing. He was sentenced to death by firing squad, but after appeals, this was reduced to twenty years in prison. All this took place against a background of chaos as the German army approached Moscow. Vavilov was transferred to Saratov jail on the banks of the Volga River, where he died of inanition in January 1943.

  Whether he ever knew it or not, Vavilov was elected a foreign member of the Royal Society in 1942. Some of the British scientists who were allowed to travel to Moscow in June 1945 for the celebrations at the Academy of Science, asked after him. By November of that year, the fact of his death, but not the circumstances, was known in London; repeated inquiries from the Royal Society to the Soviet Academy asking about the date and place of his death brought no response. In 1948, Sir Henry
Dale, the President of the Royal Society, felt compelled to resign from the Soviet Academy in protest (as did Hermann Muller). Both men decried the sham and obscure doctrine of Lysenkoism that was driving out the sciences of evolution and genetics in the USSR. As Dale wrote:

  This is not the result of an honest and open conflict of scientific opinions; Lysenko’s own claims and statements make it clear that his dogma has been established and enforced by the Central Committee of the Communist Party, as conforming to the political philosophy of Marx and Lenin… Since Galileo was driven by threats to his historic denial, there have been many attempts to suppress or to mutilate scientific truth in the interests of some extraneous creed, but none has had a lasting success; Hitler’s was the most recent failure. Believing, Mr President, that you and your colleagues must be acting under a like coercion, I can only offer you my respectful sympathy. For my own part, being free to choose, I believe that I should do disservice even to my scientific colleagues in the U.S.S.R., if I were to retain an association in which I might appear to condone the actions by which your Academy, under whatever compulsion, is now responsible for such a terrible injury to the freedom and integrity of Science.18