The Man who Invented the Chromosome: a Life of Cyril Darlington
Oren Solomon Harman (Harvard University Press, 2004)
Reviewed by Gavan Tredoux
This is the first full-length biography of the once well-known and widely-read geneticist Cyril Dean Darlington (1903-1981). The only other substantial source is a notice in the Biographical Memoirs of Fellows of the Royal Society (Lewis, 1983), but Harman has not taken his opportunity; he fails to engage convincingly with Darlington’s rich intellectual life, which extended from differential psychology to race and universal history, far beyond the chromosomes he made his name in. The author is also guilty of plagiarism.
Darlington’s early career was undistinguished. From a family of modest means and accomplishments (his father was a schoolmaster and later a secretary to a chemist), he showed little promise at school. Unhappy and isolated, he preferred to read omnivorously on his own, something he kept up throughout his life. The family atmosphere appears to have been on the cold side of reserved. An elder brother served in the Great War, but Cyril did not have much to do with him. His own higher education started at an agricultural college, but an application to farm cotton abroad was turned down. Perhaps Darlington would never have been noticed if he had not, after reading Morgan and Sturtevant’s Physical Basis of Heredity (1921), persuaded William Bateson to take him on as an unpaid researcher at the John Innes Agricultural Institute. Relegated at first to routine and menial tasks, he rose surely through the ranks. The Innes Institute was then the leading genetics center in Britain, even if its leader Bateson had fallen out of touch with his rapidly developing field.
His initial shyness overcome, Darlington was strikingly attractive as a young man; tall, fair and athletic. “A cross between a cavalry officer and a film star”, Lewis (1983) reports, and the photographs bear this out. He was a womanizer at first, concocting a short-lived sham marriage while on a trip to America, simply to annoy his conventional parents, and engaging in a string of affairs with colleagues and associates. His two subsequent marriages were conducted in Scotland, under the informal arrangements popular at the time with elopers; the looseness of a Scottish marriage suited his needs. The first of these was to a geneticist, who collaborated professionally with him but was prone to severe depression. Although the marriage produced several children, Darlington abruptly got rid of her, moving in with another of his co-workers. For a while he refused to pay support to his abandoned family. The second was, as far as one can tell, faithful and happy. However, his previous wife had madness in her family and two of Darlington’s children by her ultimately committed suicide: his son, a promising geneticist, while Darlington was still alive; a daughter, some years after his death.
The field Darlington first made his name in - cytology, or the study of organic cell structure - is not readily accessible to most readers. The early history of controversies in the field, played out in the first half of the 20th century, might be arcane even to a present-day cytologist (working scientists, for the most part, do not spend much time looking backward). Harman’s lengthy coverage of the maze of false leads, abandoned hypotheses, misunderstood observations and minor feuds, will glaze many eyes. Although he does manage to convey some sense of the importance of Darlington’s contributions to cytology (his groundbreaking study, Recent Advances in Cytology, first appeared in 1932), few of Harman’s lay readers will understand exactly what these were, since he makes no real effort to broaden his audience. Most importantly, Darlington established just how it is that chromosomes recombine to establish the linkage between genetics and heredity; but he was also an expert and widely-read popularizer of science, and his own Genetics and Man (1964, first published as The Facts of Life in 1953) is a better place to start.
Scientifically, Darlington was a synthesizer, constructing systems and unifying theories with a view to explaining broad bodies of observations; he favored bold hypotheses, which he was equally prepared to reject if the evidence required it. He was not a patient and cautious observer - unlike many of his colleagues, who built up facts and exceptional cases for decades, and were often upset by Darlington’s bold and sometimes risky generalizations, or so they said. He was not a mathematical biologist of the Haldane or Fisher variety, but rather an unusually literate biologist with a thorough grounding in plant genetics. Darlington’s idea of scientific procedure provoked a warm response from Karl Popper, because it reminded Popper of his own account of science as a series of “conjectures and refutations”, but Popper was not convinced that Darlington’s hereditarianism was “falsifiable”. Harman misses the crucial point, though, that Popper (1982) thought Darwinism was itself “unfalsifiable” because it was a tautology: the fittest survive, but those who survive are fit. Popper is said to have changed his mind about Darwinism later, provided it was phrased in terms he did not object to.
The key to Darlington’s theory of evolution, first set out in his influential study The Evolution of Genetic Systems (1939), was his notion of a “breeding system”. For Darlington it is the breeding system as a whole, rather than the individual bearers of genes, that selection operates on to produce evolution. By this Darlington meant not only the chromosome structure of an organism, but its whole approach to breeding:
It is .. not by acting directly on a single change in a gene or chromosome or on a single cell or a single individual that selection is constructive. … It is by acting indirectly on combinations of changes of many kinds through their effects which are of many kinds. … A large part of [evolutionary] effects concern the genetic system whose properties have nothing to do with the survival of the individual but only of its posterity. All adaptation of the genetic system is therefore pre-adaptation. Its has no relation to any existing environment. Its relations are internal to the species and often … extremely unstable and subject of their own evolutionary laws. … In the evolution of the genetic system all the primary types of variation interact and the genetic system itself reacts on the external form of the individual. (pages 225, 236-7)
In the case of man, this “genetic system” is complex, including stratification into races (breeding groups) and castes (ranked breeding groups with hereditary occupations). These breeding groups pursue varying strategies for inbreeding and outbreeding, depending on their circumstances, because there is a continual evolutionary tension between adaptation and variation. Inbreeding is a successful strategy for a group whose environment remains relatively static for some time, and inbred groups can achieve high levels of fertility, tending to eliminate internal genetic variation and thereby adapt to their environment. Outbreeding is suited to groups whose environment changes, because it produces increased variation. However, an inbred group that switches too rapidly to outbreeding reduces its fertility, whereas an outbred group that switches to inbreeding risks the combination of harmful recessive genes. Genes select their environment, which in turn selects them.
Director of the Innes Institute by 1939, and elected to the Royal Society in 1941, Darlington quickly established himself as a leading figure of his day, not only within the genetics field but also in the more general world of ideas. In 1947 he founded, with R. A. Fisher, the highly influential and financially successful journal Heredity (unusual because it did not use anonymous referees, selecting material editorially instead). When J.B.S. Haldane moved to India in 1957, striking a pose for Third-Worldism in response the Suez Crisis, Heredity became the premier British journal in its field. In 1953, Darlington moved from the Innes Institute to Magdalen College in Oxford, taking up the Sherardian Chair of Botany, his first academic appointment (and a rule-changing precedent, since he was not an Oxbridge product). He retired in 1971, but maintained his prolific output until his death in 1981, continuing to produce books, articles and numerous letters to the newspapers.
Above all, Darlington was a great expositor, and a perceptive and original historian of the study of heredity. This is displayed in his popular history of genetics, Genetics and Man (1964), but his highly original little book Darwin’s Place in History (1961), is only briefly and not very helpfully touched on by Harman. Darwin never completely let go of the inheritance of acquired characters - the Lamarckian account of evolution, or “soft heredity” - and subtly reintegrated this idea into the Origin of Species as it went through its many editions. In effect, Darlington argues, Darwin retreated from the “hard heredity” of natural selection, partly because he was unable to make his theory work with the evidence he had. Some of the trouble lay in Darwin’s blending idea of heredity, “pangenesis”. This entailed, as Fleeming Jenkin famously argued, that advantageous characters would simply vanish over time, diluted in later generations as inexorably as a homeopath’s dose of medicine. Evolution was rapidly accepted by the Victorian establishment precisely because the Natural Selection at its core, with all its uncomfortable implications, was fudged from hard heredity to soft heredity. Most of the sciences could continue more or less as they were, happily accepting but largely ignoring a theory of evolution that had its fangs removed:
… in the field of Darwin's own deepest inquiries, botany, zoology and geology, the universities have proved as resilient as the Churches. We expect that disciples will take some of the life out of teachings of any master. But in our universities it is not clear that Darwinism ever came to life. The acceptance of a theory of evolution was so long overdue that when it came it merely confirmed the established programme. Classification, dissection, and description could continue. The barnacles were not in the end unhonoured. (1961, pages 72-3)
Much of Darlington’s later career was devoted to an elaboration of evolutionary theory applied to man, anticipating the spirit of the sociobiologists who later followed. His wide-ranging interests had prepared him for this ever since adolescence, and the result was The Evolution of Man and Society (1969), a provocative universal history of man from a genetic perspective. This was history that took heredity seriously, perhaps the only substantial history ever successfully attempted from that perspective; to complete it, Darlington cast his net widely. The product owed a great deal, as Darlington acknowledged, to his early contact with J.B.S. Haldane, then a left-wing eugenicist and not yet a Marxist, at the John Innes Institute. There was also his friendship with Sir Cyril Burt, the eminent hereditarian psychologist; and his warm relationship with the distinguished biologist John Randal Baker, now remembered chiefly for his influential book on Race (1974). Typical of Darlington’s approach to man was his contention that “ideas do not fly on wings, they march on feet”. Throughout most of human history, ideas and technologies have not spread culturally but rather through the movements of those skilled in them, not merely by practice but also by heredity, an adaptation developed by selection over an extended period.
Darlington was perhaps the last major hereditarian to escape serious public controversy, though the academic reaction to his major work, The Evolution of Man and Society (1969), followed by The Little Universe of Man (1977), showed that he was already out of step politically with many of his colleagues. Soon Arthur Jensen, Richard Herrnstein, John Baker and (posthumously) Cyril Burt would be drawn into a political firefight over the role of genes in human nature. In the 1970s, the Science for Society movement completed the slow divorce of the International left from eugenics, a process that had started when Stalin banned eugenics in 1930, and intelligence testing in 1936. Today it is inconceivable that a major publishing house would even carry a book like The Evolution of Man and Society.
Harman suffers from the disadvantages imposed by a lack of sympathy for his subject, though this is not as strong a dislike as Ray Monk (1996) developed for Bertrand Russell, or Martin Stannard (1987) for Evelyn Waugh; and it may just be posturing. He gives short shrift to Darlington’s application of evolutionary ideas to man, tending to dismiss his subject as something of a relic and a fogey, out of touch not only with his science but with modern ideas as a whole, displaying a deplorable tendency to make controversial remarks and a regrettable lack of enthusiasm for Third World emigration to the UK. The descriptions given of Darlington’s ideas are often little more than caricatures. For instance, Darlington’s use of the phrase “genetic determination” is partly conflated by Harman with the quite different idea of “determinism”, a philosophical position that Darlington certainly did not subscribe to. Genetics and Man shows quite clearly that Darlington did not exclude non-genetic factors (misleadingly called “nurture” by many), and was aware that the interesting question is whether a difference in “nature” matters more to a difference in outcomes than a difference in “nurture”. Since man not only selects but also creates his environment, Darlington believed that heredity completely dominates environment in the real world, in a way that is not expressed adequately by the usual measures of heritability used by behavior geneticists.
It is also quite incorrect and unforgivably lazy of Harman to describe John Baker as a “typologist” and a “conservative reactionary” (a blunt term of abuse now that Mao and Lenin have had their way with it). Baker was a classical liberal who had been among the first to defend geneticists and biologists in the Soviet Union, raising the question of the great geneticist Nikolai Vavilov’s disappearance during the war (he had already perished in the Gulag as a Mendelist-Morganist anti-Soviet element). As Harman himself reports, Baker, along with Michael Polanyi, helped to found the Society For Freedom in Science in 1943, to publicize the destruction of genetics in the Soviet Union. This was a time when most of Baker’s contemporaries and colleagues, with the notable exception of Darlington himself and a few others, thought awkward questions might annoy the Soviets unnecessarily, harm the cause of International Socialism, or break communist party discipline (the case of J.B.S. Haldane and J. D. Bernal). As a result, Darlington and Baker aroused the interest of George Orwell. With Orwell’s help, Darlington played a major role in the exposure of Trofim Lysenko’s anti-genetic peasant science (see Soyfer, 1994). Nor was Baker a racial “typologist”, as even a cursory examination of Race (1974) would show. Races were for Baker, as they were for Darlington, breeding groups with lines drawn at whatever level of abstraction is desired.
Unfortunately, there are breaches of integrity in the text that cannot be ignored. Paragraphs have been reused, without attribution or reference, from a piece by myself (Tredoux, 2000): for examples, see pages 2 and 232-3. Harman has also plagiarized material from the biographical notice by Lewis (1983): see page 14 of Harman, and page 114 of Lewis. The text has noticeable irregularities of style in many other places. Harman had access to the Darlington papers held in the Bodleian library at Oxford, including the copious and reportedly frank personal diaries, not to mention the wealth of published material by his prolific subject. His challenge should have been what to leave out, not where to reach for things to put in.
Darlington, C. D.
1932. Recent Advances in Cytology. Churchill.
1939. The Evolution of Genetic Systems. Second edition, Basic Books, 1958.
1953. The Facts of Life. Allen and Unwin.
1961. Darwin’s Place in History. Macmillan.
1964. Genetics and Man. Allen and Unwin.
1969. The Evolution of Man and Society. Simon and Schuster.
1969. “The Genetics of Society.” Past and Present (No. 43, May): 3-33.
1977. The Little Universe of Man. Allen and Unwin.
2000. "Two geneticists: J.B.S. Haldane and Cyril Darlington", PINC. Mirrored from http://www.cycad.com/cgi-bin/pinc/apr2000/articles/tredoux-haldane-darlington.html