J.B.S. Haldane


John Burdon Sanderson Haldane, FRS [1892-1964] was one of the three main founders of modern population genetics, along with Sir Ronald Fisher and Sewall Wright.

In his life he played many parts: biochemist, physiologist, geneticist, soldier, popularizer of science, and spy. On occasion, he was even a fictional character.

Son of Britain’s most prominent physiologist, (John Scott Haldane, another eccentric polymath) he worked in his father’s lab by age 8 and was already acting as a human guinea pig. He attended the Dragon School, Eton (which he hated) and Oxford, which he loved. He mastered Latin, Greek, French and German and received a double first in mathematics and classics, although his interest was already turning to science. He was fascinated by the newly rediscovered Mendelian theory of genetics and made a significant discovery before graduation – genetic linkage, which occurs when different alleles are inherited jointly because of their proximity on the same chromosome. He discovered this by analyzing his younger sister Naomi’s guinea-pig colony. That early work was interrupted by the First World War, in which he served as an officer of the Black Watch – a Scottish regiment known by the Germans as the “Ladies from Hell”, because of their kilted ferocity. JBS Haldane in no way detracted from the regiment’s reputation: he was often in combat and actually enjoyed it. In fact he reveled in killing the enemy, personally delivering bombs behind enemy lines. His commander called him the “bravest and dirtiest officer in my Army.”

After service in France and Iraq, with occasional time outs for recovery from wounds and experiments in which his father exposed him to chlorine gas in order to test new gas masks, he resumed his research work, first as a fellow at Oxford and then accepting a Readership in Biochemistry at Cambridge where he taught until 1932. During that time at Cambridge he did most of his systematic work on evolutionary genetics. He was the first to estimate the mutation rate of a human gene and introduced the concept of genetic load, the net effect of the substandard genes in a population.

In 1927, he showed that the chance of fixation – reaching 100% frequency – of a single copy of an advantageous allele with advantage s is 2s. This key insight explains why a very limited amount of hybridization with another species is bound to result in the acquisition of most of their favorable alleles, and also plays a role in our analysis of the recent acceleration of human evolution. The work of this period is summed up in his classic The Causes of Evolution.

Of course helping to found the central theory of biology could not fully occupy his time. He made major contributions to enzyme chemistry. He acquired a wife, not without some trouble and strife, since she (Charlotte Burghes) was inconveniently married to someone else at the time. He was the first to suggest the possibility of ‘test-tube babies’ and the currently fashionable ‘hydrogen economy’. His famous essay “On Being the Right Size” elegantly shows how size itself (through the square-cube law) determines fundamental biological features.

His speculative writings such as Daedalus inspired works of science fiction, in particular Aldous Huxley’s Brave New World and Olaf Stapledon’s Last and First Men. He even shows up as the villain: Weston, in C. S. Lewis’s interplanetary trilogy, is thought to be modeled (in part) on Haldane.


In 1933 he became professor of genetics at University College, London. Naturally, since he was now a professional geneticist, he spent more and more time on other subjects. He did important work in chemical genetics, which served as a foundation for modern biochemical genetics. He spent much of his efforts on the popularization of science, writing hundreds of essays. This included almost 400 essays in the Daily Worker, the publication of the Communist Party – no coincidence, as Pravda used to say. He had become a Socialist during his time in the trenches and had drifted left over the years, eventually joining the Party and becoming a member of the Daily Worker’s editorial board. Party loyalty resulted in ridiculous attempts at defending Lysenko’s genetic theories about the inheritance of acquired characteristics, which he of course knew to be nonsense.

During the World War II, his war work involved experiments (including experiments on himself, as usual) at high atmospheric pressure aimed at protecting submariners, a continuation of his and his father’s work in the physiology of respiration. At the same time he appears to have been an active Soviet agent (code name Intelligensia), judging from the Venona decryptions of coded Soviet messages. This is by no means surprising: Haldane, born without fear, always acted on his beliefs. Unfortunately, as Mahanti says, although in science he was the most open-minded of men, in politics he was dogmatism incarnate.

His first wife broke with Communism around this time after visiting the Soviet Union and learning far too much about it; their divorce soon followed, and he married Helen Spurway, a young geneticist who shared his political delusions.

Fortunately for the progress of science, the authorities did not become aware of his treason during his lifetime. He continued to do important work: in 1948 he came up with the idea that sickle-cell anemia and other hereditary disorders of red cells were most likely an evolutionary response to malaria – more generally, that infectious disease must have been a potent influence on human evolution. Those fertile ideas have since been abundantly confirmed – we have a few things to say on that topic later in this book.

Also in 1948, Lysenko managed to have Mendelian genetics banned in the Soviet Union, something which even Haldane could not swallow (although he had managed to tolerate the death by starvation in the Gulag of his colleague Vavilov). This led him to leave the Communist Party in 1950 and stop his endless blathering about dialectical materialism – although as late as 1962, he still thought of Stalin as “a very great man who did a very good job.” You know, like Tamerlane.

One of his most important achievements in later life was training and inspiring his graduate student John Maynard Smith, who became one of the most prominent biologists of the last half of the 20th century. He’s said to have told Maynard Smith that he would lay down his life for two brothers or eight cousins, anticipating the theory of kin selection.

He spent the last years of his life in India, claiming that he had left Great Britain because of the Suez crisis, but actually motivated more by a general distaste for the Establishment and by interest in India’s flora and fauna. In that period he wrote a famous, influential, and wrong paper on the ‘cost of natural selection’, concluding that one substitution every three hundred generations was the maximum possible rate of evolution: as it turns out, the human race over the past few thousand years has been evolving at roughly one hundred times that maximum rate. In India, Haldane found it impossible to get along with any kind of authority or administration, as had been the case for all his life: this limited his success there.

He contracted colon cancer in 1963, at the age of 72, and died on December 1, 1964.

We think that people have underestimated the importance of Haldane’s work for several reasons. The first is that his work had such breadth that few non-polymaths could fully appreciate or evaluate it. The second is that he was an intensely annoying person. For example, in his work on respiration he learned how to speak while inhaling as while exhaling – while allowed him to speak continuously. More than that, we think that his contemporaries were irritated by the way in which he wasted his talent. Although he was “probably the most erudite biologist of his generation, and perhaps of the century” (White 1965), legendary for his memory and originality, he would spend his time on politics, on endless petty rebellions against every kind of authority, and worst of all on science popularization. And yet he still accomplished more than they did – what could be more irritating than that?