WDC Spring Guest Buffet - ‘Nature, nurture or neither? The view from the genes’

Steve Jones

This well-attended event was held in the Old Refectory on 6 March 2013.

We were delighted to welcome Professor Steve Jones, Emeritus Professor of Genetics, UCL, who spoke to us at the end of a very busy day in which he had given several similar talks to highlight his forthcoming book. Steve described The Serpent’s Promise (due out on 2 May) as a re-write of the Bible written as if it were science. The first slide showed a bronze statue of a chimpanzee sitting on a pile of books, including one by Darwin and another with a page displaying the phrase “Eritis sicut deus” (and ye shall be as God), from Genesis when the serpent is enticing Eve to eat from the Tree of Knowledge. This statue by Hugo Reinhold was first exhibited in 1893 at the Great Berlin Exhibition and one can be found in the Institute for Evolutionary Biology at Edinburgh University, where Steve was an undergraduate and postgraduate student.

He then produced some interesting statistics. In Shakespeare’s time only one in three children survived to the age of 20, now it is 99% in the UK. However, two of every three of us will die from a cause related to our genes. Returning to Shakespeare, Steve mentioned The Tempest, where Caliban illustrates the dilemma of whether nature or nurture was responsible for his character and behaviour. This is a false dichotomy, but even in the recent past it was believed that criminal tendencies could have a genetic basis.

We were reminded of Francis Galton, Darwin’s cousin and a genius in the study of heredity, who in 1911 left money to fund a Chair of Eugenics at UCL. The eugenics movement developed from a belief that those with genius had fewer children and that it might be possible to breed humans for desirable characteristics. Several important genetic studies were carried out, but some would fail to get ethical approval today. For example, in Sweden during the 1950s, boys guilty of shoplifting were castrated so that their supposed genes for criminal tendencies could not be passed to subsequent generations.

Steve then gave us some examples in which the importance of particular genes has been well established. For example, in the genetics of cats Darwin commented that all blue-eyed white cats are deaf. In Siamese cats, the coat colour is determined by a gene for melanin, which is differentially expressed according to the external temperature. Cool parts are black (such as feet and end of tail) whilst warmer regions are white. This is a good example of a combination of genetic and environmental factors. Turning to humans, Steve described Mo Farrar, the Olympic runner, with his identical twin who is a farmer in Somalia. They have the same genes but were brought up in very different environments and took part in different levels of physical activity. In both dogs and horses, there are gene duplications or slight changes in DNA sequence (polymorphisms) that can influence speed and ability to sprint or to run long distances.

Returning to his own education, Steve described the eleven-plus examination as a so-called genetic test of inborn ability. Only one in ten children passed and, having looked at past questions, he thought the exam was complete rubbish. Twin studies have shown that genetic variation in IQ is very subtle and most differences are due to poverty and nurture. Returning to Galton’s belief in genes related to criminal tendencies, Steve referred to the Kallikak family. They were the subject of a book, A Study in the Heredity of Feeble-Mindedness’ published in 1912, that appears to present a family tree showing inherited feeblemindedness. Other possible causes were infections such as syphilis or tuberculosis, although Steve thought there was a bit of truth in the idea of a genetic link.

Finally, Steve described the genetic evidence for antisocial behaviour in men who have a particular sex-linked genetic mutation that influences the enzyme monoamine oxidase. This results in an inability to control emotions. In a case tried in Georgia, USA, a murderer of at least five people argued that he should not face the death penalty because he had this particular mutation. He had two trials and this defence led to a 10-year delay in his execution. A considerable argument followed as to whether someone with a ‘bad gene’ should face execution. George W Bush, then governor of Texas, decided that this was no excuse.

After this fascinating talk, Steve was warmly applauded and formally thanked on our behalf by his former colleague, Dr Frances Lefford.

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