by Steve Jones
The ties between biology and the politics of difference that began before Hitler were not broken until many years after his death. Until 1913 the Statue of Liberty really did welcome, as its inscription says, the huddled masses, struggling to be free. In his 1916 book The Passing of the Great Race the euphonious American, Madison Grant, echoed many of his fellows when he complained that alien races were being grafted onto the nation's racial stock. With the advice of biologists, President Coolidge was moved to say that 'biological laws tell us that certain divergent peoples will not mix or blend. The Nordics propagate themselves successfully. With other races, the outcome shows deterioration on both sides.'
After determined genctical lobbying, the first Immigration Act was passed in 1924. It set limits to ensure that the ethnic composition of the USA stayed at what it had been in the late nineteenth century. Each country was allowed quota of two per cent of the numbers of its citizens present in the United States in 1890 (when most of that nation's people were from the British Isles, Scandinavia and Germany). The law was very good at keeping Eastern Europeans out and left many to the mercies of the other experiment in race hygiene which soon began there. It was not repealed until 1966. The theory of pure races had cast a long shadow. Its spectre has not yet disappeared. A Hungarian political party campaigned against rights for gypsies in the nineteen-nineties as they were 'a disadvan-taged group, to whom the laws of natural selection have not been applied.'
Genetics has at last provided the tools to test the pure race theory. The word 'race' itself is ill-defined. It includes social and political as well as biological criteria. In an attempt to escape a difficulty by renaming it the term 'ethnic group' is sometimes used. Such groups can define themselves. The Scots scarcely existed until they were invented by King George IV, who in i8zz visited Edinburgh and, dressed in a Stuart kilt and a pair of flesh-coloured tights, gave the Scots a national identity they never knew they possessed. It took only the imagination of Sir Walter Scott in devising a native culture to produce a new and potent myth. It was based on the kilt, which, as Macaulay said, 'before the Union, was considered by nine Scotchmen out of ten as the dress of a thief. The Celts, the larger unir to which the Scots claim allegiance, are themselves an illusion. Celtic culture, defined by artefacts excavated in southern Germany, was hijacked by the French and the Germans as well as the Celtic Fringe as a statement of national worth. In fact, trade had more to do with the spread of Celtic civilization than did sex or conquest.
For ethnic identity what matters is what group we think we belong to. For genes it is not so simple. Perhaps those that count are the ones most visible. After all, people do tend to choose mates of the same skin colour as themselves and this might be important when it comes to the nature of race. The theory of pure races made a definite claim about human groups; that they descended from a series of distinct ancestors. If this is so, and mere appearance represents the remnants of this history, then each race should be distinct in most genes and not just those for skin colour or hair form.
What does the genetic atlas look like? Are shifts in skin colour — the result of a dozen or so genes — matched by parallel trends in the tens of thousands of genes that build a man? The answer is, quite clearly, no.
Everyone can see global trends in colour, hair form and so on. Plenty of less obvious patterns exist but what is behind them is quite unknown. Some patterns are so obvious that they almost beg to be justified in selective terms. In England, the gene for blood group B is rare and is borne by fewer than one in ten people. In central Russia and in west Africa, in contrast, it is common, and up to a third of the population carry that variant. In the rhesus system a marriage between a positive man and a negative woman can be dangerous when the mother's blood reacts against that of her unborn child, but rhesus negative is common in Europe and Africa (albeit rare elsewhere). It must once have had some advantage that allowed it to spread in the face of this penalty.
Even the imaginative are pressed to explain some other trends in terms of selection. Most westerners have sticky ear wax, but that of most orientals is flaky and dry. And why can most Indians taste the bitter substance PROP while Africans cannot and what causes fingerprint patterns to vary so much across the world?
For none of these is there an explanation: but, as so mm. It ot modern medicine depends on genetics we have.irrived at the rather unexpected position of knowing more about the patterns of change in humans than in any other animal. Hundreds of functional genes and thousands of variants in the non-coding parts of DNA have been mapped. Most vary in frequency from place to place. The picture that emerges is quite different from that supported by those who believe mankind to be divided into distinct races. Man, it transpires, is the most boring of mammals, varying scarcely at all from place to place. The trends in physical appearance are not accompanied by those in other genes. Instead, the patterns of variation in each system are more or less independent. We would have a different view of race if we diagnosed it from blood groups, with an unlikely alliance between the Armenians and the Nigerians, who could despise the B-free people of Australia and Peru. Gene geography shows that people from different places do not differ much and that colour says little about what lies under the skin.
Imagine that the whole world could be measured for the diversity it contains. The job should be easy enough; after all, its people would all boil down into a soup which would just fill Windermere. The total set can be sorted out among individuals, countries and races to see how it splits up. The analysis, which is based on hundreds of genes in scores of populations, shows that around eight tenths of total diversity, worldwide, comes from the differences between the people of the same country: two Englishmen, say, or two Nigerians. Another five to ten per cent is due to the differences between nations; for example, the people of England and Spain, Nigeria and Kenya. The remainder — the overall genetic differences between 'races* (Africans and Europeans, for example) — is not much greater that between different countries within Europe or within Africa. DNA bears a simple message; that individuals are the repository of most variation. A race, as defined by skin colour, is no more an entity than is a nation, whose personality depends only on a brief shared history.
The notion that humanity is divided up into a series of distinct groups is wrong. The ancient private homeland in the Caucasus — the cradle of the white race — was a myth, as were its equivalents in Egypt or Peru. If, after a global disaster, just one group, the Albanians, the Papuans or the Senegalese, were to survive, most human diversity would be preserved. Humans are uniform creatures, because they evolved so recently. DNA sequence shows that the difference among the races is less than a fiftieth that between man and chimpanzee.
For other animals, race means more. The genetic differences between the snail populations of two adjacent Pyrenean valleys is far greater than that between Australian aboriginals and Europeans. For a snail it makes good biological sense to be a racist, but humans have to accept that they belong to a tediously homogenous species.
The fact that genes can be used to differentiate peoples {as skin colour does Africans and Europeans) is scarcely relevant to how different they are. After all, a forensic scientist can separate two brothers suspected of a crime with a blood sample, although the suspects share half their inheritance. Even a single gene may be a reliable indicator. If a bloodstain at the scene of a crime contains sickle-cell haemoglobin, it is almost certain that the suspect has African ancestry; but if it has the gene for cystic fibrosis {unknown among Africans) then the police should look for a Kuropean. Neither observation changes the fact that Africans and Europeans have most of their genes in common.
The issue of differentiability versus difference causes controversy in the legal profession. DNA fingerprints are enormously variable. Confident claims were made about how they would revolutionise forensic science. In one American court, the prosecution described the chance of error as one in seven hundred and thirty eight million million. A single trace of DNA
— blood, sperm, or even the saliva spat out onto the shirt of someone in close conversation with a supposed criminal — and the suspect would be identified. There was, it seemed, no room for argument. The case was so persuasive that sometimes judges even refused to hear evidence from the defence.
Now, life looks rather murkier. Of course, even if the test is infallible, the people who make it are not. There have been obvious lapses (such as mistakes in labelling samples). Other technical problems can also lead to difficulties.
The stained bands of the samples to be compared are lined up and compared by eye. The eye is an unreliable instrument, which gives plenty of room for error. Juries, typical as they are of the population as a whole, are bad at understanding risk (which is why the National Lottery does so well) and are much more likely to convict if told that the chance of a random match between defendant and sample is o.i per cent than the (identical) figure of one in a thousand. These arguments are the stuff of legal dispute and are no different from the controversies about other forensic tests that hit the headlines. However, forensic genetics faces a deeper problem that arises from evolutionary history.
DNA fingerprints are made up of short sequences of the message which are repeated again and again. The number of repeats and the position in which they occur varies from person to person. A sample from the scene of the crime is compared with one from the suspect and with others from a panel of innocent donors. Rather like an identity parade, witnesses pick out the criminal from a group known not to have committed the crime.
In the earliest days of ONA fingerprinting the FBI set up a reference group of donors made up of white police officers. To some jurors, if the suspect's fingerprint was more similar to that at the scene than to that of each member of the panel, the case seemed indisputable.
This simple approach faces an evolutionary problem. If an eyewitness had seen — say — a white man committing a crime, and then had to pick out the alleged criminal from an identity parade of blacks, legal eyebrows would be raised. The ethnic group of any suspect must be matched with that of the group with which he is compared.
DNA fingerprints evolve quickly. Those from people of African ancestry are somewhat different from those of Europeans (although the overall racial divergence for this character is not much greater than that for enzymes and blood groups, with nine-tenths of total diversity due to differences among individuals). Imagine a black suspect who is wrongly accused of a crime in fact committed by another black man. His DNA fingerprint is compared to that left at the scene and to those of a panel of whites. Genetic divergence between blacks and whites means that the innocent suspect's DNA may be more like that of the criminal than that of any European; and the innocent man is found guilty.
This has led to controversy in the world of DNA fingerprinting and it is right that it should. In the United States, where legalised murder by the state is common, the issue is one of life and death. The rule in American courts is that scientific evidence may be rejected if it is not generally accepted in the scientific community. Appeal courts threw out convictions for murder and rape because they are not satisfied that DNA fingerprinting is 'generally accepted*. Now, the scientists are ahead, with a survey of individual variation in DNA sequence so extensive that the small racial differences pale by comparison. Even so, the tale of' genetics and the law is another reminder that objective knowledge can soon be hijacked by those with a subjective view of how it should be used.
People from different parts of the world may differ but the idea of pure races is a myth. Much of the story of the genetics of race, a field promoted by some of the most eminent scientists of their day, was prejudice dressed up as science; a classic example of the way that biology should not be used to help us understand ourselves. Most of today's biologists feel that the moral issues raised by our own biology — racism, sexual stereotypes, and claims that selfishness, spite and nationalism are driven by genes — are issues of ethics rather than science and that science has nothing to do with how we perceive our fellows. Although it may comfort the liberal conscience to find that genetics reveals few differences among the peoples of the world, this is irrelevant to the issue of racism, which is a moral and political one.
As a result, those determined to dislike one race or another are not much impressed by scientific arguments. I once gave a lecture on race when I was teaching in Botswana. The class was delighted to learn that they were almost the same as the white South Africans who so despised them. At the end of the lecture there was just one question. Surely, a student asked, what you are saying can't be true of the Bushmen; they are obviously different from us.
I admit to a certain despair at that; but it was a useful reminder that although biology may tell us a lot about where we come from it says nothing about what we are. The dismal history of racial genetics strengthens that belief.
Chapter Fifteen EVOLUTION APPLIED
Evolution is now a practical subject in its own right although many who use it do not realise what they are doing. Inventors once used an approach close to that of the natural world. For gadgets and life, tinkering works; and can be the means to an unexpected end. Just like the engineers who designed stone tools or steam engines with no understanding of physics, the first farmers developed new crops with no knowledge of heredity at all. Pragmatism led, as always, to progress.
Nowadays, technicians in concrete or metal have a different attitude. They design what is needed with as much scientific theory as is necessary. Applied biology, from agriculture to medicine, has adopted this approach only in the last few years and has begun to advance as much as has transport since Stephenson's Rocket. For biology, a new steam age (albeit not yer a space age) is upon us.
A fusion of Mendelism and Darwinism has made agriculture much more productive. The amount of food available per head, worldwide, has gone up in the face of the greatest population explosion in history. In the developing world there is still room for progress as half of all crops are lost to weeds (a figure last seen in Europe in the Middle Ages) and disease can lead to the loss of entire harvests. In Africa, indeed, such is the rate of population growth that — against the world trend — the amount of food produced per person is decreasing. Third-world fanning has a long way to go before it catches up. General economic weakness is much to blame, but some of its failure is because it lacks the technology used elsewhere.
Darwin or Mendel would each feel quite at home with most modern agricultural research. In Illinois in 1904 an experiment started in which, each generation, the maize plants most rich in oil were bred from. The work still goes on and, a hundred generations later, the amount of oil has gone up by a hundred times with no sign of any slowing of progress.
Such straightforward applied evolution can do remarkable things, as any cattle-breeder can attest. The 'Green Revolution' took a step further down the genetic road. Its success came from crosses between new and productive stocks of rice and wheat, bred in the Darwinian way, and other lines with stiffer and shorter stalks. Just a few genes were involved. Dwarf varieties were crossed with others with rigid stems. Their descendants were mated with stocks that contained genes for high yield and rapid growth. Plants which combined the best qualities of their parents were chosen and the process continued for several generations. Sex — genetic recombination — did the farmers* job by making new mixtures of genes. It solved a major problem of tropical agriculture, the tendency of rice and wheat to grow tall when fertiliser is used, but to fall over in high winds. One simple trick transformed the rural economies of India and China. In fifty years, planned gene exchange gave a six-fold boost in yield, a figure as great as that at the origin of farming ten thousand years before.
Another refinement of Darwinism involves an increase in the flow of raw material upon which it feeds. To damage DNA can produce new genes ready for use by an alert technologist. Penicillin once depended on tiny amounts of antibiotic made in vast vats of fungus. Breeding from the most productive strains gave a hundredfold increase.
The next step did much more: mutations caused by radiation and chemicals led to a new generation of antibiotics, never seen in nature.
An even better way to renew the fuel for selection is to import genes from other species. One of the successes was the new crop triticale, a hybrid between wheat and rye. It can grow in dry places and is of benefit to agriculture in places (such as the American Great Plains) low in rainfall. It demonstrates the gains to be made by even a modest investment in moving genes between species. Another approach is to turn to a domestic plant's untamed relatives, as has been done with wheat itself by crossing with wild grasses that contain genes of value on the farm.
The standard agricultural approach of breeding from the best — evolution writ large — has limits, which are soon reached. Many crops and farm animals can evolve no further because they have used up their genetic reserves and have no source from which to replenish them. The constraint is set by sex: by the fact that to make creatures with new mixtures of genes their parents must mate. In spite of occasional lapses in the plant world, there are strict biological controls as to who mates with whom. The partners must be of different sexes but the same species. A few modest exceptions — triticale being one — are allowed: but to recombine genes, in nature or on the farm, sex is unavoidable. That law much decreased the ambitions of evolutionary engineers because genes that might be useful in improving one form are locked away within another.