FINGERPRINTING was invented in Bengal, during the Victorian Raj, by British army officers who wanted a sure fire way to tell their colonial subjects apart. Excited by the discovery that fingerprints were a reliable way of identifying individuals, the father of modern eugenics, Francis Galton, hoped to prove they would also reveal an individual’s “race”. He and his colleagues pored over thousands of fingerprints taken from people variously categorised as English, Welsh, Jews, Negroes and Basques. By 1892, however, he had to admit defeat: there were no systematic differences in fingerprints among any of the groups.
A century on, researchers have resumed the hunt. This time, however, the fingerprints they are poring over are genetic – and this time they might not admit defeat so readily. Emboldened by the impact DNA fingerprints have made already on forensic science, geneticists are looking for “signatures” in human DNA that could help forensic teams to make a good guess at a suspect’s skin colour and facial features. At the moment, DNA tests come into play only after suspects have been arrested, as an aid to establishing their guilt or innocence. But if the forensic geneticists looking for the new DNA signatures have their way, forensic teams could soon be predicting the “racial” origins of suspects well before anyone is arrested.
That, needless to say, will be about as welcome in many quarters as Galton’s ideas about race and eugenics. The question critics will ask is not just how accurate such tests would be, but whether the whole notion makes any sense scientifically when the little human genetic diversity that exists is fairly evenly distributed throughout the species.
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There are other, political worries too. In an age of “ethnic cleansing” and resurgent nationalism, wouldn’t any kind of DNA test for “race” – even one based on the tiny fraction of human genes that do vary with skin colour and other visible “racial” or “ethnic” characteristics – create more problems than it solved?
Naturally enough, proponents talk up the social benefits of developing such tests. Imagine, for instance, if forensic scientists could issue “Photofits” of suspects based on samples of blood, semen or hair taken from the scenes of crimes. It’s not as farfetched as it sounds. Such Photofits would require detailed information about the genes that influence the visible markers of “race” – hair colour, eye colour, skin colour, facial features and stature. And in time, some of that information is sure to emerge from international efforts to map and sequence the human genome.
Only skin deep
Take human skin colour, for example, which varies in a continuum through every possible shade. It seems to be influenced by three or four gene pairs that work together, in an incremental or “additive” fashion. Even so, genetic differences probably account for only some 70 or 80 per cent of the variation in colour, says Ashley Robins of the University of Cape Town in South Africa and author of Biological Perspectives on Human Pigmentation. “Skin colour is a complex phenomenon,” he says. We usually think of it as entirely determined by genetics, but at least 20 per cent of the variation is caused by environmental factors such as nutrition, hormones and lifelong exposure to sunlight. The same is true, he says, of eye and hair colour.
So even with some of the relevant gene sequences to hand, creating Photofits of suspects would be far from trivial. Most human physical characteristics depend not on one but several genes, and working out which genes influence which characteristic (and by how much) would require what Alec Jeffreys, a geneticist at the University of Leicester, who invented DNA fingerprinting in 1985, describes as a “profound revolution” in molecular genetics. “Indeed,” he says, “such DNA analyses may eventually prove in practice to be impossible.
But cruder tests that give probabilistic predictions are already going ahead. These are based on stretches of DNA that have nothing to do with skin colour or facial features. Walter Bodmer, director of the Imperial Cancer Research Fund in London, predicts that within a few years, forensic scientists analysing a sample taken from the scene of a crime will be able to say that “there is a fifty times higher than average chance that the person is a Bengali, or a Welshman, or whatever”. Indeed, the prototypes of such DNA tests for “race” already exist.
In 1993, a British forensic scientist published what is perhaps the first DNA test explicitly acknowledged to provide “intelligence information” along “ethnic” lines for “investigators of unsolved crimes”. Ian Evett, now at the Home Office’s forensic science laboratory in Birmingham, and his colleagues in the Metropolitan Police, claim that their DNA test can distinguish between “Caucasians” and “Afro-Caribbeans” in 85 per cent of cases. Evett’s test, published in the Journal of the Forensic Science Society, draws on apparent genetic differences in three sections of human DNA (This Week, 23 January 1993). Like most stretches of human DNA used for forensic typing, each of these three regions differs widely from person to person irrespective of race. But by looking at all three, say the researchers, it is possible to estimate the probability that someone belongs to a particular racial group.
At best, however, this type of test will only ever be able to produce rough predictions about “Bengalis” versus “Welshmen”. The DNA signatures they depend on are never found exclusively in one particular racial group. What does vary from group to group is the frequency with which such signatures occur. And even then there are no sharp divisions between racial groups that could be interpreted as marking DNA boundaries – just gradual and continuous shifts in the frequencies of certain signatures. Analyses of proteins found in blood tell the same story. Neither blood proteins nor the genes that encode those proteins define boundaries between “racial” groups. Instead, all these molecular markers reveal are continuous gradations in gene frequencies.
Just an illusion
In short, the notion of homogeneous, well-defined racial types is illusory, the product of cultural categorisations allied with small packages of mostly unidentified genes that evolved to adapt skin, hair and facial features to local climatic conditions. Such genes, according to Jonathan Kingdon, an evolutionary biologist at the University of Oxford, “give superficial similarity to people who are actually of very diverse origins”. All this, however, may readily be lost from view if DNA tests designed to give probabilistic predictions of physical appearance bolster popular belief that it is scientifically sound to test for racial types. As a result of molecular biology “race will regain a new legitimacy”, fears Paul Rabinow, an anthropologist at the University of California at Berkeley. Genetic data will seem more real, more definitive, than the old cultural classifications.
To develop even crude DNA tests for “race”, geneticists need samples of DNA from many individuals from many different populations. But law enforcers are eager to help. Earlier this year, Britain’s police force set up the world’s first national DNA database. In the crime-torn US, law enforcement agencies in more than 20 states have established forensic DNA databanks. And a nationwide computerised network called CODIS, or Combined DNA Identification System, is now coming online. Designed to link regional DNA forensic centres, CODIS is being set up by the FBI.
Body of evidence
Another rich source of material for what is sometimes called “forensic anthropology” is the human genome project – particularly its recently launched offshoot, known as the Human Genome Diversity Project. èƵs working on this international collaboration intend to collect DNA samples from more than 400 isolated ethnic groups scattered throughout the world (see “Genes from a disappearing world”, èƵ, 29 May 1993). They will focus on ones likely to be the most distinctive in genetic terms: isolated populations with distinct cultures and languages which are under threat of extinction. Already, cell lines containing the genetic material of the Baika pygmies of Central Africa and the hill people of New Guinea thrive in a laboratory at Yale University.
In analysing such genetic material, researchers will focus on DNA regions known to vary the most from individual to individual. The DNA of two genetically unrelated individuals is estimated to be between 99.7 and 99.9 per cent alike in the sequence of base pairs that make up the alphabet of the genetic code. But even this scant difference means that any comparison of 1000 base pairs along any particular DNA molecule may turn up between one and three differences. Because most genes are longer than 1000 bases, there may be several genetic differences from person to person in nearly all the 60 000 to 70 000 genes people are now thought to possess.
The vast majority of these differences will be “neutral” or will appear in noncoding sequences – “silent” regions of DNA that do not produce any protein product – and so will not produce any physical effect. Yet among this wealth of variation, new correlations will be found that may appear to bolster the legitimacy of racial categories.
One family of genes already under scrutiny are the so-called HLA genes of the immune system. These genes are responsible for the rejection of unmatched organ transplants and are a rich source of variation: the frequency of one particular variant of an HLA gene has been found to range from 0.2 per cent in a Japanese population to 19 per cent in a group of French whites, for instance. Another is said to be a “high-frequency Chinese marker found in nearly 50 per cent of Cantonese”.
“Junk” DNA – sequences that do not code for any protein – may be even more informative. One such family of variable sequences – which differ widely from person to person, for no apparent reason – are known as VNTRs, or “variable number of tandem repeats”. As long ago as 1988, these DNA sequences have been pursued by geneticists as signposts for both disease genes and potential markers of “racial” origin.
Of all such DNA “polymorphisms”, the ones most useful for making racial distinctions will be those that are “population specific”, or “private”, according to Adrian Hill, a molecular geneticist at the Institute of Molecular Medicine in Oxford. While this hasn’t been true of most DNA polymorphisms described to date, says Hill, “sufficient private polymorphisms are turning up to indicate that the genome as a whole must contain large numbers of population-specific variants”. Hill also believes that it should be easiest to use DNA polymorphisms to identify African ancestry, since people of African origin seem to have a disproportionate number of “private” polymorphisms.
Forensic tests will not be the only application of such genetic data. Indeed, assessments of human genetic variation may come to have greater political implications outside the criminal justice system. Consider the furore in the US over who qualifies as a “Native American”. Access to land and social services, as well as considerable social cachet in some circles, now accrues to those who are considered to be descendants of the original inhabitants of what is now the US. But who qualifies as a “real” American Indian?
Blood ties
The US government has long “certified” the identities of Native Americans on the basis of “blood quantum”. When first introduced in the Allotment Act of 1887, these criteria denied land rights to those who were less than “half-blood”, enabling the federal authorities to appropriate millions of acres of “surplus” land for the use of “white” settlers. The continued use of blood quantum criteria by the Bureau of Indian Affairs – now set at “one-quarter blood” – has led to conflicts among Indian peoples competing for benefits tied to federal recognition. It has also forced many tribes to adopt similar racialised “membership” policies themselves, overturning traditional ways of creating new kinship ties through intermarriage, adoption or naturalisation.
The US government’s policy of requiring American Indians to produce official “Certificates with Degree of Indian Blood” has also forged alliances across tribal boundaries, and some groups have begun to band together to oppose federal policies and to claim the right of self-determination. In 1985, one woman successfully sued the Bureau of Indian Affairs for denying her federal benefits because she was “less than quarter blood”. But this legal precedent has so far failed to move federal authorities to abandon their blood quantum criteria.
Political debate surrounding Indian identity has now intensified, in the wake of the Indian Arts and Crafts Act of 1990. This law makes it a crime to publicly identify oneself as American Indian when selling artwork, or for a gallery to exhibit art as “Indian”, if the artist cannot provide federal certification.
“Since the passage of the bill, mediocre but certified ‘Indian’ artists have started denouncing non-federally certified Indian artists whom they perceive as competitors,” says Annette Jaimes at the University of Colorado. She claims that the implications of the arts and crafts bill go far beyond the Indian art market. “The self-ordained Indian identity police have begun to spread rumours and spurious allegations on university campuses and in other institutions about persons whom they claim are impostors ‘masquerading as real Indians’.” Those on their hit list are accused of “ethnic fraud”, says Jaimes, with job opportunities, professional credibility and personal integrity under threat.
Political minefield
Into this political minefield may come genetic data on the frequencies of particular genetic sequences in those who claim to be North American Indians. The result could be new criteria for including and excluding individuals as “real” American Indians – new ways of deciding who “belongs” within that categorisation and who does not. The fact that any such genetic test would necessarily be arbitrary – based on the possession of a limited number of genes chosen on a statistical basis as “characteristic” of Native Americans as a whole – might not lessen its appeal to federal authorities, and to some members of the North American Indian community as well. Already, geneticists in Ottawa have attempted to distinguish between “Caucasian” Americans and Native Americans on the basis of a variable DNA region often used in DNA fingerprinting.
Will the same sorry tale be repeated across the globe when the “human genome” is an open book and we can all read our ancestral origins in our genes? Few contemporary commentators doubt that the fruits of the human genome project will, in time, radically restructure our perception of what and who we are. It’s easy to imagine molecular biology both destabilising existing boundaries between races and defining new ones, perhaps creating new hierarchies based on “superior” and “inferior” genes in the process. Easy too to imagine that data on genetic variation might one day become a novel tool of repression in regimes intent on genocide or “ethnic cleansing”.
Yet, used in a different way, data from the human genome project could enhance our understanding of what it is to be “European” or “British”, “white” or “black”. They could even encourage us to begin celebrating our genetic inter-mingling. This is what Salman Rushdie, who describes his novel The Satanic Verses as “a love-song to our mongrel selves”, urges us to do. After all, says Rushdie: “Mélange, hotchpotch, a bit of this and a bit of that is how newness enters the world.”