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Scientists Decry "Flawed" and "Horrifying" Nationality Tests
29 September 2009 9:57 am
(This story is adapted from a version appearing in this week's Science)
CAMBRIDGE, UNITED KINGDOM—Scientists are greeting with surprise and dismay a project to use DNA and isotope analysis of tissue from asylum seekers to evaluate their nationality and help decide who can enter the United Kingdom. “Horrifying,” “naïve,” and “flawed” are among the adjectives geneticists and isotope specialists have used to describe the “Human Provenance pilot project,” launched quietly in mid-September by the U.K. Border Agency. Their consensus: The project is not scientifically valid--or even sensible.
“My first reaction is this is wildly premature, even ignoring the moral and ethical aspects,” says Alec Jeffreys of the University of Leicester, who pioneered human DNA fingerprinting.
U.K. immigration policies have been under scrutiny recently as the number of people claiming asylum has soared and as French police in Calais last week cleared a camp of migrants hoping to make it across the English Channel. The existence of a DNA-based program to identify nationality was recently revealed by the Daily Mail and The Observer, sparking protests from refugee advocates. Science has obtained Border Agency documents showing that isotope analyses of hair and nail samples will also be conducted “to help identify a person’s true country of origin.” The project “is regrettable,” says Caroline Slocock, chief executive of Refugee and Migrant Justice headquartered in London. Although asylum-seekers are asked to provide tissue samples voluntarily, turning down a government request for tissue could be misinterpreted, she says, “so we believe [the program] should not be introduced at all."
The Border Agency’s DNA-testing plans would use mouth swabs for mitochondrial DNA and Y chromosome testing, as well as analyses of subtle genetic variations called single-nucleotide polymorphisms (SNPs). One goal of the project is to determine whether asylum-seekers claiming to be from Somalia and fleeing persecution are actually from another African country such as Kenya. If successful, the Border Agency suggests its pilot project could be extended to confirming other nationalities. Yet scientists say the Border Agency’s goals confuse ancestry or ethnicity with nationality. David Balding, a population geneticist at Imperial College London, notes that “genes don’t respect national borders, as many legitimate citizens are migrants or direct descendants of migrants, and many national borders split ethnic groups.”
After reviewing the Border Agency’s plans, Jeffreys echoed those criticisms in an e-mail to Science: “The Borders Agency is clearly making huge and unwarranted assumptions about population structure in Africa; the extensive research needed to determine population structure and the ability or otherwise of DNA to pinpoint ethnic origin in this region simply has not been done. Even if it did work (which I doubt), assigning a person to a population does not establish nationality - people move! The whole proposal is naive and scientifically flawed.”
Another geneticist says the Forensic Science Service, a former government agency that has been privatized, requested his opinion earlier this year on how to develop a genetic assay to distinguish among East African populations. “I thought it was for forensic purposes, not border control,” says Christopher Phillips of the University of Santiago de Compostela in Spain, who with colleagues recently used a DNA sample to correctly infer the ancestry of a suspect in the 2004 train bombings in Madrid. After expressing skepticism about the goal,Phillips suggested some research the FSS could conduct but says he heard no more from them.
Mark Thomas, a geneticist of University College London who considers the Human Provenance program “horrifying,” contends that even determining a person’s ancestry--as distinct from nationality--is more problematic than many believe. “mtDNA will never have the resolution to specify a country of origin. Many DNA ancestry testing companies have sprung up over the last 10 years, often based on mtDNA, but what they are selling is little better than genetic astrology,” he says. “Dense genomic SNP data does have some resolution … but not at a very local scale, and with considerable errors.”
Details of the plan to use isotope analyses in addition to DNA analyses have intensified skepticism. The plan is to look for ratios of certain isotopes in tissue that could be matched to ratios in the environment where a person was born or grew up. But isotope specialists point to a seemingly obvious flaw: There’s no scientifically accepted evidence that isotope signatures at birth or during childhood are still present in adult samples of constantly growing tissues such as hair and nails. At best, researchers say, those tissues reflect the past year or so of a person’s life. “It worries me as a scientist that actual peoples’ lives are being influenced based on these methods,” says Jane Evans, head of Science-based Archaeology at the National Environment Research Council Isotope Geosciences Laboratory in Nottingham.
Although the agency hasn’t detailed the isotopes it is examining, the use of hair and nail samples suggest the tests will look at “lighter” element isotopes, such as those of hydrogen, oxygen, carbon, and nitrogen, all of which are incorporated into the keratin and other proteins as those tissues grow. Isotopes of strontium and other “heavier” elements incorporate into bones and teeth throughout life and some evidence suggests that strontium measurements can match people to geographic locales in which they were born, or at least grew up. In contrast, the lighter isotopes in tissues such as hair and nails being collected by the Border Agency are typically used to reveal recent diets and climatic conditions, not ethnicity. “I don’t think I could tell the difference between a Kenyan and a Somalian,” says Tamsin O'Connell of the University of Cambridge in the United Kingdom, an archaeologist who specializes in studying light isotopes from soft tissues.
O’Connell, Evans, and others say they’re puzzled that one Border Agency document titled “Nationality-Swapping” uses the notorious “Adam Torso” case as a proof of principle for employing isotope analysis. In this highly publicized murder in 2001, only the mutilated torso of a teenager was found in the Thames river. Using isotope analysis, “the child’s body was traced to a small Nigerian town in an area about 100 x 50 km wide,” a Border Agency document states (The documents and further scientific reaction will be found at this link). The document notes, however, that the analysis was done on bones, not hair and teeth. “It’s like adding 2 and 2 and getting 3 ½,” says Jessica Pearson of the University of Liverpool, who uses isotope signatures from fossils to examine the diet of ancient humans. Pearson also points out that the forensic methods used in the Adam Torso case are impossible to evaluate because they still haven’t been described in a scientific publication or discussed in court.
Having their fate rest on unproven methods is particularly dangerous for asylum-seekers in the United Kingdom, notes Phillips, because unlike criminal defendants, they have limited or no rights to challenge evidence or appeal. “You can’t parachute in a technique if it isn’t properly validated,” he says.
The Border Agency says only asylum-seekers who have already failed linguistic tests—another contested method of determining nationality—will be asked to provide mouth swabs, hair and nail samples. It also released a written response to scientific criticisms, which said: “Ancestral DNA testing will not be used alone but will combine with language analysis, investigative interviewing techniques and other recognized forensic disciplines. The results of the combination of these procedures may indicate a person's possible origin and enable the UKBA to make further enquiries leading to the return of those intending on abusing the U.K.'s asylum system. This project is working with a number of leading scientists in this field who have studied differences in the genetic backgrounds of various population groups.”
The Border Agency has not yet responded to a request to identify the scientists it is working with, nor has it cited any scientific papers that validate its DNA and isotope methods. It’s also not clear who is conducting the DNA and isotope analyses for the Border Agency. Evans says her lab, which is arguably the U.K.’s leading academic center for isotope studies, is not involved. Several researchers say they suspect private labs are doing most of the work—and they question if such labs have been properly vetted for reliability. Among their many concerns, some scientists also worry that statistical uncertainties may be overlooked.
A Border Agency spokesperson defended its Human Provenance program as a “small pilot at the moment. It’s in its baby stages. We want to get feedback.” They’re getting plenty of that from outraged scientists. “I'd hate to see asylum decisions made [with these methods]. It's peoples' lives we're dealing with,” says Pearson.