Can DNA Tests Reveal Nationality?

When it offers political asylum to Somali refugees, the British government wants to make sure it isn’t inadvertently opening its doors to non-refugee immigrants from other African nations. This recently inspired a screening process that scientists say is deeply flawed: genetic nationality testing.

In mid-September, the United Kingdom Borders Agency started the Human Provenance program, performing DNA tests and chemical tests called isotope analyses in hopes of establishing the nationality of asylum seekers whose origins were uncertain. While the tests were voluntary, the information they generated was to be used in making official decisions about whether a person would be granted asylum.

Britain’s scientific community, not to mention immigrants’ rights groups there, were outraged, saying that the tests were scientifically worthless — nationality isn’t encoded in DNA. The program was suspended on October 5. On November 20, the Borders Agency reinstated the effort as a scaled-back pilot program, to “test whether there is the potential for these investigations to be supported by wider use of DNA testing and isotope analysis,” Chief Scientific Advisor Paul Wiles wrote in a prepared statement in October. He added that for the duration of the pilot program, “no decisions on individual cases will be made using these techniques, and they will not be used for evidential purposes.”

So, what, exactly, can DNA tests and isotope analyses reveal about nationality?

The Borders Agency is primarily using two types of DNA tests: mitochondrial DNA tests, which examine the genetic information stored in a cellular structure called a mitochondrion, and what are called Y-line tests, which look at markers on the Y-chromosome passed from father to son.

These tests have been widely used to examine people’s ancestral heritage. Since certain genetic variations are typical in certain areas, geneticists can use an individual’s DNA to estimate where their ancestors came from.

But when this technique is used to look at someone’s nationality rather than the origin of their distant ancestors, critics say it’s no longer viable.

“I don’t see how genetics can tell us about nationality, because nationality is a social and political construct, not a genetic one,” said Chris Tyler-Smith, head of the human evolution research team at The Wellcome Trust Sanger Institute, a genomic research center in the U.K. “I wouldn’t be able to [distinguish a Somali from a Kenyan] using the mitochondrial DNA and the Y.”

In addition to DNA tests, the Human Provenance program attempts to glean geographical information by analyzing chemical markers called isotopes found in hair and fingernails. Different environments have different isotope levels, and as a person drinks water or eats food from a given place, the isotopes it contains are absorbed into the body.

There is some evidence that isotope analysis of hair can give a general idea of where a person came from. But, said Jane Evans, a researcher at Britain’s Natural Environment Research Council Isotope Geosciences Laboratory, “if you want to know where somebody spent their childhood, you’ve got to look at a part of the body that records information about childhood. Hair and fingernails are only going to tell you something, maybe, about what the person did while those were growing.”

Hair grows about half an inch each month, so even a six-inch hair will provide clues only to the past year’s geography. Fingernails tell even less. Since many asylum seekers don’t immigrate directly to the U.K., these tests are unlikely to be useful.

Here in the United States, the government has no plans to institute a similar program. U.S. officials “have not used, nor are they considering DNA testing for verifying nationality,” said Chris Rhatigan, a spokeswoman for U.S. Citizenship and Immigration Services, in an e-mail.

It will take time to gather and analyze data from the U.K. pilot program. But, Tyler-Smith said, “I haven’t seen any scientist who has supported the idea of these tests or [thought] that they’re appropriate or meaningful.”