Genetics without borders

Until a few years ago, the genetic variation of humans was understood only in terms of superficial characteristics, such as hair and skin colour. Today, thanks to the advent of cheap, fast genetic sequencing and DNA-microarray technologies, population geneticists can chart such variations in a more systematic way. Yet most experts agree that these studies are still in their infancy.

So it was with understandable unreliability that researchers received a scheme by the UK Border Agency to use genetics to determine nationality – specifically, asylum seekers claiming to be of origin from war-torn Somalia.

The agency’s pilot program, which began last month, aims to determine whether some 100 individuals are in fact Somali citizens, by checking them for individual DNA variants known as single nucleotide polymorphisms (SNPs) in mitochondrial DNA. on the Y chromosome and elsewhere in the genome. The plan will also use isotopic ratios of elements found in hair and nails – which can vary depending on a person’s diet or environment – ​​to attempt to establish where migrants first lived.

The Border Agency says the project has undergone scientific peer review, although it is difficult to say by whom: several geneticists contacted by Nature saw the initial proposal from the UK government in 2007, and warned it was unlikely to work. Was.

It is true that the recent development of large SNP databases has made it possible to determine the geographic origin of Europeans to within a few hundred kilometers (see Nature 456, 98–101; 2008). But comparable data on many human populations, especially in areas such as Africa, is best, and it is unclear what data the border agency will use to establish the origins of these particular asylum seekers.

On a more fundamental level, the idea that genetic variability follows man-made national boundaries is absurd. Cross-border migration is common around the world; Y-chromosome analysis can be easily carried away by a distant male ancestor; And SNP-based identifications are not accurate, to say the least. As an example of this last point, individuals whose parents come from two geographic regions are often classified in a third region, from which the parents did not originate.

The use of isotopic analysis to identify nationality is also unproven. Although it may be possible to use isotopic ratios to determine the area in which a person has recently lived, this cannot provide definitive evidence of their origin.

These problems are overlooked in guidelines provided to border agents testing asylum seekers. Given the scientific credibility of DNA evidence, it is not hard to imagine that these agents – who are likely not geneticists – could place undue weighting on results that are at best, difficult to interpret and, at worst, fake.

Migration organizations and geneticists alike have been vocal in their opposition to the plan, and the UK government has backed down in response. In a statement released earlier this week from the Home Office, which runs the border agency, the program was described as simply a proof-of-concept project that could be used to make decisions about any asylum-seeker. will not be done.

But the government should outright cancel this scientifically dubious and politically sensitive program. If allowed to continue, it could easily lead to a public backlash in the very population that geneticists need to study to understand the human origins and genetic basis of disease. Geneticists, and indeed all scientists, should condemn the plan and make it clear that science does not support it.

Leave a Comment