Oppressed and used as scientific guinea pigs. The Uighurs, the Muslim minority under strict Chinese surveillance in the Xinjiang region, are forced to give their blood to the Chinese authorities. They use it to build a large biometric file and to research an emerging technology, which is generating many fantasies: DNA phenotyping, says the New York Times Tuesday, December 3. This technique aims to deduce physical characteristics of DNA.

The survey of the American daily has caused a stir in the scientific community. The New York Times says, indeed, that this research must allow China to make facial imaging reconstruction from DNA. Clearly, Beijing would seek to perfect this technology to be able to establish robot portraits from blood samples, to improve its facial recognition algorithms. The Chinese Big Brother would feed, like a technological vampire, the blood of its population to better monitor it. Except that in the opinion of all the experts interviewed, the ability to create DNA-based robots portraits is still science fiction rather than reality.

Technological vampire

One of the reasons this fantasy about DNA profiling took hold is a 2015 news story in South Carolina. In a double murder case, the police had circulated a computer-generated suspect portrait of a suspect from a DNA sample taken at the scene of the crime. But nothing indicates that this technological feat played a decisive role in the arrest of the alleged killer. "You have to be aware of the limitations of this technology so as not to exaggerate the possibilities offered," says Matthias Wienroth, a researcher at Newcastle University, who works on the ethical and social implications of the use of biotechnology and co-authored a letter. open on the use of DNA phenotyping in criminal cases, contacted by France 24.

DNA phenotyping is a relatively new technology "whose origins date back to the end of the 1990s, but which has been of real interest only since the year 2010 when concrete applications seemed possible," explains Matthias Wienroth. The idea is to identify in a person's DNA the genetic markers that affect physical characteristics. "At the moment, we can predict from the DNA what is the color of the eyes, that of the hair or even the skin. But this is a general category, "explains Manfred Kayser, director of the genetic identification department at Erasmus MC University Medical Center Rotterdam, contacted by France 24. The technology does not allow, for example, to differentiate between light blue or dark blue eyes or between light blond and chestnut hair. It can also provide information on geographical origin, indicating whether a person comes from Europe, Africa or Asia.

Guess the color of hair, eyes or skin

As with any recent technology, knowledge also evolves very quickly. "We expect to be able to predict in the future the structure of the hair, the presence of moles, the color of eyebrows or if a man is bald or not," says Manfred Kayser, one of the world's leading specialists DNA phenotyping.

Promises that are of primary interest to forensic science and the police. While in Europe, the use of this technology is still largely banned, in the United States, "it has already been used in several cases," says Matthias Wienroth. But be careful not to shout "eureka" at the slightest trace of DNA found at the scene of a crime. The analysis of the genetic code "only gives probabilities and not certainties," says the specialist from Newcastle University. It does not allow, either, to identify "individuals, but only types of people," notes this expert.

This is why the idea of ​​robot portraits still seems absurd to them. "If you were trying to make a computer guess what I looked like from my DNA, it would bring out a typical European face," says Peter Claes, a researcher at the Catholic University of Leuven, who has been working for more than a year. a decade on this technology. First, because scientists are still far from understanding all genetic markers, which affect the shape of a face. And secondly, because "we also have to take into account environmental factors, such as a particular diet, that can affect our appearance and have nothing to do with genetics," says Peter Claes.

Prejudice and stereotypes

For him, DNA phenotyping must first and foremost be used to "eliminate potential suspects who do not belong to the types of individuals designated by the analysis of the genetic code". That's what happened in 2003 during the hunt for a serial killer in Louisiana. The police had identified a suspect who matched the psychological profile, but traces of DNA bleached him because he did not have the right skin color.

Proceeding by elimination also minimizes one of the main risks highlighted by the experts interviewed: that DNA phenotyping accentuates prejudices and stereotypes. If the DNA analysis indicates that a suspect is not Caucasian, "it should not force the police of a European country to search only among the immigrant population" because there may very well be national citizens of color, notes Matthias Wienroth.

DNA phenotyping is therefore a new tool "which should not be exaggerated or deny defects," stresses Matthias Wienroth. China is probably not in the process of building a huge Uygur portrait-robot file thanks to their DNA. What is much more likely "is that the authorities are trying to identify the characteristics that make it easy to identify who belongs to this minority," Peter Claes said. A worrisome genetic profiling work that he says is "likely to give a very bad reputation to a technology that, moreover, can be very useful if it is used wisely."