A report revealing China’s effort to collect DNA from millions of men to help solve crimes is raising concerns among researchers about privacy and consent. They say people have little control over how their information is used, and probably do not understand the implications that DNA collection has for their families.
Chinese state media first reported the government’s intention to construct a national forensic DNA database in 2017. But a report released on 17 June compiled by the Australian Strategic Policy Institute (ASPI), a think tank, reveals the scale, and key details, of the operation for the first time: for several years, police have been collecting DNA from men and school-aged boys across the country. They aim to collect and store genetic profiles of roughly 10% of the country’s male population — as many as 70 million people, according to the report.
The report estimates that those DNA profiles can be used to construct genetic links to China’s entire male population, roughly 700 million people.
The Chinese government says the database will help it to track down criminals, who are mostly male. But the report also describes the operation as part of government efforts to “deepen” social control.
Scientists and human-rights activists say a genetic database containing information about people without a criminal history is unprecedented.
“This is really unique. No other country is doing it,” says Mechthild Prinz, a forensic geneticist at John Jay College of Criminal Justice in New York. “They just go and get people that are regular citizens. It is very heavy-handed,” she says.
Researchers also fear that police might use the database to persecute people who criticize the government. “This collection has nothing to do with crime — it has to do with oppression,” says Maya Wang, a researcher at the non-profit group Human Rights Watch in Hong Kong.
The ASPI report says that the database, which is run by China’s Ministry of Public Security, expands on previous DNA-collection efforts. Like other countries, China has a large database of DNA from suspected and convicted criminals. But it has also collected DNA from minority ethnic groups in Tibet and in the northwest province of Xinjiang, which has been criticized by human rights groups.
The type of genetic information that China is collecting is also controversial, because it can be used to track down family members who have not given DNA samples. The database catalogues markers known as short tandem repeats (STRs), repeating regions of DNA that are specific to the male-defining Y chromosome. Y-specific STRs are extremely similar between men in the same male lineage. This means that a Y-STR sample from an unknown male can be linked to all his male relatives on his paternal side. And when Y-STR data is combined with other data such as family trees, it is possible to identify an individual.
In 2019, Chinese police used the database to identify a man who had committed murder in Guangzhou in 2008. Police used DNA from the crime scene and found a match in the database to one of the man’s relatives, who had previously been arrested for burglary. That was enough to establish a link with the murderer, who lived in Malaysia. Chinese police apprehended him the next time he entered the country.
Law-enforcement agencies in other countries have used this technique in criminal investigations. But researchers say that data is typically collected for a specific investigation and destroyed immediately afterwards, whereas China plans to store Y-STR profiles indefinitely. Prinz says that such data collection is tightly regulated in most countries, but China’s database is not subject to any law.
To reveal the size of the Chinese government operation, the authors of the ASPI report compiled more than 700 Chinese-language documents that include information about genome sequencers purchased by local police, social-media accounts of local security bureaus and local media reports. The documents also detailed local campaigns to collect citizens’ DNA in 22 out of China’s 31 administrative regions excluding Hong Kong and Macau. In documents, local police boasted that they would collect samples — by compulsion if necessary — from 8% to 26% of the local male population.
Scientists are particularly concerned about reports that blood samples are being collected without proper consent, and without informing people how those samples will be used. They say the database could also be used for purposes other than investigating crimes, such as finding couples who had had multiple children under China’s previous one-child policy, or tracking down and punishing family members of people suspected of political crimes or criticizing the government.
“You can think of nasty uses if you are creative,” says Itsik Pe’er, a computational biologist at Columbia University in New York City.
And because Y-STR data can be used to construct family links, researchers say it could also reveal private information, such as paternity, in people whose information is not in the database. In China, there are no privacy protections, says Wang. “Police basically do whatever they want,” she says.
In China, there has been some criticism of state-wide DNA collection. In 2015, a scientist at the Ministry of Public Security wrote in the journal Forensic Science and Technology1 that there is no legal basis in China for making a database of Y-STR data. And delegates at the governments’ national assembly in March called for DNA collection to be regulated, although it is unclear whether that will happen.
The Ministry of Public Security did not respond to Nature’s request for comment on the risks that the database could be used for purposes other than criminal investigations. On 22 June, an article in Chinese state news agency Xinhua said ASPI was supported by US technology companies and was intent on slandering China, although it did not comment on the Y-STR report.
James Leibold, a senior fellow at ASPI and co-author of the report, disputes the Chinese government’s characterization of ASPI’s work. He says the institute does get some funding from companies in the US and elsewhere, which is disclosed on its website, and its research undergoes peer review. “There is no single editorial line on China, just fact-based empirical research to inform public opinion,” says Leibold, who is also an academic in politics and media at La Trobe University in Melbourne.
Some researchers have wondered why Chinese officials are cataloguing only Y-STR data, when, with a little extra effort and resources, they could catalogue sequence data from the other 22 pairs of chromosomes in the body. These are unique to an individual and so could be used to identify a person. “This little effort would produce a much better forensic tool to fight crime,” says Fulvio Cruciani, a forensic geneticist at the Sapienza University of Rome.
Cost and ease of use are two reasons that China might stick with a Y-STR database, says Prinz. Y-STRs are cheap, and data can be analysed at any of the hundreds of crime laboratories across the country.
Other scientists, such as Fabricio Santos, an evolutionary biologist at the Federal University of Minas Gerais in Belo Horizonte, Brazil, thinks Chinese officials are probably storing blood samples to ensure that they can perform more-detailed analysis in the future, if they choose to. “It is a matter of cost and time, but the DNA samples will always be there,” says Santos.