Scientists have released a new-and-improved edition of the human genome that better captures the diversity of human genetics. Called a “pangenome,” this map of genetic code represents people of various ethnic backgrounds and can serve as a reference for scientists looking to predict, diagnose and treat disease.
The findings, documented in a group of papers published Wednesday in Nature, could make genetic research more helpful for a more diverse range of people.
“It’s been long needed—and they’ve done a very good job,” Ewan Birney, a geneticist at the European Molecular Biology Laboratory who did not contribute to the work, tells the New York Times’ Elie Dolgin.
“It’s an exceptional advance,” Mashaal Sohail, an evolutionary geneticist at the National Autonomous University of Mexico who was not involved in the research, tells Science’s Rodrigo Pérez Ortega. “It’s making the picture of human genetic variation more accurate and more complete.”
Having a reference genome is crucial to medicine. Doctors use this genetic blueprint to identify mutations in their patients and diagnose genetic conditions; scientists use it as a point of comparison for DNA sequences in their research. The first human reference genome draft was released more than 20 years ago. By 2003, scientists had constructed a reference genome that covered about 92 percent of the total human genome sequence and was 99.99 percent accurate, according to the National Institutes of Health.
But this early draft of the human genome was informed by a limited range of sources. Around 70 percent of its DNA came from one mixed race man in Buffalo, New York, according to the Washington Post’s Mark Johnson. The rest largely came from people of European descent. Essentially, the guide to what “normal” human DNA looks like was based mostly on one man and European heritage.
The new pangenome contains sequences from 47 different individuals. It includes people from Africa, the Americas, Asia, Europe and the Caribbean Islands, according to Nature News’ Layal Liverpool. It also adds 119 million base pairs—which form the “rungs” of the DNA ladder—that were not present in earlier reference genomes, helping to close the gaps in prior data.
“It’s something that we have all been waiting for,” Aimé Lumaka, a geneticist at the University of Kinshasa in the Democratic Republic of the Congo and the University of Liège in Belgium who did not contribute to the findings, tells Nature News. “The current reference genome is missing not only part of the genomic information, but, most importantly, it’s missing diversity.”
Using a reference genome that’s mostly from people with European ancestry could reinforce disparities in medicine. When that reference is used to predict the risk of certain diseases, the results may not be accurate for those who are not of European descent, writes Science.
Without a diverse genome, researchers might also miss genetic variants that only occur in certain groups of people, Timothy O’Connor, a human geneticist at the University of Maryland who did not contribute to the research, tells Science News’ Tina Hesman Saey.
“We’re missing quite a bit of information that can contribute to our knowledge of health disparities and health inequities,” Krystal Tsosie, a genetic epidemiologist at Arizona State University, tells Science.
Though the pangenome is a big step forward, the researchers still have work to do to make it reflect global human diversity. “It’s still underrepresenting Latin Americans and Indigenous Americans, and … there’s nobody included from Oceania,” O’Connor tells Science News. “There’s still a lot more variation that needs to be added to the pangenome to really, truly be representative of everyone.”
The researchers hope to expand their reference genome to include sequences from 350 different people by the middle of next year.
They’re also tackling ethical questions surrounding the collection of DNA. In the past, researchers with the Human Genome Project were criticized for not engaging well enough with the marginalized communities they were sampling and for not recognizing their needs.
“I am concerned that many of the participating pangenome locations have samples that were collected in the 1980s under very different political and social structures,” Latifa Jackson, a geneticist at Howard University, tells Nature News. “We need to revisit ideas of consent, especially for samples collected 30–40 years ago under very different power structures.”
The researchers are now working with Indigenous groups to come up with policies for data ownership, writes the New York Times.
Tsosie, who is Diné, tells Science that researchers need to not only use diverse genomes, but also collaborate with the groups involved in the research to understand their health needs. “If the research is not benefiting the diverse communities first and foremost, then we are doing something fundamentally wrong here,” she tells Nature News.