The once widely held notion that humans fall into discrete races has led to geneticists drawing erroneous conclusions about the role of genes in shaping health and traits, and in some cases, to harmful discrimination against some groups. An expert committee is now urging an overhaul of this practice. Most notably, the committee’s report calls for researchers to scrap the term “race” itself in most studies, use caution with other labels such as ethnicity and geography, and determine ancestry by quantifying how closely a group’s members are related to reference genomes drawn from certain populations.
“We’re calling for researchers to be more specific about what they’re trying to do,” says Duke University geneticist Charmaine Royal, co-chair of the committee, which was convened by the National Academies of Sciences, Engineering, and Medicine (NASEM) and released its report today. The imprecise use of certain descriptors has “been a big problem in the genomics community, and it’s going to be a big change” to adopt a more thoughtful approach, she adds.
NASEM formed the panel at the request of the National Institutes of Health. The panel’s report finds that “race,” or the notion that populations fall into a few distinct, stable biological groups, is a social classification and not a scientifically valid way to measure genetic variation. All populations have mixed and moved over time; Europeans today have Middle Eastern ancestry, for example, and most Black Americans, who usually have African ancestry, also have varying amounts of European ancestry. Geographic location, such as East Asian, can overlook genetic variation within that region. And ethnic labels such as Latino often reflect culture, not genetic ancestry, the report says.
The committee suggests researchers should instead determine a group’s ancestry using “genetic similarity,” or by calculating how closely its members are related to collections of genomes from distinct populations that are known as reference genomes. One widely used reference called 1000 Genomes is drawn from sampling the DNA of groups in various locations, such as Gujarati immigrants in Houston, the Yoruba of Nigeria, and Tuscans in Italy. Scientists could quantify how close a group or individual’s genome is to one or more of these reference groups, the report says.
The committee sites recent arguments by some researchers that using reference genomes would be more precise than applying broader labels such as northwestern European. Committee co-chair Aravinda Chakravarti, a geneticist at New York University, compares the approach to GPS that pinpoints a person’s location using data from scattered satellites. “As we get more reference samples from more parts of the world, that’s what we’re going to do,” he says.
Researchers should then “tailor” their use of other population descriptors to their study, the report says. For example, no labels at all may be needed for cells used to study a disease if the mechanisms are thought to be the same in people of all backgrounds. For researchers searching for new disease-causing genes, a person’s ethnicity may be relevant if it means environmental factors such as poverty, discrimination, or chemical exposures influence the person’s health. And scientists studying human evolution may need to include the geographic location where samples were collected to help trace a group’s history, for instance.
The one research area in which a person’s perceived or self-identified race may be relevant, the report says, is for studies of health disparities, where racial categories can often serve as a proxy for how structural racism—societywide policies that result in disadvantages to certain groups of people, often on the basis of race—affects an individual’s health or leads to inequities in the medical care they receive.
Many human geneticists have already dropped the term “race” from their studies. But other recommendations in the report will be new to researchers using genomic data and challenging to put into practice, says clinical and molecular geneticist Wendy Chung of Columbia University, a report reviewer. “I think the report is extremely important and comprehensive,” she says. “The issues are nuanced and sensitive, so I think it’s helpful for researchers who don’t think about this deeply to have guidance and deeper understanding.”
Source: Science Mag