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  • Writer's pictureThe San Juan Daily Star

Guidelines warn against racial categories in genetic research

By Carl Zimmer

Grappling with the deep history of racism in Western science, the National Academies of Science earlier this week released guidelines recommending that scientists not use race as a category in genetic studies.

The guidelines, produced in response to a directive from the National Institutes of Health, noted that racial categories were poor proxies for genetic diversity and that social and environmental factors, like poverty and injustice, were often overlooked.

“The recommendations in this report provide a pathway to generate lasting change in an evolving field,” the authors said in a statement. The National Academies of Sciences, Engineering and Medicine, which was chartered in 1863 as an independent adviser to the nation on science and medicine, will host a public meeting Friday to review the report.

The 239-page document came out of months of work by a team of geneticists, social scientists and historians.

“I can tell you honestly I have never worked harder on any committee I have ever been on in my entire career, and I think every single person on that committee would say the same thing,” said Sarah Tishkoff, a geneticist at the University of Pennsylvania and one of the authors. “I think part of the reason for that is we felt a lot of weight on our shoulders.”

In the 18th century, European naturalists began claiming that humans belonged to clearly separate biological groups living on different continents. Visible traits like the color of their skin supposedly reflected deeper differences between the races in intelligence and morality. A hierarchy of scientific racism emerged, with white people at the top.

When the science of genetics emerged in the early 1900s, some early geneticists tried to validate the old notions of race by looking for genetic markers in groups of people. But now a century later, after sequencing millions of human genomes, scientists say it is abundantly clear that those notions do not hold up.

Tishkoff pointed to the genetic variation among people in Africa, where she has done field work for decades. Humans arose in Africa about 200,000 years ago and diversified into many populations, which have mixed together over thousands of generations. A wave of people expanded out of Africa about 60,000 years ago, spreading to other continents.

That history makes it impossible to identify a genetic makeup of all Africans that would correspond to a Black race. “There’s going to be more diversity between neighboring groups in certain regions of Africa than we see across the globe,” Tishkoff said.

At the same time, environmental variables can have potent biological effects on people. Groups who live in neighborhoods with high air pollution, for example, will have higher rates of certain diseases. The authors of the new study recommend building these environmental influences into studies, rather than looking at genes in isolation.

The authors created a flowchart to help scientists design their research. Different kinds of research call for different kinds of experiments.

Scientists looking for individual mutations that cause severe diseases, for example, may not need to consider the ancestry of their subjects at all. The mutation may well cause the same disease regardless of the ancestry of the person carrying it.

Other scientists look at the DNA of many people to reconstruct the ancestry of human populations. Tishkoff and her colleagues recommend that scientists don’t throw their subjects together in groups that don’t reflect their deep history. A national label like “Tanzanian,” for example, describes only people who live in a country that gained independence in 1961.

Instead, the authors recommend that scientists identify their subjects with meaningful information, such as their local ethnic group or language. In some studies, they said, it may be appropriate to describe subjects by the percentage of ancestry they can trace to different populations. When they publish their findings, researchers should be transparent about the grouping decisions they made so that other researchers can revise the groupings based on new evidence, the guidelines said.

Joseph Graves, an evolutionary geneticist at North Carolina A&T University who was not involved in writing the report, said it offered scientists a path out of some of the fallacies that have hampered previous studies on human health and variation.

“The strengths are really to help researchers disentangle the social definitions from the biological definitions,” he said.

But he warned that simply putting out a report would not be enough. “We need to get out there and be talking to our colleagues,” he said. “The report can work, but it requires people to get behind it.”

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