Genetic research has a white bias and is likely to affect the health of all.

Modern humans originated from the African continent more than 300,000 years ago, and subsequent generations migrated across the country, with groups marrying or separating. Some 80,000 years ago, a small number of descendants left the continent and spread around the world, taking with them a subset of genes and genetic variations developed by their ancestors.

However, genetic studies are now dominated by this subset, according to a new Cell article.

Last year, 78% of people included in the main form of genomic research – genome-wide badociation studies (GWAS) – were of European origin. But all over the world, Europeans and their descendants represent only 12% of the population.

According to the researchers, highly biased genetic databases could – and do – lead scientists and doctors to diagnose conditions or to prescribe treatments that may interest people with European genes, but not people of other racial origins .

"If we do not include ethnically diverse populations, we run the risk of exacerbating health inequalities," said Sarah Tishkoff, co-author of the study and human sciences geneticist at the University. of Pennsylvania.

How does this affect the equality of health care

Two humans in the world share about 99.9% of their DNA one with the other, but this 0.1% variation is extremely important. This variation may only concern single replacements here and there in the four-letter code of a person's genetic material and can mean the difference between a gene coding for healthy proteins and a faulty gene that makes a person sick.

Genetics interacts with other factors, such as diet, physical activity and access to resources, all of which determine a person's health. And health treatments that do not account for variations in genetically different populations can be problematic.

Some minor modifications in the genetic code can have significant effects on the effectiveness of a drug such as warfarin, which dilutes the blood, and therefore on the amount of effective and safe medication for the patient.

But these changes are only well studied among Europeans, say the researchers. The algorithms that help doctors prescribe the right amount of warfarin to a given patient work quite well for people with European genes, but are much less accurate for African Americans. In a study of 274 African American patients, one of these genotype-based algorithms routinely prescribed too many drugs, which resulted in a high risk of uncontrolled bleeding.

Without better data and adaptation to more genetic variations, prescriptions designed to help patients could ultimately harm them.

Why is it important

The lack of genetic diversity is "a social injustice and a missed scientific opportunity," said Esteban Burchard, a physician and epidemiologist at the University of California at San Francisco, who was not involved in the new document. "But that's not surprising."

In his own research, Burchard works on asthma, the most common disease in children, and finds similar disparities in studies of Americans in Puerto Rico. When proposing research on minorities, he added, committees and funding agencies are asking how this research will spread to the white population. "They never ask the opposite."

The researchers in the study also claim that biased genetic databases are lacking in research on human genetic variations.

Human populations acquire distinct genetic mutations over time, by selection or genetic drift. The more we will have to study more genes, the more likely we will discover those that are particularly useful for understanding the functioning of a disease or the eventual creation of a treatment.

For example, a genetic mutation found in people of African descent, has become a prime target to help scientists understand how cholesterol is regulated in the body.

"This is a great example where a rare mutation removes a gene," said University of Pennsylvania geneticist Giorgio Sirugo, who also contributed to the paper.

Once the researchers understood why this suppression of this gene helped lower cholesterol, they were able to create treatments that mimic this effect, giving rise to drugs that may be suitable for people of all races.

How to fix it

It is no coincidence that there is a disparity between the people represented in the genetic studies.

This is partly convenience, the researchers said. When studies are primarily conducted in the United States or Europe, researchers will likely use the racial majority where they live.

The human reference genome, for example, from the $ 2.7 billion human genome project, was constructed from samples taken in Buffalo, New York, a predominantly European region. Its limits are becoming clearer.

Similarly, even when studies come from institutions in the United States and Europe, they may have difficulty in finding accurate and reliable medical equipment and facilities for quality genetic research. In rural areas of developing countries, researchers may not have access to reliable electricity, let alone microscopes, refrigerators or more sophisticated laboratory equipment.

But it is also a historical trauma. Minority populations have faced serious medical abuse, as has the infamous Tuskegee study, in which hundreds of black men with syphilis were observed by doctors but died without treatment. For the black communities of America, trust in medical institutions is always tainted by these injustices.

In light of this story, "it must be done well. Ultimately, [the people who participate] should be those who will benefit from the information we get, "said Tishkoff.

Burchard added that in the world of research and politics, the climate is tense when it comes to talking about race.

Although race can not and does not divide humans into biologically distinct populations, it is a useful indicator of genetic and social patterns for public health researchers, Burchard said.

And yet, discussions about race, diversity and social justice are increasingly polarized, even within the scientific community.

"All of our work is about racial difference, but it's the first time in my career at UCSF that I'm afraid to lecture," Burchard said.

Although the National Institutes of Health is working to narrow disparities in genetic research, at least for minority populations in the United States, researchers say there is much more work to be done. Most of this work involves funding studies on the genetics of people who are scientifically underrepresented in the world.

"By not including diversity, we lack great opportunities to make new discoveries and to further include the world's people," Burchard said.