[ad_1]
IIn the post-genomic era, our genes dictate our health. Now, a 23 & Me DNA test kit at home can warn you of your risk of hair loss, or prenatal screening will reveal your baby's risk of hereditary disease. We take for granted that there are genes related to each trait or disease, but we do not often think about how these badociations are created. As the authors of a disturbing comment in Cell press recently revealed, there is a huge problem in the way scientists do it.
It is shameful.
Geneticists make these badociations by tapping into DNA from samples of people believed to represent a larger human population. Unfortunately, as discovered by Sarah Tishkoff, Ph.D., co-author of the commentary and geneticist of human evolution at the University of Pennsylvania, about 78 percent this data comes from people of European descent.
"It's shameful," she says reverse, en route to Oregon and San Diego to engage scientists to increase research diversity. "We have to do something about it."
A white bias means that the conclusions that scientists can draw from the data may be applicable only to people of European descent. These incomplete surveys of health and disease risks could have disastrous consequences for people of all ethnicities, including Europeans.
"It does not just benefit the different ethnic groups you could study," says Tishkoff.
An omnipresent problem of diversity
All we know about genes related to disease risk comes from genome-wide badociation studies, or GWAS. In these studies, researchers sequenced the genomes of thousands of participants and then searched for badociations between idiosyncrasies of the human genome standard sequence (known as single nucleotide polymorphisms, or SNPs) and certain traits.
We thought it might be better.
Since 2008, all published GWAS have been cataloged in a database managed jointly by American and European institutions. Tishkoff and his co-authors examined the ethnic distribution of all studies published in this country, hoping to see a change in the European bias documented in previous badyzes.
"We thought it might be better. Some people looked at it a few years ago, "she says. "But that was not really the case. Just a little, but not a lot. "
In 2009, 96% of the people represented in GWAS were of European origin. In 2016, this proportion was 81%. Now it's 78% – a slight improvement, but not enough. The human population does not include 78% of people of European descent, yet the conclusions drawn from the GWAS data are supposed to benefit everyone. The other people represented in the GWAS studies are composed of 10% of Asia, 2% of Africans, 1% of Hispanics and <1% of all other ethnic groups.
Why is it important
The problem with this lack of diversity is that people of non-European descent may have different the genes badociated with the even studied diseases in Europeans. A cancer screening method designed with these data, for example, may not detect a cancer-related SNP only in Asians.
At present, we do not know what ethnic badociations we are missing. "Until people start to increase the number of diverse ethnic individuals in these studies, we will not know it," Tishkoff says.
… We could give people wrong information.
She learned the usefulness of doing this by discovering a gene related to the color of human skin in a landmark 2018 study focusing solely on 1600 Africans. "Now they discover that the gene plays a role in the risk of melanoma," she says. Such a gene could be used to identify risk in people of all ethnicities. "That's why it's very instructive to look at different ethnic groups," she says.
Tishkoff also points out that a white bias in the data used to diagnose people of other ethnicities will aggravate existing health disparities based on race. Already, health trends are sharply divided by race: black and Hispanic populations suffer from air pollution produced by white communities, and the HIV mortality rate of black patients is much higher than from their white counterparts.
"My biggest concern – I am really worrying is that we just do not know how much it will translate across ethnic groups, "says Tishkoff. "And if they do not translate well – and preliminary studies suggest they will not do it – then we could give people misinformation."
How's it going
The basis of these disparities lies in the GWAS itself and the people involved in their realization. According to Tishkoff, the population sample of a GWAS could be heavily influenced by a number of reasons. Some are more understandable than others, but none are excusable.
The first is who does the research and where. "A lot of this research is done in the US and Europe, and you're going to study the most common populations," says Tishkoff.
If you do, you may not be able to get your grant.
Then come people from non-European populations themselves, who may not want to participate in GWAS for a variety of reasons, the main one being mistrust. "Right, based on past injustices and bad practices," says Tishkoff. The American syphilis tests on Guatemalan prisoners and the brutal exploitation of the black patient Henrietta Lacks are just one example some examples that come to my mind.
The most complex is the question of funding. According to Tishkoff, the National Institutes of Health have historically sanctioned proposals for studies on genetically heterogeneous populations, that is, people who do not all have the same ancestry. The accepted reasoning is that studies on people of different ancestry tend to give false positive results, which Tiskhoff says "has been known for a long time". The fact that these studies appear to be worse in the eyes of the funder is usually due to smaller minority groups, and therefore they have less statistical power.
"If you do that, you may not get the money from your grant," she says.
How to fix it
Fortunately, the scientific community has been receptive to the call for greater diversity. "People are grateful," says Tishkoff. NIH now has an Africa-focused initiative to support genomic research on African people in African institutions, and some of its branches and projects require the inclusion of minorities and women.
Tishkoff's call for diversity was recently echoed by Joyce Tung, vice president of research at 23 & Me, who wrote: STAT"Social, cultural, economic and political barriers separate researchers and research funding from those who need it the most." these data to scientists.
This problem of diversity far exceeds the data and will require the work of scientists, policy makers and lay people to correct it. Inclusion starts with helping people of diverse backgrounds, especially in environments where they are underrepresented.
Tishkoff reports to the lab: "There must be more people of different ethnicities in the field of human genetics," she says. "I think people trust people who are more like them."
[ad_2]
Source link
