Researchers call for inclusion of African populations in genetic studies for health
Genetic studies must be more representative of Africa and its people, according to researchers. This will improve the study of diseases on the continent and worldwide, and help to develop better medicines for all.
Humans originated in Africa and the continent is still home to diverse groups of people. Despite this, populations from across Africa are seldom included in genetic studies.
By 2018, 81% of all so-called genome-wide association studies (GWAS) only included participants of European descent. Of the rest, only 3% included people with African ancestors. Most of these included African American or West African participants, and very seldom people living south of the Sahara. This includes people from Afro-Asiatic, Nilo-Saharan, Khoisan, and Niger-Congo language families.
With GWAS studies researchers are able to detect genetic, and therefore inherited, associations or links between large groups of people.
Because of a lack of representation of African populations in such studies, there are major gaps in what scientists actually know about health matters of a genetic nature.
This can lead to doctors making incorrect predictions about whether someone might get a disease or not based on genetic test results. They could also incorrectly prescribe medicines and dosages to people belonging to certain unstudied groupings.
For example, in South Africa researchers struggled for years to understand why tuberculosis spread more in some population groups than in others. The picture only became clearer after genetic and ancestry studies were done.
Researchers from the USA, South Africa and Ethiopia provided reasons why so many GWAS studies tend to be Eurocentric, and what can be done to ensure greater African diversity in studies, genetic resources and research efforts.
They summarised the findings of many previous GWAS studies completed, and why from a medical and health perspective such studies must include information from all populations across the world.
Their summary included notes on the history of GWAS, and the infrastructural and funding challenges standing in the way of more studies being done using the genetics of people of African descent.
They also noted how important it is that studies are done ethically, with the necessary respect, and with consent from participants.
It showed that a lot of work is still needed to ensure that people from all African population groups are adequately included in GWAS studies.
Such projects must include researchers from Africa to ensure further representation and to develop skills.
According to the research team, it is possible to fill existing gaps in knowledge about human genetics in all of its diversity. Such work will provide more insights into specific traits and diseases of a genetic origin, and how to develop suitable new drugs.
It will benefit people from population groups that are currently not represented in GWAS studies.
Statistics clearly show how in the past African populations were not included in GWAS studies, and how information gaps can be filled.
But the researchers involved say that progress has so far been slow.
They believe that the skills of scientists in Africa can improve if they are given the chance to work together with research groups from elsewhere.
Funding for research projects and the development of researchers must be thoughtfully planned to benefit those countries with the greatest public health needs.
Human genetic studies have long been vastly Eurocentric, raising a key question about the generalizability of these study findings to other populations. Because humans originated in Africa, these populations retain more genetic diversity, and yet individuals of African descent have been tremendously underrepresented in genetic studies. The diversity in Africa affords ample opportunities to improve fine-mapping resolution for associated loci, discover novel genetic associations with phenotypes, build more generalizable genetic risk prediction models, and better understand the genetic architecture of complex traits and diseases subject to varying environmental pressures. Thus, it is both ethically and scientifically imperative that geneticists globally surmount challenges that have limited progress in African genetic studies to date while meaningfully including African investigators, as greater inclusivity and enhanced research capacity affords enormous opportunities to accelerate genomic discoveries that translate more effectively to all populations. We review the advantages and challenges of studying the genetic architecture of complex traits and diseases in Africa. For example, with greater genetic diversity comes greater ancestral heterogeneity; this higher level of understudied diversity can yield novel genetic findings, but some methods that assume homogeneous population structure and work well in European populations may work less well in the presence of greater diversity and heterogeneity in African populations. Consequently, we advocate for methodological development that will accelerate studies important for all populations, especially those currently underrepresented in genetics.
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