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Why and how Africans need to participate in genetic studies

- Wits University

Underrepresented populations need to feature more in genomic studies so that they benefit from research that explores how their unique genetics affect health.

A genome is the complete set of genetic information in an organism. It provides all of the information the organism requires to function. In living organisms, the genome is stored in long molecules of DNA called chromosomes. There are 23 pairs of chromosomes in the human genome.

Scientists at the Sydney Brenner Institute for Molecular Bioscience (SBIMB) at Wits University were part of the team that published A roadmap to increase diversity in genomic studies in Nature Medicine on 10 February 2022.

Collaborators include the African Computational Genomics Research Group in Uganda, London School of Hygiene and Tropical Medicine, University College London, and the Broad Institute of Harvard and MIT.

‘White-washing’ genomic research

Genetic and genomic studies are predominantly based on populations of European ancestry. The study found that, as at June 2021, 86% of genomics studies had been conducted in individuals of European descent.

For low- and middle-income countries (LMICs), lack of resources such as funds, institutional capacity and a skilled workforce are major barriers to genomic research.

At the same time, the proportion of studies conducted in underrepresented populations has either stagnated or decreased. Underrepresented populations include residents LMICs and indigenous and minority groups across the globe.

This means that the potential benefits of genomic research – including better understanding of disease etiology [origin], early detection and diagnosis, rational drug design, and improved clinical care – may elude the many underrepresented populations, including Africans.

Factors that have contributed to underrepresentation of different populations in genomic studies include:

  • Domination of European and American scientists in advances in genomic technologies and infrastructure and better funding opportunities
  • Lack of diversity amongst researchers, which drives bias in genetic studies
  • Political instability in some countries make investments in genomic studies erratic
  • Lack of trust of researchers because of historical research abuse and exploitation
  • Limited understanding of genetic concepts among some indigenous populations and limited data on effective models for community engagement.

Why it matters

Genome-wide association studies (GWAS) is an approach used in genetics research to associate specific genetic variations with particular disease. African populations have the most genetic diversity, followed by South Asians. These populations also have the most loss-of-function genetic variants, which can help scientists better understand how genetic mutations impact health.

“A lack of diversity in genomics leads to unmet scientific needs and health disparities. There are already clear examples of clinically important variants only discovered in underrepresented populations, for example, genetic associations implicated in kidney disease,” says Dr Ananyo Choudhury, co-author, senior scientist and Reader at the SBIMB.

Pockets of representative research excellence

“Despite the unequal representation of ancestry groups in genomic research, some studies in underrepresented populations have been very successful,” says Dr Tinashe Chikowore, co-author, Wellcome Trust training fellow and researcher at the SBIMB and the SA Medical Research Council Developmental Pathways to Health Research Unit (DPHRU) at Wits.

“One such success story is that of the H3Africa [Human Heredity and Health in Africa] consortium, which was the first major pan-African study to have a comprehensive spread across the continent and across a wide variety of diseases and traits.”

In a demonstration of how building on existing resources and forming long-term partnerships can enhance representation in genetic studies, the Africa Wits-INDEPTH Partnership for Genomic Research (AWI-Gen) includes 12 000 adults and spans Ghana, Burkina Faso, Kenya and South Africa. 

AWI-Gen was established by a strategic regional partnership between Wits University and the International Network for Demographic Evaluation of Populations and Their Health (INDEPTH) study.

The Medical Research Council/Wits-Agincourt Unit (Agincourt) is one of the research partners on AWI-Gen and the Agincourt platform is one of the South African study sites.

“The successes of these cohorts and studies illustrate that, with sufficient funding, collaboration and institutional support, it is possible for researchers in LIMC institutions to build cohorts of indigenous groups and to scale up resources and skills to enable high-quality genomic research in less than a decade,” says Professor Michèle Ramsay, founding member of the H3Africa Consortium and director of the SBIMB.

A roadmap to increase diversity in genomic studies

Despite some notable efforts, representation of underrepresented groups in genetic research remains low. Authors of the paper in Nature Medicine recommend addressing this imbalance by leveraging established local infrastructure and offering strategic funding that is tied to capacity-building.

Specifically, key pillars of the roadmap to set up and sustain diverse global genomic studies include:

  • Stakeholder will (community, researcher, and funders)
  • Infrastructure (computing and biorepositories)
  • Strategic funding (diverse funders, strategic funding calls)
  • Capacity-building (leadership, bioinformatics, exchange programmes, ECR)
  • Global consortia (representative of diverse populations)