African genome sequencing reveals migration patterns, viral infection and areas for clinical research

Written by Lauren Woolfe

A recent genome sequencing study has revealed novel insights into the genetic diversity, ancestry and migratory patterns of an African population, as well as illustrated how infections have shaped the genomic landscape of the continent.

Recently, the Human Heredity and Health Consortium (H3Africa) and the National Institutes of Health presented findings from a genomic study at the American Society of Human Genetics 2019 Annual Meeting in Houston (TX, USA). Their large-scale genomic analysis attempted to provide insights on patterns of ancestry among ethnolinguistic groups and illustrate how infections have shaped the genomic landscape of these African populations.

The study group was comprised of 426 individuals, representing 13 African countries and 50 ethnolinguistic groups. Of these, 320 individual’s genomes were analyzed in further detail for rare genetic variants.

Interestingly, the researchers uncovered over three million novel single nucleotide variants (SNVs) within this population, allowing an insight into details of previously unknown migration events, human history and infectious disease exposure and risk.

“We found an impressive breadth of genomic diversity among these genomes and each ethnolinguistic group had unique genetic variants,” commented author, Neil Hanchard (Bayer College of Medicine, TX, USA). “There was a great deal of variation among people in the same region of Africa and even among those from the same country. This reflects the deep history and rich genomic diversity across Africa, from which we can learn much about population history, environmental adaptation and susceptibility to diseases.”

“For the first time, our data from East and West Africa showed evidence of movement that took place 50 to 70 generations ago from East Africa to a region in central Nigeria. This movement is reflected in the genomes of a Nigerian ethnolinguistic group and is distinct from previous reports of gene flow between East and West Africa,” stated senior author, Adebowale Adeyemo (National Human Genome Research Institute; MD, USA). “This data gives us a more complete picture of the genetic history of Africa.”

In addition to SNVs, 33 loci were identified, which are implicated in viral infection and metabolism.

“When you consider which forces have shaped the genetic diversity of Africans, you tend to think of mosquito-transmitted diseases like malaria,” explained Hanchard. “Our study suggests that viral infections have also helped to shape genomic differences between people and groups, via genes that affect individuals’ disease susceptibility.”

Overall, these findings begin to elucidate African heritage and provide a tool for other researchers to utilize in determining how SNVs affect health outcomes.

“It is important to recognize the degree of involvement of scientists from countries across Africa to perform this work, and to raise the profile of African geneticists in all areas of human genetics and genomics research,” concluded Hanchard.

Check out the rest of our coverage from ASHG 2019 here.