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By Tebogo Monama 
3h ago
New research by African geneticists has given them insight into how migration has changed DNA and protected Africans from disease and viruses.
Researchers have identified about 62 genes associated with viral immunity, DNA repair, and metabolism in Bantu-speaking populations.
The study analyzed complete genomes of 426 individuals from 13 African countries, whose ancestry represents 50 ethnolinguistic groups from across the continent. It was published as a cover article in the journal Nature.
The study was led by Wits University Human Genetics Division Professor Zané Lombard under the auspices of the Human Health and Heredity Consortium in Africa (H3Africa) in association with Dr. Neil Hanchard and Dr. Adebowale. Adeyemo. Members of the H3Africa Consortia who contributed to this work include researchers from 24 institutions in Africa, including the Sydney Brenner Institute for Molecular Bioscience (SBIMB) at the Wits University School of Health Sciences.
They observed complex patterns of ancestral mixing within and between populations, along with evidence that Zambia was a likely intermediate site along the routes during migrations more than 2,000 years ago.
“We know that populations, many thousands of years ago, moved from West Africa, the Chad region, Nigeria, to eastern, central and southern Africa. What this data shows us now is that the most likely based on the signatures that we see in different people living in these countries now is that that movement probably occurred through Zambia.
“One of the things we know is that there is a large rainforest that separates West Africa from the southern part. Moving and migrating through that area was not always clear and these genetic data show us similarities between the different groups currently living in West Africa and those in Zambia, ”Lombard said.
They also found genomes that could be helping Africans fight disease. SBIMB’s Dr Dhriti Sengupta and one of the lead analysts said they found more than 100 areas of the genome that had likely been under natural selection; a considerable proportion of which were associated with genes related to immunity.
“While it has long been known that genes involved in resistance to insect-borne diseases such as malaria and sleeping sickness are selected positively, our study shows that viral infections may also have helped shape genomic differences between people and groups by altering the frequency of genes that affect people’s susceptibility to disease.
“There were notable variations in selection signals between different parts of the continent, indicating that large-scale local adaptations may have accompanied the migration of populations to new geographies and subsequent exposure to new diets and pathogens,” Sengupta said.
Lombard said more research on genomes is still needed. “We have not been able to link them to specific diseases or outbreaks. What we can see is that they are linked to genes that influence the way we metabolize food. What we are thinking is that those people migrated from specific regions and their diets may have changed. They could have gone from being hunter gatherers to domesticating animals.
“We need to explore the immune factor more. What we can do now is go back to the communities and investigate the history and start looking at the genes and linking them to epidemics and viral infections that occurred in the history of that country and start learning which genes are important for immunity and resistance. ” Lombard said. He said.
He said the research being done by geneticists on the continent was important in removing historical bias. “Africa is the continent with the greatest genetic diversity and this study shows the importance of African genomic data in advancing scientific and health research. It is an important step to correct existing biases in the data available for research, which hamper the study of African health problems and restrict global research, ”he said.
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