Johannesburg - In the genes of some of Africa’s oldest populations is not just the story of our most ancient past but also a future of new discoveries that could save lives in generations to come.
A new genomic study of 180 Africans from across the continent, including members of the San in southern Africa has provided one of the most complete pictures of human origins and local adaptation.
An international team of researchers through this genomic work were able to not only take a peek into human migrations of the past but also see the genetic adaptations to local environments through traits such as skin colour, heart and kidney development, immunity, and bone growth.
The findings of this research was published in the journal Cell and was led by University of Pennsylvania researchers, in the US.
They believe that this could have an impact on modern populations in helping understand health conditions common in people of African ancestry.
“There is a lack of knowledge about genomic variation in African populations, particularly in ethnically diverse populations,” said the lead author of the study Professor Sarah Tishkoff, of University of Pennsylvania, in a statement. “We focus on populations who practice more traditional lifestyles, live in remote areas that can be difficult to access, and some of whom have never been studied from this perspective before.”
The researchers were able to obtain the complete genome sequences for 180 individuals of which 15 came from each of the 12 indigenous populations.
By allowing for gene flow in their models the team was able to craft a worldwide family tree. At the root of this tree they discovered the southern African Khoisan-speaking group, the San, and the Central African, rainforest-dwelling hunter-gatherers
“That’s a very novel result,” Tishkoff explained. “Previous analyses had pointed to only the San as descending from the most ancient populations.”
They further found that the San and Central Africa hunter-gatherer groups split from one another more than 200,000 years ago. It is believed that both groups might have originated from East Africa.
Their research also suggested evidence of a now extinct ghost population that might have intermixed with other groups in the past.
By examining the genetics of these various groups, scientists have been able to track disease susceptibility.
“Comprehensively assessing genetic variants has been used as a strategy to study human disease and provides tremendous power to identify new loci associated with disease susceptibility and progression,” said Sununguko Wata Mpoloka of the University of Botswana.
“Including understudied indigenous populations like those from Botswana in such studies will contribute tremendously to an understanding of precision medicine and could lead to tailor made drugs specific to such populations.”
In the future picking apart the genes of individuals that belong to our most ancient lineages could even help in preventing heart attacks.
“My lab is now following up with some of these genes to see whether we can learn about the genetics of heart muscle development,” said Tishkoff. “If we understand how these genes are regulated, that could give us a clue as to why some people have a tendency toward cardiovascular disease.
To understand abnormal function, you first have to understand normal function, and we speculate that there’s something about these individuals’ lifestyles—having to walk incredibly long distances, for example—that might make it advantageous to have certain changes in how the heart develops and functions.”