Treasure trove in Africa’s roots
Researchers are plotting Africans’ DNA to delve into humanity’s earliest origins
SHAUN SMILLIE
ACROSS Africa lies a treasure trove that is helping in the fight against disease and telling the story of our earliest origins.
This treasure is carried in the cells of every living African, but only recently have scientists begun unlocking its secrets.
The double helix of DNA and Africa have become the next frontier in genetic research.
Humans originated from Africa, and this makes Africans unique when compared to other populations.
“We (Africans) are the first populations of modern humans and, by studying our DNA, this will inform what is happening in the other populations. So, there is a gap in what we know about human genetic variation and data from Africa can close this gap,” said Dr Michelle Skelton of the University of Cape Town, who is part of the Human Heredity and Health in Africa (H3africa) Administrative Co-ordinating Centre.
H3africa is a health and genomics research consortium that spans 32 countries and includes 48 projects. The initiative began in 2012.
“The rest of the world is actually populated by a sub set of people who came from Africa and migrated out of the continent in several waves from roughly 70 000 years ago,” said Professor Michele Ramsay of Wits University, who is also involved with H3africa and leads a large, collaborative centre in a study on cardiometabolic disease (including obesity, hypertension and diabetes) across four African countries, with more than 12 000 participants.
“You can see why the whole world would be interested to understand what aspects of African genetics variations they see in their populations.”
Slowly, more and more genetic research is happening across Africa. At a recent conference in San Diego in the US scientists presented their findings in what is one of the largest sets of African genomic data available to date.
Researchers collected and analysed genomic material from 6 400 individuals in Uganda, which was then combined with that of 7 784 people from other African countries.
“This study represents one of the largest and most comprehensive efforts to identify genetic associations with disease within African populations, and will provide a roadmap for largescale genome-wide association studies across the region,” Dr Ayesha Motala, a leader of the study and professor at the University of Kwazulu-natal, told the conference.
This research has allowed some insight into the complex history of migration in east Africa, which has continued for thousands of years.
But besides following the paths of ancient migratory routes, genetics is providing insight into diseases and how they affect different populations.
“What we want to understand is the relationship between genetic variation and disease,” said Ramsay.
“We want to look at the people who are living now to understand how genetic variation has developed over tens of thousands of years and how it makes people more or less susceptible to particular diseases or traits.”
Some of the diseases are old, like malaria and TB infections, while others such as diabetes are associated with obesity, a modern-day pandemic that is beginning to gain a foothold on the continent.
There is a study of how obesity is affecting populations in west Africa,
This genome chip has been specifically designed for Africa
Dr Michelle Skelton UCT DNA researcher
east Africa and South Africa.
But working in Africa does have its challenges. There are cultural issues to deal with, especially developing an appropriate vocabulary to explain genetics and genomics to communities, cultural implications where blood might have to be taken as part of the study and requesting consent for future use of data and samples. Policies had to be drawn up to deal with such ethical issues.
Then there is also the logistics of dealing with different countries and institutions. Skills are also a problem and therefore capacity development is a priority. But ultimately, the plan is to collect more samples across the continent.
What will help in analysing large quantities of samples in order to collect genetic data is a genome chip that has been developed by H3africa.
“This genome chip has been specifically designed for Africa, to detect specific genetic variations that are unique to Africans.
“We will now be able to look at bigger populations by just scanning the genome using this chip,” said Skelton.