“Welcome home!” » welcome home 14’s themee The International Congress of Human Genetics (ICHG), organized every five years, was not chosen at random: for the first time, conferences of experts in this young field took place at the end of February in Africa, Cape. A strong symbol and “A way to remember that we are all Africans”World-renowned expert and President of the Society of African Human Genetics (SAfGH), organizer of the event Prof. Ambrose Wonkam explains.
However, since the publication of the first complete sequence of the human genome, twenty-two years ago, less than 2% of all cataloged genomes have come from people of African descent. A paradox, at the same time “The vast majority of human genetic diversity is continental, The Cameroonian researcher who is also the head of the Department of Genetic Medicine at the Johns-Hopkins University in Baltimore (Maryland) states. Each African genome is estimated to have five times more variation than the Caucasian genome. » With the liberation of AfricaHomo sapiens By 50,000 to 60,000 years ago, only a small sample of genetic diversity had spread around the world.
Most of the studies carried out over the past two decades have been carried out by European and American groups. “The researchers worked with genes that were more accessible, so mainly from people of European descent. But the genomes of African populations show much greater diversity than that of Caucasian genomes. Adds Hughes April, professor of molecular medicine at the University of Bern, Switzerland.
In recent years, if researchers’ interest has extended to Asian populations, Africans are largely forgotten. with more concrete implications for improving the diagnosis and management of genetic diseases on the continent. ” As a medical geneticist, when I sequence the genome of a sick child and I find an anomaly, the available databases do not help me because they only contain information from people of European descent. Shahida Musa, Head of the Department of Genetic Medicine at Tygerberg Hospital and Professor at Stellenbosch University in Cape Town. There is therefore an urgent need to sequence DNA on the continent to build an African genome library.
A scientific need, an equity issue
Because a genetic variant can change the symptoms of a disease, sometimes for the same disease, it is different from the known gene in the Caucasian genome in question. ” A mutation often seen in Western children born deaf has never been found in Africa. The legendary Ambrose Wonkam. On the other hand, we identified seven new genes associated with hearing loss in Ghana. »
Identifying these variants and improving knowledge about the genomes and genetic diseases of African populations is not only a scientific need but also an equity issue. ” When I started my project Cystic fibrosisI discovered that in the Democratic Republic of Congo, out of 100 million people, not a single case is officially registered!, The author informs Hughes April collaborates on several projects across the continent. However, we know from small cohorts that the disease also exists in Africa. »
When she applies for funding, Shahida Musa is often told that rare diseases and human genetics projects in Africa are not a priority. “Yes, HIV, tuberculosis and malaria are rampant here, but we need to stop working in silos and resisting the problems.she says. A better understanding of the human genetics of African populations will have benefits beyond rare diseases! Genetics has made it possible to make progress in many diseases, especially infectious and chronic. »
To support his colleague’s opinion, Ambroise Wonkam recalls that the latest drugs developed to treat excess cholesterol, and used mainly in high-income countries, come from studies carried out on variants of the PCSK9 gene. Very common in some African populations, but rare in people of European descent.
Increase local search capabilities
The experts interviewed therefore emphasize the universality of the benefits to be derived from better knowledge of African genetics, but also the need for locally conducted research. “We no longer want to do “helicopter research” by experts who leave the continent for a few months.Shahida Musa asserts. Researchers from here are used by some foreign colleagues and retain this mistrust that today mars collaboration between African teams. However, we must network if we want to move forward. »
project Human heredity and health in Africa (H3Africa), which has just been completed, has made it possible to train many young African scientists in genetic sciences over ten years. ” We hope to be able to follow up this great project by establishing centers of excellence in genetics on the continent, but discussions are ongoing with potential donors, so I cannot say more. Professor Ambrose Wonkam cautions.
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For many years now, African and European universities have developed close ties to ensure the enhancement of local research capacities. Thus the cooperation between Guild of Research and the Alliance of African Research Universities (Arua), thereby seeking to implement this work “African Clusters of Excellence”, explains Guild member Hughes April. Ambrose Wongham explained in a recently published edition Nature, approximately 3 million genomes will need to be sequenced over the next ten years to create a well-stocked library. The ambition required $450 million a year.
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