Sequence of African genomes for Africa and the world: scientific

A $ 4.5 billion initiative to track the genomes of three million Africans will not only benefit a continent that has long been neglected in genetic health care, but also advance the understanding of genetic diseases worldwide, the project leader said on Wednesday. AFP said.

Twenty years ago this month, the first complete mapping of the human genome was published after a marathon of more than ten years that took hundreds of scientists and cost three billion dollars.

This groundbreaking effort has revolutionized medicine and led thousands of so-called genome-wide association studies (GWAS) to shed light on the role that genes play in a variety of diseases, conditions and treatments.

Today, the cost of sequencing a genome to a similar level of precision is less than $ 1,000.

But the continent from which mankind originated has lagged behind in this giant leap and remains a genetic slate compared to Europe or the United States.

“Most genomic research on the African continent over the past two decades has been largely driven by agendas that are more defined by European and American researchers,” said Ambroise Wonkam, a professor of medical genetics and deputy dean of research at the University of Cape Town. Faculty of Health Sciences. , told AFP.

The genomes of more than a million individuals have been traced so far, but less than two percent were from Africa or of recent African descent.

This is despite the fact that the continent has far more genetic diversity than any other region in the world – a diversity that would yield huge research dividends if exploited and mapped.

“The Three Million African Genomes (3MAG) project requires individuals selected across Africa to be evaluated to cover ethnolinguistic, regional and other groups,” Wonkam said.

“The aim is to capture the full extent of Africa’s genetic variation – to the benefit of all human populations and to ensure equitable access to genetic medicine.”

An incomplete ‘reference genome’

Wonkam stated his case in a comment published in the magazine on Wednesday Nature, arguing that the different gene pool of Africa will make it easier to identify mutations that are likely to cause or contribute to a specific disease or condition.

A variant, for example, of the PCSK9 gene that has only become apparent because it is 200 times more common among African Americans than Europeans, correlates with much lower levels of certain blood lipids.

This finding has led to new medications for a blood condition associated with heart failure and stroke, called dyslipidemia, that are affecting populations worldwide.

“The inclusion of even a small number of black Americans in control groups would probably have caused the misclassification of benign variants as cardiomyopathy,” prevented a disease that attacks the heart muscle, Wonkam said with another example.

The relatively few GWAS of African populations done also showed a genetic susceptibility to type 2 diabetes that was not previously reported.

A lack of genetic data from the continent also obscures the influence – good or bad – of certain mutations on treatments.

For example, up to half of the African population carry a gene variant associated with serious side effects on the HIV drug efavirenz, which can cause virus resistance when patients skip doses.

When scientists recently sorted the genomes of 910 people of African descent, it appears gaping holes in the so-called “reference genome” used by researchers around the world, said Jesse Gillis, a researcher at the Stanley Institute for Cognitive Genomics in New York, noted in a study in BMC.

“About 10 percent of the DNA sequences – about 300 million base pairs – are missing from this genome,” he said.

Wonkam said that funding should come mainly from African governments, but that international organizations should also start.

© 2021 AFP