Dr Ambroise Wonkam carries hundreds of thousands of years of history in his blood. The impacts of pathogens, migration, environment and geography are written into the braids of DNA he inherited from tens of thousands of generations of ancestors. This richness, he remarks, is not unique. It is a shared legacy for more than one billion people: in South Africa, where he works; in Cameroon, where he is from; and across the African continent – the most genetically diverse landmass on earth. With such wealth all around him, how could he not spend his life studying it? Wonkam is one of several scientists from Africa who made significant gains in 2020 towards understanding diseases that affect millions – and are not novel pandemic viruses. He and others lead large experiments that analyse whole genome data from thousands of African volunteers in South Africa, Ghana, Nigeria and beyond. The knowledge these scientists are collecting is broadening humanity’s reference genetic archive, the libraries scientists around the world use to identify and compare genomic information. It is filling in blind spots in a field that has been dominated for a generation by institutions in the Global North and in data that has historically not included African participants. Despite lockdowns and working from home, 2020 was a productive year for Wonkam and his peers. The power of place Humans diverged from chimpanzees 5 to 6 million years ago in East Africa. Modern humans appeared just 300,000 to 200,000 years ago, and some time after that (about 100,000 years ago, though the evidence is still being interpreted), our species started migrating beyond Africa, probably over several attempts. As we walked, humans homogenised, sharing traits, discarding others and becoming more similar the further we went. “We are all African,” Wonkam said from Cape Town. “But ancestral Africans, like me, who have stayed on the continent for a very long time, have at least 300,000 years of human genetic history in their blood, which makes the variation in the African population thousands of times higher than in any other populations in the world.” When presented on a chart, the data shows the exodus effect: a plot of genetic diversity among humans against distance from East Africa looks like a slender, almost 45-degree line sloping downwards, through the Middle East, Europe, Asia and, finally at the tail end, the Americas, where populations tend to be the most genetically similar. Africa’s rich, varied dataset is attractive to scientists, and also to companies and health institutes abroad. Over the years, several have exploited lax patient privacy laws and left scandal and mistrust in their wake. A drug company settled a high-profile lawsuit after running trials that were poorly explained to its African participants; one health technology company shut down a product after a whistle-blower revealed it would be sold against the agreements of volunteers whose data was used to produce it; and during and after the West Africa Ebola epidemic, certain European governments we