The Search for a Cancer Cure Has Ignored African DNA
Charles Rotimi first realized the future was passing him by around 2005. The Human Genome Project had recently finished spelling out an entire set of human DNA. Following that breakthrough, scientists in six countries across the globe had begun collecting blood samples to find genes responsible for various conditions, including serious diseases, which could lead to treatments. And Rotimi, who was leading that collection effort in Africa, had the sick feeling that history was repeating itself.
He wasn’t concerned about himself so much as his homeland. In the past, African patients have had poor access to medical advances, even as scientists use them as research subjects. Rotimi worried that genetics might again exploit the 1 billion people n sub-Saharan Africa, ignoring their need for treatments for HIV, tuberculosis, malaria and cancer. “The genomic revolution was going to fly over Africa,” he says, “and tomorrow’s medicine will not work for all.”
His concern was well founded. Over the next few years, scientists came out with a frenzy of discoveries about our DNA that could possibly lead to new treatments for diabetes, cancer, psychiatric illnesses and other serious diseases. But they were drawing from a small slice of the world: Nearly all of the published work was based on populations with European ancestry. By 2009, fewer than 1 percent of the several hundred genome investigations included Africans.
The genomics revolution soon began to sputter. Being able to know the exact genetic makeup of each patient was to bring a new era of treatments tailored for each individual. But doing so depends on finding minute variations in our DNA that correlate with the occurrence of disease or bad drug reactions. This task requires the full range of genetic variation among as many humans as possible. Otherwise, genomics research is like a search party that circles the same few trees looking for signs of the killer rather than spreading out through the entire woods.
The richness of African genomes is a product of the evolution of our species. Modern Homo sapiens originated in Africa about 200,000 years ago. About 100,000 years later, 1,600 or so men and women—from a population of at least 20,000 and likely much more—left the continent and spread around the globe, eventually reaching Europe and, more recently, the Americas. “In other words,” wrote
