Ancient human fossilsare often found in Africa, but ancient human DNA is scarce.Intense heat and humidity destroy DNA, so ancient fossil DNA is rarely found on the continenthumans came from. But in a new study, researchers reveal that the genomes of living West Africans may hold clues to a mysterious, ancient hominin — a “ghost” human species that currently can’t be identified.The data add another layer of complexity to the story of human history. They also add to our growing understanding of which ancient human species’ genetic signatures remain in present-day African genes — just as modern-d…