In studies that embrace the increasingly controversial Out of Africa Hypothesis, the Yoruba are frequently assumed to be the African ancestor of non-African groups. This includes all people of Eurasian, Native American and Aboriginal Australian ancestry.
But where did the Yoruba people come from, and what is their genetic background?
Researchers led by Josh Akey of Princeton University have spent years sequencing and analyzing the genomes of contemporary Africans who come from populations with extensive ancestry, including the Yoruba from Nigeria.
Remarkably, they discovered portions of DNA in these genomes that resemble those of an African Neanderthal, or another hominid species.
Geneticists speculate that this ghost species interbred with Homo sapiens following the out-of-Africa migration 60,000 years ago, because this DNA is exclusively present in the descendants of African people, and not in any Eurasians.