Ancient human DNA recovered from the oldest cemetery in Africa
Museum archaeologists were part of an international team uncovering clues to the people who lived in North Africa 15,000 years ago.
They examined the DNA of human bones from the oldest cemetery in Africa, in the depths of Grotte des Pigeons cave, near Taforalt in Morocco.
'The cave is a crucial site in understanding the human history of northwestern Africa,' says Dr Louise Humphrey, Researcher in Human Origins at the Museum, who has been excavating the site since 2004.
The results show that the people shared genetic ancestry with populations from both the Near East and sub-Saharan Africa, but not from Europe.
'This is the first and the oldest DNA of our species recovered in Africa,' explains Abdeljalil Bouzouggar from INSAP (Institut National des Sciences de l'Archéologie et du Patrimoine) in Rabat, Morocco.
Puzzling out the population of North Africa
Tracing how humans spread in the ancient world is no small feat.
Sometimes a change in the archaeological record is caused by populations migrating and bringing their culture with them - other times it is the exchange of new ideas and technologies rather than migrating people.
The genetic history of the ancient people who lived in North Africa is a puzzle. Because they are both on the African continent and part of the Mediterranean region, their barriers are twofold: the Sahara Desert to the south and the Mediterranean Sea to the north, both of which will have often hindered population movements, depending on climate.
While we know that present-day North Africans share a majority of their ancestry with present-day Near Easterners, and less so with sub- Saharan Africans, we do not know when the connection would have first happened.
Challenging environmental conditions in many parts of Africa mean that ancient DNA is poorly preserved.
'Relatively few ancient genomes have been recovered from Africa and none of them so far predate the introduction of agriculture in North Africa,' explains Marieke van de Loosdrecht of the Max Planck Institute for the Science of Human History in Jena, Germany, and lead author on the study.
The oldest cemetery in Africa
Grotte des Pigeons is a rich resource for archaeologists - modern humans have left behinds traces of their visits to the cave over at least 100,000 years.
The appearance of a distinctive type of finely made stone tools known as microliths about 22,000 years ago represents a change in culture and may indicate a new population migrating to the region.
Around 15,000 years ago, the inhabitants changed their lifestyle. Although they were still hunter-gatherers rather than settled farmers, they increasingly used the cave to build fires and cook an expanded diet.
They also started to use the back of the cave as a burial site, making it the oldest cemetery found in Africa. It is from these buried bones, taken from seven different individuals, that the DNA was extracted for the study.
Early population connection
The researchers found that the people living in the cave 15,000 years ago had two major components to their genetic heritage. About two thirds are related to populations who lived at the same time in the Near East. The other third is most similar to sub-Saharan Africans, in particular West Africans.
The results show that the connection between North Africa and the Near East began much earlier than many previously thought, and the Sahara was not an impassable barrier.
'Clearly, human populations were interacting much more with groups from other, more distant areas than was previously assumed,' concludes Prof Johannes Krause from the Max Planck Institute for the Science of Human History, where the DNA analysis was performed.
Further studies in this region could shed more light about where these different populations came from, and when and how they interacted.