Excavation in 1994 that found the skeletons of two boys buried around 8,000 years ago. Photo Credit: Isabelle Ribot

The study of four children – two of whom were buried approximately 8,000 years ago and two 3,000 years ago – from Shum Laka, Cameroon has revealed new insights into how Africa was populated. 

Published in Nature, the researchers found that at least three major human lineages diverged genetically from each other in rapid succession between 250,000 and 200,000 years ago, being ancestral to either today’s central African hunter-gatherers, southern African hunter-gatherers or all other present day people. The study also found a previously unknown fourth population that emerged during that time span and left a genetic mark on modern western and eastern Africans, with parts of their DNA coming from hominid populations present before modern humans, possibly from Neanderthals.

It’s believed that the present-day border between Cameroon and Nigeria was where the Bantu language group originated, and where the descendants from these populations spread out across the southern half of Africa and created the vast range and diversity of the Bantu languages today. This Bantu expansion can explain why most people currently from those regions have close genetic connections.

The four children were found during excavations in the 1980s and 1990s at Shum Laka, a rock-shelter in north western Cameroon.

A previous study at the Francis Crick Institute, UK found a human population that originated more than 200,000 years ago and was ancestral to later hunter-gatherer groups in western and central sub-Saharan Africa. The four ancient children were found to carry some ancestry from that ancient population.

They also found that the ancient children are not closely related to current Bantu speakers. Around two-thirds of their DNA was closely related to a previously unknown population distantly related to present-day West Africans. The rest came from the lineage discovered in the other study linked to central African hunter-gatherers. Bantu speakers and present-day central African hunter-gatherers show different ancestries from each other.

This new study shows that current Bantu speakers didn’t descent from the Shum Laka population, but from other populations that lived in west-central Africa around the same time.

One of the Shum Laka children buried around 8,000 years ago carried the Y haplogroup A00, an extremely rare set of gene variants which hasn’t been seen in other ancient DNA samples and dates back to 200,000 and 300,000 years ago. Today, this lineage is only found in two ethnic groups in western Cameroon.

Analysing the children from Shum Laka and other ancient individuals can help give insights into the early populations of Africa and help understand the complex genetic diversity of this region.