Genetics help unravel history

FRENCH researchers have taken a large step towards unravelling the origins of South Africa’s first Bantu-speaking people.

In a first- of- its- kind study, Etienne Patin and a team of researchers from the Pasteur Institute in Paris used genetic analysis to track the migration across Africa 5 000 years ago of Bantu speakers from the region between Nigeria and Cameroon. Today, about a quarter of Africa’s billion people, including many black South Africans, speak a Bantu language.

Long-standing archaeological and linguistic evidence already showed where Bantu speakers originated.

This study pointed to the path some took to get to South Africa, while also revealing survival traits they picked up on their journey and the extent to which they mixed with the Ju/’hoansi San people as they approached the continent’s edge.

“(Our) result supports the view that the first step of the Bantu expansion was a movement from the Nigeria/Cameroon frontier to Gabon and Angola across the equatorial rainforest, followed by movements towards eastern and southern Africa,” Patin said.

The researchers started by taking genetic samples from Bantu people in Cameroon, Gabon, Angola, Uganda, Kenya and South Africa. Every person contains variants of certain genes, many of which are shared across a specific population.

Researchers compared the South African and Ugandan samples to the genes of the Bantu speakers in the Nigeria-Cameroon border region.

The further they migrated away from the original population, the more they mixed with local peoples and the more their genes began to differ. When researchers found Bantu speakers in southern and eastern Africa shared more variants with the original speakers, they could deduce the Bantu migration started in that direction.

In other words, Bantu people came to South Africa pretty early on in the migration.

In analysing the genetic data, the researchers discovered that to the extent that present day Bantu speakers can drink milk, they can owe it to the local population the migrants encountered on their journeys.

The original Bantu population were lactose-intolerant, but researchers found they picked up the genetic variants for tolerance – and malaria resistance – as the migration progressed.

Patin said the study was one step toward helping understand the overall genetic diversity of people from the African continent, a task with numerous health implications.

The African Genome Variation Project and other labs are now constructing a clear map of the genetic diversity across Africa, what call Patin calls “an enormous task”.