Likely human homeland identified

Genetic analysis pinpoints ancient African wetlands.

A vast inland oasis in present-day northern Botswana was once home to the founder population of all modern humans, according to a genetic analysis of modernday Africans published in the journal Nature. The analysis used mitochondrial sequences, which pass from generation to generation through the maternal lineage.

All people belong to a particular haplogroup, as determined by sequences in their mitochondrial genome. Constructing a genetic tree of these haplogroups can tell scientists where different populations first cropped up, and how people dispersed around the world.

The most ancient haplogroup in modern people is L0 (L-zero). The highest frequency of L0 haplotypes is in southern Africa in the Khoe-sān people, indigenous foraging communities who speak language with “click” sounds.

Vanessa Hayes, from Australia’s Garvan Institute of Medical Research, and colleagues homed in on this ancient lineage, pooling more than a thousand L0 mitochondrial genomes from southern Africans to work out where the lineage first arose. “It is a unique region of the world where these pockets still live today in genetic isolation,” says Hayes.

By combining genetic data with climate modelling, the team was able to reconstruct a vivid picture of an ancient human homeland.

According to the analysis, the L0 lineage was born approximately 200,000 years ago, around the same time that a massive prehistoric palaeo-lake twice the size of Africa’s largest lake, Lake Victoria, partially dried into a vast fertile region called the Makgadikgad– okavango wetlands.