First ancient human genome from Africa is sequenced

DNA from the skull of an ancient human buried in an Ethiopian cave for about 4,500 years reveals the history of early Africans who originated from the Middle East. The latest discovery suggests that Africa was more connected to larger portion of the world thousands of years ago.

Previously, scientists had only been able to sequence DNA from samples found in northern and arctic regions, because the climate there allows genetic material to survive for longer.

The findings were reported in the journal Science.

When the ancient genome was compared with DNA of modern Africans, it was found that not only East African populations but people from the all corners of the continent are closely related to Western Eurasians.

But this study shows that about 3,000 years ago there was a much larger migration than had been thought.

Previous work on ancient genetics in Africa had involved trying to work back through the genomes of current populations, attempting to eliminate modern influences. “One genome from one individual can provide a picture of an entire population”, said Manica.

The cause of the West Eurasian migration back into Africa is now a mystery, with no obvious climatic reasons. And archaeological evidence shows that this migration occurred at the same time as the introduction into Africa of Near Eastern agricultural crops, such as barley and wheat.

Commenting on the research, Dr Carles Lalueza-Fox, from the Institute of Evolutionary Biology in Barcelona, Spain, said: “What is nice is that it places in time the origin of the Eurasian backflow into Africa already detected a few years ago from modern genome data, and it turns out to be the farming”.

Africa is considered the cradle of human genetic diversity, the place from which humans spread across the globe.

“Africa is a total melting pot”.

It’s clear that there was a substantial movement of people back to Africa around 3000 years ago, but we know little about how many made the journey – or why. “So being able to get a snapshot from before these migration events occurred is a big step”, Gallego Llorente said.

Most people are familiar with the idea that there was a migration of early humans who moved out of Africa to colonise Europe and Asia between 60,000 and 125,000 years ago.

Furthermore, the man had brown eyes, dark skin, and genetic characteristics suitable for living at high altitudes.

This migration and its timing has now been confirmed after the successful copying of a full genome from the skeleton in the Mota Cave in the Ethiopian highlands. Ron Pinhasi from University College Dublin, Ireland, and his colleagues discovered that it was possible to get very high DNA yields from the petrous portion of the temporal bone, the densest bone in the mammalian body – as much as 500 times that from other bones.

However, the 4,500-year-old remains of this hunter gatherer, known as Mota man, were found in a cave and were well preserved.

The genetic impact of the migrants was much greater in east Africa, where the DNA of today’s populations are up to 25 per cent derived from the migrants.