A single ‘garden of Eden’ location where humans are believed to have originated has been discovered in Africa.
DNA analysis has identified the “cradle of mankind” for our ancient ancestors was in Botswana in the middle of the south of the continent.
The area, which is now dominated by desert, was then abundant wetlands. Experts had previously thought our species evolved all over Africa.
Our ancient ancestors originated just south of the Zambezi River once home to an enormous lake similar in size to England, called Lake Makgadikgadi.
The lake stretched all the way from Namibia, across Botswana and into Zimbabwe. As it began to break-up a vast wetland was created providing a lush home abundant with plants and trees for our earliest relatives.
It was here early humans thrived for 70,000 years until the climate changed and they were forced to leave Africa to populate the rest of the planet.
Vanessa Hayes, of Sydney University, said: “It has been clear for some time anatomically modern humans appeared in Africa roughly 200,000 years ago.
“What has been long debated is the exact location of this emergence and subsequent dispersal of our earliest ancestors.
“This [study] enabled us to pinpoint the ancestral homeland of all humans. It is the first time the exact location has been identified.”
The international team collected blood samples from study participants in Namibia and South Africa and looked at their mitochondrial DNA (mtDNA).
As mtDNA is passed almost exclusively from mother to child through the egg cell, its sequence stays the same over generations, making it a useful tool for looking at maternal ancestry.
The study published in the journal Nature focused on the L0 lineage - modern human’s earliest known population.
Prof Hayes added: “The first migrants ventured north east, followed by a second wave of migrants who travelled south west.
“A third population remained in the homeland until today.”
“Mitochondrial DNA acts like a time capsule of our ancestral mothers, accumulating changes slowly over generations.
Her international team collected blood samples from 1,217 people to establish a comprehensive catalogue of the ‘L0’ lineage.
It comes two years after a study suggested Homo sapiens emerged all over Africa simultaneously and not in one place.
Researchers said the success of the first humans came from learning how to scoop up seafood, including fish, with their hands.
Climate computer models were also used to simulate South Africa’s climate history over the past 250,000 years.
Author Prof Axel Timmermann, of Pusan National University, South Korea, said: “They suggest the slow wobble of Earth’s axis changes summer solar radiation in the Southern Hemisphere, leading to periodic shifts in rainfall across southern Africa.
“These shifts in climate would have opened green, vegetated corridors, first 130,000 years ago to the northeast, and then around 110,000 years ago to the southwest, allowing our earliest ancestors to migrate away from the homeland for the first time.”
Fossil finds had hinted at modern humans originating in East African, whereas genetic analyses suggested they arose in South Africa.