Modern-day Botswana has been settled on as the ancestral homeland of all humans alive today, according to a team of researchers.
In a new study published in the journal Nature, scientists said they analysed mitochondrial DNA – genetic information that gets passed down the female line – from more than 1,200 people across myriad populations in Africa.
The researchers said in the study that “Anatomically modern humans originated in Africa around 200 thousand years ago.”
Their findings further stated that “Although some of the oldest skeletal remains suggest an eastern African origin, southern Africa is home to contemporary populations that represent the earliest branch of human genetic phylogeny.”
They came to such a conclusion after examining which genes were preserved in people’s DNA over time. The anthropologists determined that anatomically modern humans emerged in what was once a lush wetland in Botswana, south of the Zambezi River.
Anthropologist Vanessa Hayes, the senior author of the new paper, told journalists that the findings suggest “everyone walking around today” can trace their mitochondrial DNA back to this “human homeland.”
To trace the geographic origin of our ancestors, the scientists examined mitochondrial DNA (mtDNA) from people currently living in southern Africa, such as the Khoisan.
mtDNA, is passed down the maternal line and is often used to trace human ancestry because it isn’t mixed with paternal DNA.
That means it changes less over time and leaves a clearer link to distant relatives.
By pulling on that genetic string, the researchers figured out that every person alive today descended from a woman who lived in modern-day Botswana about 200,000 years ago.
The region this ancestor came from, the Makgadikgadi-Okavango paleo-wetland, was near the modern Okavango Delta and peppered with lakes and greenery.
Until this findings the oldest-ever specimens of anatomically modern humans – skulls and other fossils dating back 195,000 years – were found in Ethiopia.
Based on that many anthropologists concluded that eastern Africa (rather than southern Africa) was the birthplace of our modern ancestors.
The new genetic analysis now however further offers credence to the idea that all modern humans evolved in one place in Africa before migrating to current-day Europe, Asia, and Australia.
Such migration has been known as the “Out of Africa” hypothesis. That defuses the idea that humans evolved separately in multiple places around the world at the same time.