(CN) – Africa has long been known as the cradle of life, but the exact location of our evolutionary breakthrough has evaded researchers – until now. In a stunning development, a study released Monday reveals that our ancestral homeland lies buried within an arid region in northern Botswana.
Analysis of fossils of anatomically modern humans suggest our species originated in Africa nearly 200,000 years ago, with the oldest skeletal remains pointing to an eastern African origin.
However, more recent genetic analysis suggests that modern humans first rose in southern Africa.
University of Sydney researcher Vanessa Hayes said in a call with reporters that she and her colleagues set out to find the exact location of the ancestral homeland, the site of our evolutionary milestone.
Through an analysis of more than 1,000 mitogenomes of southern Africans, Hayes said researchers mapped out ethno-linguistic and geographic data to better understand the timeline of evolution in the region.
Residents are classified in the study as KhoeSan – southern African populations with deep histories of foraging and spoken languages containing “click” consonants – and non-KhoeSan, the study said.
The researchers then reproduced ancient climates corresponding to the oldest known fossils from the region in computer models and overlaid with residents’ genetic data.
The analysis revealed that the “founder population” of southern Africans likely rose from the Makgadikgadi–Okavango paleo-wetland in southern Africa, according to the study published in Nature.
Researchers trace the origin of all humans on Earth specifically to a region south of the Zambezi River in northern Botswana, the study said.
Early humans who journeyed to the area came across an enormous, ancient lake in southern Africa that was twice the size of the modern Lake Victoria, located south of Uganda. They adapted to an environment with wet-dry cycles and developed marine foraging techniques – actions that led to steady increases in population, researchers found.
Hayes said in the call with reporters the giant lake would have stretched from modern Namibia and Botswana to western Zimbabwe.
Human settlements were established in the lush, green environment surrounding the ancient lake, where they remained for at least 70,000 years, the study said.
Population levels remained stable in this ancestral, lake-dependent homeland until rising temperatures led to an intense drying out of the region. The lake began to break up about 200,000 years ago, eventually transitioning into a wetland.
Humidity in the region also began to surge, opening once-impassible corridors and creating migration paths away from the drying areas and towards the northeast and southwest of Africa.
“We propose that the southwest migrants maintained a successful coastal forager existence, while the northeast migrants gave rise to ancestral pastoral and farming populations,” the researchers said in the study.
Today, the region is dominated by desert habitats with a number of salt pans sprinkled throughout the area.
Researchers’ summary of the study said these new paths “paved the way for modern humans to later migrate out of Africa, and ultimately across the world.”
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