It is generally accepted by scientists that modern humans, also known as Homo sapiens, migrated out of eastern Africa around 200,000 years ago. But a new genetic study suggests that our origins lie in the southern region of Africa that includes Botswana, thus giving racists something else to cry about.
Several years ago, a white supremacist named Craig Cobb submitted himself voluntarily to a DNA test because he was absolutely certain that he had “pure” white blood. The problem with believing such things is that most humans on the planet will find that a percentage of their DNA traces back to Sub-Saharan Africa. In Cobb’s case, his DNA showed that he is 14 percent Sub-Saharan African. Thus, a white man who believes himself superior to black people found out on national television that he is not as white as he thought.
And that is the case for many other white supremacists, who resort to disputing the science and explaining away the results in a ridiculous fashion so that they can hold on to their racist worldview.
When humans migrated out of Africa, those who migrated to Europe found themselves in a place that receives less sunlight, and scientists hypothesize that skin color evolved as a result because paler skin absorbs more vitamin D. That doesn’t mean white skin is somehow superior to darker skin, it just means the skin of this population of humans adapted to the environmental conditions over time.
So, we know that humans originated in Africa. Now the question is exactly where?
A new study conducted by a team of researchers, which has been published in the journal Nature, suggests that humans lived for 70,000 years in southern Africa in an area comprising Botswana, Namibia, and Zimbabwe.
Noting that the oldest Homo sapien skeletal remains have been found in Africa, the team proposed a different region of origin based on DNA studies.
According to the study:
Anatomically modern humans originated in Africa around 200 thousand years ago. 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. Here we generate, to our knowledge, the largest resource for the poorly represented and deepest-rooting maternal mitochondrial DNA branch (198 new mitogenomes for a total of 1,217 mitogenomes) from contemporary southern Africans and show the geographical isolation of descendants south of the Zambezi river in Africa.
The possibilities associated with such a study in this region have long been overlooked or ignored by scientists, which means alternative hypotheses have not been able to gain much traction. But this research may overturn centuries of debated science on its head.
During that 70,000 years, humans thrived until periods of climate change forced them to migrate elsewhere.
By establishing mitogenomic timelines, frequencies and dispersals, we show that the lineage emerged within the residual Makgadikgadi–Okavango palaeo-wetland of southern Africa…Genetic divergence points to a sustained 70,000-year-long existence of the lineage before an out-of-homeland northeast–southwest dispersal… Palaeo-climate proxy and model data suggest that increased humidity opened green corridors, first to the northeast then to the southwest. Subsequent drying of the homeland corresponds to a sustained effective population size, whereas wet–dry cycles and probable adaptation to marine foraging allowed the southwestern migrants to achieve population growth, as supported by extensive south-coastal archaeological evidence. Taken together, we propose a southern African origin of anatomically modern humans with sustained homeland occupation before the first migrations of people that appear to have been driven by regional climate changes.
University of Sydney Garvan Institute of Medical Research professor Vanessa Hayes, who led the study, said in a statement that the research pinpoints the birthplace of modern humans and should help settle a debate that has dragged on for a long time.
“It has been clear for some time that anatomically modern humans appeared in Africa roughly 200 thousand years ago,” Hayes said. “What has been long debated is the exact location of this emergence and subsequent dispersal of our earliest ancestors. Mitochondrial DNA acts like a time capsule of our ancestral mothers, accumulating changes slowly over generations. Comparing the complete DNA code, or mitogenome, from different individuals provides information on how closely they are related.”
Hayes’ colleague, Dr. Eva Chan, explained that the team gathered rare DNA codes for the study.
“We merged 198 new, rare mitogenomes to the current database of modern human’s earliest known population, the L0 lineage,” Chan said. “This allowed us to refine the evolutionary tree of our earliest ancestral branches better than ever before.”
University of Pretoria health professor Riana Bornman pointed out that the new DNA samples gave them access to a new part of the Homo sapien family tree.
“Our work would not have been possible without the generous contributions of local communities and study participants in Namibia and South Africa, which allowed us to uncover rare and new L0 sub-branches,” Bornman said.
Making the region an even better candidate for human origins is the fact that it was a lush landscape with plenty of water, as Rhodes University geologist and study author Dr. Andy Moore pointed out.
Indeed, that lake is now known as Lake Makgadikgadi, and it dried up in what we know now as the Kalahari Desert.
“Prior to modern human emergence, the lake had begun to drain due to shifts in underlying tectonic plates,” Moore said. “This would have created, a vast wetland, which is known to be one of the most productive ecosystems for sustaining life.”
But around 130,000 years ago, even this lush paradise became a nightmare environment for humans, forcing them to undertake a mass migration in waves as the land started to dry up.
“We observed significant genetic divergence in the modern humans’ earliest maternal sub-lineages, that indicates our ancestors migrated out of the homeland between 130 and 110 thousand years ago,” Hayes said. “The first migrants ventured northeast, followed by a second wave of migrants who traveled southwest. A third population remained in the homeland until today. In contrast to the northeasterly migrants, the southwesterly explorers appear to flourish, experiencing steady population growth.”
As we are experiencing today, the human population in southern Africa migrated because of climate change. Unlike the current climate change, however, this climate change was a naturally occurring event caused by a shift in Earth’s axis.
Professor Axel Timmermann, Director of the IBS Center for Climate Physics at Pusan National University, ran simulations to hypothesize that this event occurred twice and opened up pathways allowing groups to travel away from their homeland to make better lives somewhere else.
“Our simulations suggest that the slow wobble of Earth’s axis changes summer solar radiation in the Southern Hemisphere, leading to periodic shifts in rainfall across southern Africa,” Timmermann said. “These shifts in climate would have opened green, vegetated corridors, first 130 thousand years ago to the northeast, and then around 110 thousand years ago to the southwest, allowing our earliest ancestors to migrate away from the homeland for the first time.”
But not all left the region. Some elected to stick around, resulting in the population that still exists there to this day.
“These first migrants left behind a homeland population,” Hayes concluded. “Eventually adapting to the drying lands, maternal descendants of the homeland population can be found in the greater Kalahari region today.”
Of course, as climate change yet again rears its ugly head, it’s having an even greater negative impact on already arid regions, making them even hotter and more inhospitable to life. Perhaps a third wave of migration from the region is in the cards sometime in the near future, resulting in our ancient homeland being totally devoid of humans for the first time in over 200,000 years.
For the ancient astronaut take on this news see: Ancient astronaut theorists take note as scientists trace ancestral home of all humans to southern Africa
Featured Image: Boabab tree in Botswana via Pixabay