Mar 12, 2020
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A massive lake glistens beneath the sun, cutting a clear expanse across an otherwise lush wetland. Here, a new species, Homo sapiens, has gathered, with these modern humans having evolved from their Neanderthal ancestors. Humankind started here some 200,000 years ago, in fact, and scientists have just now pinpointed the surprising place where it all began according to petdetective.com.
The experts helming the study used scientific data to pinpoint this verdant locale. In particular, they had to rely on mitochondrial DNA, which they gathered from the cells of 1,217 samples. This battery-shaped genetic material passes from mothers to their children, so the researchers had to find a population with a maternal line that stretched far into the past.
With the right DNA information gathered and analyzed, the research team then highlighted a general area. After that came further archaeological and geological research, which helped them to find something spectacular: evidence of a massive, ancient lake that broke down into wetlands. Its lush greenery was the backdrop for the first humans to walk the Earth, and its modern-day location may just surprise you.
Experts have long believed that humankind traced all the way back to the African continent. However, mapping evolutions and migrations has been a difficult task, to say the least. It was about seven million years ago when human beings began to evolve, splitting off from primates such as the chimpanzee and the bonobo.
As it stands, it’s virtually impossible to find every link between humans and primates, since scientists simply don’t have enough fossil records to achieve this. Indeed, entire species may have come and gone without leaving a trace for experts to uncover today; instead, they only have bits and pieces to work with.
However, the picture of humankind’s ancestral roots becomes clearer as scientists move nearer to the present day. They know, for example, that Neanderthals roamed Europe and even trekked into Siberia and Central Asia – although not as far as Africa. But while this population may have paved the way for modern humans, they did not actually originate the species.
Instead, it would be the evolution of Homo heidelbergensis and Homo erectus that gave way to Homo sapiens. And these new humans presented a variety of slight differences that separated them from the likes of the Neanderthal population who roamed the continent above them. For one, Homo sapiens took on a more slender build than the stockier Neanderthals up north.
In addition, modern humans mastered the art of making tools in a way that Neanderthals hadn’t. The African contingent styled their weapons to have sleek, elongated blades. They also fashioned them into more sophisticated throwing spears, which made their hunting more effective; the Neanderthals, by contrast, wielded clunkier weapons that had been chiseled from large stones.
However, the fact that both the Homo sapien and Neanderthal populations had similar lifestyles did confound experts. As a result, then, they formulated two main theories about how and where humankind developed. Some believed in what’s called the multi-regional hypothesis, which states that human ancestors spread across the globe – thus allowing modern humans to evolve in a handful of different places worldwide.
Then there was a single-origin concept known as the out-of-Africa theory. As the name suggests, this idea purports that modern humans grew and evolved on the continent for millennia before migrating to other areas of the Earth. And by the 1980s, scientists would have what appeared to be a clear confirmation of the out-of-Africa concept.
DNA testing completely revolutionized science in a number of ways. In terms of humankind’s ancestral roots, scientists could analyze the genetic information of modern populations. From there, they traced subjects’ lineages back into the distant past, and these mappings always led researchers to one place of origin: Africa.
Even in these original studies, experts relied on mitochondrial DNA when tracing their subjects’ ancestral lineage. They do so because this part of the genetic code comes from a person’s mother; in addition, this section of DNA will present mutations more readily than others. As such, it’s easy to follow how a mutation has passed from mother to child for generations.
In fact, in tracing this mitochondrial DNA back all the way to the cradle of civilization, experts realized that one woman’s genetic code has been carried through to everyone on Earth today. She’s known to scientists as “Eve,” although she’s not the same as the biblical figure – and is not considered as the first ever human woman on Earth.
Rather, Eve lived when the entire human population was a mere 10,000 people. As such, she was neither the only, nor the oldest of our ancient predecessors. She just happened to have an unbroken line of daughters who passed her mitochondrial DNA onto their baby girls and down through the ages right through to the present day.
In short, Eve is regarded as humankind’s “most recent common ancestor,” according to Smithsonian magazine. A 2008 DNA analysis confirmed, too, that she is the only woman of that time to have an unbroken lineage of daughters and therefore retraced Eve’s origins. And scientists concluded that she had originated in Africa – more specifically, the eastern area of the continent.
Eve’s DNA therefore seemed to reveal the start of humankind’s story. However, experts had lots of other questions. If the species originated in Africa, how did they spread out to other continents? And why were such a disproportionate number of fossils from Europe? To answer these queries, then, the researchers combined the same DNA evidence with archaeological finds.
All of this information pointed to major migrations that started between 60,000 and 80,000 years ago. At that time, modern humans left their African origins for Asia. By about 45,000 years ago, they had moved into Australia, Indonesia and Papua New Guinea, too. Then, 5,000 years after that, bands would leave Africa for Europe.
Humans who journeyed from Africa to Europe likely took one of two pathways to get north. Some would have traced the Mediterranean coast to get onto the continent, while others passed through Turkey and along the Danube. Their insurgence pushed Neanderthals into a few mountainous areas until the species disappeared about 25,000 years ago.
The final step in humankind’s journey would bring them to the Americas. This happened about 15,000 years ago and began in Asia. From there, Homo sapiens traveled across the Pacific to reach North America first. Once on land, some of them continued to wander until they reached South America and settled there, too.
And it’s hard to believe that all of this information comes with little fossil evidence of the first humans who started it all. This is especially surprising considering the changes that have occurred on the African continent, where humankind is said to have originated. Today, the dry landscape easily erodes and reveals the bones of those who died there centuries ago.
Even so, archaeologists have had little luck in uncovering the remains of the earliest Homo sapiens – whether they dig in Africa or in Europe. As such, they believe that the first humans maybe did not bury their dead like the Neanderthals, choosing instead to cremate them or leave them to decompose out in the open.
Yet despite this lack of skeletal remains, modern science and technology has allowed researchers to pinpoint human origins even more. A 2019 study helmed by geneticist Vanessa Hayes of the Garvan Institute of Medical Research in Sydney relied once again on mitochondrial DNA for answers.
Hayes and her team gathered 1,217 mitochondrial DNA samples from people who currently live in southern Africa. Some of the test subjects even came from the Khosian population – an indigenous group who speak with clicking consonants and have long foraged for their sustenance.
From those samples, Hayes and the team traced what’s known as the L0 lineage in the subjects’ mitochondrial DNA. The L0 lineage traces all the way back to Eve, humankind’s common ancestor. Over time, her original DNA split into five main branches as people left Africa and diversified.
The L0 line, as it’s called, also has its own deviations. For instance, it branched about 130,000 years ago, when some of the human population moved from their original homes as heavy rains transformed dry lands into vegetation that could support human life. While some people followed this greenery to the southwest, though, others moved northeast to become farmers and foragers.
But the L0 mitochondrial DNA started somewhere, and Hayes and her team were able to pinpoint precisely where. Generally, they found that L0 and all of its sub-branches once again placed the earliest humans in Africa. Their territory stretched from Namibia, into Botswana and then on to Zimbabwe.
Then Hayes and the research team added geological, fossil and archaeological evidence into their findings. And while some of the area of interest may seem uninhabitable in the modern era, the information gleaned about this potential point of human origin showed that it used to look very different.
The massive Lake Makgadikgadi – roughly the size of New Zealand – once covered a huge swathe of modern-day Botswana. Eventually, it started to transform from lake into wetland about 200,000 years ago. And according to Hayes and her team, this marshy expanse was the cradle of modern humankind.
Looking at the region today, though, it’s hard to believe that the origins of human life on Earth could have grown from this arid area. The one-time wetland sits south of the Zambezi River, but it’s nothing like it was in its water-logged past. Instead, it has dried up into sprawling salt pans, with white expanses of the mineral glistening in the sun.
According to Hayes, however, the area looked a lot different 200,000 years ago. In place of the unforgiving salt pans was a resource-laden wetland. As she told The Guardian in 2019, “It would have been very lush, and it would have provided a suitable habitat for modern humans and wildlife to have lived.”
At the time, the Botswana-based wetland would have served as an oasis for the arid area surrounding it. As such, humankind may have started there 200,000 years ago and remained in the area for 70,000 more years. A shift in climate eventually pushed the founding humans from the wetlands, however.
As the Earth’s orbit and tilt shifted, it brought rains to new stretches of African land. Precipitation then encouraged plant growth, which sprung up in lengthy, lush corridors. These green pathways gave humans a reason to branch out of their wetland home and into new territories – a precursor to their great global migration, which began about 60,000 to 80,000 years ago.
ssentially, Hayes and her team reiterated the long-held origin of humankind’s roots, but they pinpointed the spot as a wetland in Botswana. She said, “We have known for a long time that modern humans originated in Africa and roughly 200,000 years ago, but what we hadn’t known until this study was where exactly.”
Not all experts felt convinced by Hayes’ research, however. Chris Stringer, an expert in human origins at London’s Natural History Museum, admitted that modern DNA samples might not be entirely representative of the past. He explained, “I’m definitely cautious about using modern genetic distributions to infer exactly where ancestral populations were living 200,000 years ago – particularly in a continent as large and complex as Africa.”
Stringer also felt that Hayes and her team had been overly reliant on the mitochondrial DNA – and L0 lineage – as the main factor in their research. He cautioned, “Like so many studies that concentrate on one small bit of the genome, or one region, or one stone tool industry, or one ‘critical’ fossil, it cannot capture the full complexity of our mosaic origins once other data [is] considered.”
In addition, other studies have traced humankind’s ancestors back to other pockets of the African continent. As one example, Stringer highlighted a study focused on the Y chromosomes that only men inherit, and this research suggested that migration has commenced from west Africa – quite a distance from landlocked Botswana in the south.
Additionally, another study found that those who left Africa for other lands carried genomes that traced back to the continent’s eastern areas. Stringer concluded, “These and many other data suggest that we are an amalgam of ancestry from different regions of Africa with, of course, the addition of interbreeding from other human groups outside the continent.”
Ultimately, Stringer called Hayes’ findings an “over-reach.’ He told BBC News, “You can’t use modern mitochondrial distributions on their own to reconstruct a single location for modern human origins. I think it’s over-reaching the data because you’re only looking at one tiny part of the genome, so it cannot give you the whole story of our origins.”
Furthermore, some scientists still believe that humankind came from more than one single place. University of Cape Town archaeologist Rebecca Ackermann told The Guardian that our roots could be in Africa – and beyond. She noted, “Drawing sweeping conclusions about places of origin from analyses of this tiny part of the modern genome is deeply problematic and outdated.”
Nevertheless, Hayes’ study did pinpoint one potential origin for humankind, and many experts have long believed that the species did, indeed, evolve in Africa. And even with modern science and DNA testing, it still may prove an impossible question to answer definitively. For now, though, we can consider life as it may have been 200,000 years ago, with the first humans finding their way in a Botswana wetland.
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