Ancient Migration: A Journey Through a Colder Climate to the Americas
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The main theme of Human Stories revolves around the global migration of our species. From their origins in Africa, our ancestors traveled to Europe, Asia, Australia, and eventually reached the Americas. South America was the last continent they settled, with Antarctica being the notable exception.
This chapter of our history remains somewhat enigmatic. While ample research has focused on human migration into Europe, Asia, and North America, far less attention has been directed toward their entrance into South America.
Reflecting on this, I discovered that my previous detailed analysis of South America appeared in June 2023.
However, this narrative is beginning to evolve. On May 15th, a significant genetic study was published in Science, unveiling crucial insights into early inhabitants of South America. This extensive research indicates a diverse population across different regions, revealing a fourfold division of early groups. These findings align with newer stories of remarkable journeys and the extraordinary risks taken in the quest for new lands.
A Complex Journey
If you consider how Homo sapiens evolved in Africa, the task of reaching South America becomes apparent. The vast Atlantic Ocean acted as a major barrier between continents, complicating the path for humans.
This migration was not premeditated; at that time, people had no knowledge of South America’s existence. They journeyed as far as they could see, moving from Africa to Southwest Asia, and eventually to various parts of Eurasia. Some even ventured as far as the easternmost regions of Asia, now known as Chukotka in the Russian Far East.
From there, it was a relatively short journey to present-day Alaska in northwest North America. Evidence suggests humans arrived at least 16,000 years ago. Today, the Bering Strait—a mere 82 kilometers across—seems a significant barrier. However, thousands of years ago, colder climates meant lower sea levels, creating land connections between Asia and North America, notably Beringia. People may have unknowingly traversed what would become a monumental migration.
Supporting this theory, a study released in May highlighted that horses traveled regularly between North America and Asia via Beringia between 50,000 and 13,000 years ago, suggesting humans could have followed suit.
Additionally, recent findings indicate that the bacteria responsible for leprosy originated in America, with studies revealing Mycobacterium repromatosis has been present in the Americas for approximately 10,000 years.
For unknown reasons, the earliest groups of Americans moved southward. Some utilized boats along the Pacific coast, while others ventured inland, ultimately reaching the southernmost tip of South America.
The archaeological record of these groups is rich. A study published in February analyzed a large collection of artifacts dating back 10,000 to 11,000 years in the Takualembo region of Uruguay.
Who were these early South Americans? That’s where new genetic research comes into play.
Continuing the Journey
Led by Hie Lim Kim from Nanyang Technological University in Singapore, researchers compiled genomic data from 1,537 individuals across 139 ethnic groups. This included individuals with ties to northern Eurasian populations, as well as groups from the Americas, particularly South America.
“Our study showcases the history of this vast migration,” Kim states.
Between 13,900 and 10,000 years ago, the initial settlers of South America divided into four genetically distinct groups. Signs of these genetic patterns persist in modern South Americans.
Kim highlights the challenge of providing a comprehensive account of these findings. While the study identifies genetic differences among populations, they don’t necessarily align with cultural traits. “We didn’t categorize them by culture or language,” she explains, “but solely based on ancestry.”
With this caveat, Kim’s team identified four groups: Amazonians, Andeans, Chaco Amerindians, and Patagonians, named for regions where contemporary genetic signals are strongest. For instance, Amazon ancestry aligns with current populations in the Amazon rainforest, Andean ancestry with those in the Andes mountains, and Patagonian ancestry with people from southern Argentina. The Chaco Amerindian lineage is traced to the Dry Chaco, spanning parts of Argentina, Bolivia, and Paraguay. “They are predominantly hunter-gatherers in arid regions,” says Kim.
Once these groups branched out, signs of significant gene flow between them became scarce. “They have never intermingled again,” says Kim, suggesting geographic barriers like the Andes may have fostered this separation.
However, Kim asserts this is likely not the entire narrative, as additional groups may exist. “Our sample from Brazil is limited,” she notes. “Many ethnic groups in the Amazon remain unexplored.”
Recent research further enriches this narrative. In March, archaeological evidence pointed to a location known as Southern Corn, situated near the 22nd parallel south encompassing northern Argentina, Paraguay, Chile, and Uruguay.
Another study from March detailed the journey of the Guarani, who traversed over 2,500 kilometers across South America, ultimately reaching the mouth of the Rio de la Plata estuary, now Buenos Aires and Montevideo.
Late May research uncovered the risks associated with migration; ancient Colombian DNA indicated an unknown hunter-gatherer population that inhabited the Bogotá Altiplano around 6,000 years ago. By 2,000 years ago, they were replaced by Central American populations, leaving no trace in today’s genetic pool.
South America is vast, and we have merely scratched the surface of its complex history. Numerous untold stories lie waiting to be uncovered.
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Source: www.newscientist.com
