Scientists Discovered Two 11,500-Year-Old Skeletons And Unlocked Ancient Secrets About DNA
Human DNA was indeed first discovered in the 1860s, marking a significant milestone in our understanding of human life. Since then, scientists have made numerous discoveries that shed light on early human history. In 2018, a notable breakthrough occurred when a team of scientists unearthed the skeletons of two Native American infants.
This discovery yielded unexpected information and valuable insights that extended beyond their initial expectations. Read on to learn more!
The Discovery Of The Infant Skeletons
In 2018, archaeologists unearthed the skeletons of two Native American infants. Remarkably, these skeletons were approximately 11,500 years old and belonged to individuals from the same family.
The exceptional preservation of these remains provided scientists with valuable insights into early human history, offering crucial information about the earliest human inhabitants of North America and their migratory patterns.
It All Started In Upward Sun River, Alaska
In the early 2000s, Professor Ben Potter, an anthropology expert, embarked on an excavation project in Upward Sun River, Alaska. This remote forested area, located approximately 50 miles from Fairbanks, posed challenges of accessibility and could only be reached by helicopter.
Potter's decision to excavate in this region was based on compelling reasons. The geological history suggests that the area was once connected to Europe and Africa, making it an intriguing site for studying ancient human migrations and the peopling of the Americas.
What Is Beringia?
When the supercontinent Pangea started to break apart, certain land bridges remained intact, providing connections between different continents. Africa is widely recognized as the birthplace of the earliest known humans, but human migration subsequently took place across the globe.
Beringia, the land bridge spanning from Siberia to Alaska, is of particular significance in understanding the peopling of North America. Many archaeologists hypothesize that the first humans to populate North America crossed this bridge approximately 34,000 years ago. However, it is important to note that this theory is still subject to ongoing research and investigation.
The Beringian Standstill Hypothesis
Archaeologists suggest that early humans crossed Beringia, but their identity remains unknown. The Beringian standstill hypothesis offers insight: "Ancient Beringians" likely resided in isolation on Beringia due to icy conditions. If accurate, they could be the exclusive forebears of Native Americans, as proposed by archaeologist Jennifer Raff.
Potter Collaborated With Local Native Americans
The title "Upward Sun River" originates from the Athabascan Xaasaa Na' language, spoken by present-day Native Americans in Alaska. Potter's excavation efforts were conducted in collaboration with the Native community. Recognizing the significance of his work, the Natives graciously extended their assistance to him.
Potter Discovered Something In 2010
In 2010, Potter and a team of University of Alaska researchers conducted a search at Upward Sun River, where they made a remarkable find: the cremated remains of a three-year-old child. This discovery, dating back 11,500 years, was highly unusual. Regrettably, the skeleton was not well-preserved, making it impossible to extract DNA or determine the child's gender.
Despite The Letdown, Potter Didn't Give Up
Despite their limited success, Potter and his team did not give up. They continued to excavate in that area for eight more years.
Then, Potter and his colleagues, José Víctor Moreno Mayar and Lasse Vinner, found their big break. They unearthed a burial site in an area of Alaska that was around 15,000 years old.
Finally, They Found The Skeletons Of Two Infants
There, Potter and his team discovered two infant skeletons. One seemed to be a stillborn; the other was between six and 12 weeks old.
Like the three-year-old, the two seemed to have been cremated, as their remains rested on a fire pit. However, these remains were much more preserved and easier to identify.
The Burial Ground Was Well-Preserved
The two infants were buried beneath multiple items and covered in red ochre. This ochre, which was likely part of the funeral process, further preserved the skeletons.
The babies were also buried beneath a mixture of sand and soil. This high-acidity mixture is ideal for conservation. Clearly, the people who buried them loved them dearly.
Who Were The Two Girls?
DNA testing revealed that both infants were girls and that they were both related, possibly first cousins. The stillborn died at 30 weeks old, having never gotten the chance to live.
The local Native community named the girls Xach'itee’aanenh T’eede Gaay" (Sunrise Girl-Child) and "Yełkaanenh T’eede Gaay” (Dawn Twilight Girl-Child).
Other Items Were In The Grave, Too
This gravesite was clearly important to the mourners. Archaeologists discovered many other items in the grave, such as antler and spear points.
Both girls were buried together in a joint funeral. However, Sunrise Girl (the six-week-old infant) seemed to be better preserved and served as the basis for most of the DNA results.
What, Exactly, Were The Researchers Studying?
To examine the DNA, geneticists had to dig into the mitochondria. Science students remember the mitochondria as "the powerhouse of the cell" because, without it, cells die.
Every cell in the body contains DNA, and the mitochondria is responsible for running cells. Hence, the scientists need undamaged cells to examine--which is easier said than done.
Here's Why They Couldn't Study The Three-Year-Old
Old bones are not guaranteed to have live cells. If scientists want to examine DNA, they need a thick enough bone that is decently preserved.
Usually, researchers test the petrous bone, which is at the base of the skull. Because the three-year-old's bones were too damaged, researchers could not test the DNA. But with the two infants, they could.
What Came From The DNA Tests?
The first round of DNA tests, performed at the University of Alaska, revealed the ethnicity of Sunrise Girl. According to the results, she was closely related to Native Americans, but in a distinct way.
Scientists believe that her DNA is far older than any previously tested remains. In other words, she is a previously unknown genetic population of Native Americans.
They Revealed A New Ancient Human
This previously-unknown DNA, which scientists dubbed USR1, dates back at least 20,000 years and possibly as far back as 34,000. Eske Willerslev, the study's co-author and professor at the University of Copenhagen, says that they are the oldest known Native Americans to date.
"It changes our understanding of the timing of events that formed the genetics of Native Americans," Willerslev told CNN Health.
They Might Be Ancient Beringians
Sunrise Girl's DNA lends credence to the Beringian standstill hypothesis. Scientists believe that she might be an Ancient Beringian that experts had only theorized about beforehand.
"We think the explanation for this pattern, the one that requires the least movement, was that Native Americans were somewhere in Beringia 20,000 years ago," explained Victor Moreno Mayar, another author of the study.
But The Two Girls Had Different DNA
The first DNA analysis was done on the six-week-old's skull. Geneticists expected the second infant to have similar DNA. But surprisingly, she didn't.
Dawn Twilight Girl the stillborn, was examined at the University of Copenhagen, Denmark. She had an entirely different maternal lineage compared to her first cousin, and the lineages were not related.
Researchers Say There Were Two Branches Of Native Americans
Geneticists have separated Native Americans into two branches: Northern and Southern. The Northern group came from East Asia and likely inhabited North America, including Alaska and Canada.
At some point, the group split and the Southern Native Americans migrated to South America. They all descended from the Ancient Beringians, but the separation created variations in their DNA.
The Two Infants Had Different Ethnicities
In simpler terms, DNA tests indication that both girls belonged to two separate groups. Sunrise Girl belonged to the Ancient Beringias, while Dawn Twilight Girl came from another ethnicity, one more closely related to the Northern Native Americans.
This begets the question: how did these two groups of people end up in the same place at the same time?
However, Sunrise Girl Belonged To A Mysterious Third Group
Surprisingly, Sunrise Girl did not belong to either of these groups. This means that the Ancient Beringians split into at least three groups, if not more.
With demographic modeling, scientists estimated that Native Americans left East Asia 36,000 years ago. By 20,000 years ago, this group split. But if they split, why were these two infants buried together?
All Groups Split Off From One
In the study, archaeologists hypothesized that the two groups stuck together at least once--hence why the girls were related. They proposed two possibilities for this.
The Beringians might have split before crossing the bridge, only to reunite later. Or, the Beringians might have separated after crossing. Potter prefers the latter theory.
Perhaps They Split Before Beringia
Potter has a theory for how these two groups came together. During an interview with The Atlantic, he suggested that both groups independently crossed Beringia. Perhaps they traveled on different paths at separate times.
Usually, this theory would seem a bit far-fetched. But there is some evidence to back it up.
Support For Potter's Theory
In 2017, archaeologists examined the Bluefish Caves in Canada's Yukon Territory. According to a study on these caves, scientists found evidence of human-cut markings that were 24,000 years old.
If this is accurate, as Raff believes it is, then humans had crossed Beringia at least 24,000 years ago. That was over a decade before the two girls were born.
Some Experts Argued Against Potter's Conclusions
The main argument against this finding is just that: It's a single finding. Dennis O'Rourke, a geneticist and archaeologist, says that the one sample is not enough evidence to study the entire human population.
"We could know something about the extent of diversity in this early Beringian population with greater certainty if we had multiple genomes," O'Rourke told The Smithsonian Magazine.
However, These Findings Are Exceptionally Rare
But finding more than one sample is easier said than done. "It's hard to impress upon you how rare they are," Potter told The Atlantic.
According to co-researcher Willerslev, before this finding, scientists only had modern-day Alaskans and Siberians to study this genome. Without more samples, nobody will know where the Beringians came from.
Plus, Upward River Is Too Young For Ancient Humans
Despite the age of Upward River's burial grounds, archaeologist Brian T. Wygal claims that it is too young to understand early humans.
"The earliest proven trace of human activity in eastern Beringia dates to around 14.1-thousand-years-ago," Wygal explained, "making the Upward Sun River site nearly 3,000 years too young to be representative of the initial human colonization of the New World."
What Happened To The Beringians?
After Potter's study released--which is in the scientific journal Nature--many have asked what happened to the Beringians. "We don't know," Potter told CNN.
Again, this question needs more evidence to answer. However, Potter plans to take DNA samples from the neighboring residents. Since scientists know what Beringian DNA looks like, they can determine if the gene still exists in Natives
What Were The Beringians Like?
Research has revealed a snapshot of the Beringian's life. According to Potter, they were expert hunters, eating bison, elk, rabbits, squirrels, and birds.
They likely hunted through organized parties. Potter also found evidence of "salmon exploitation" dating back 6,000 years, meaning that the Beringians likely fished and traded as well.
They Might Have Evolved Into The Modern Native Americans
Potter suggested that the Beringian gene might have assimilated into the indigenous peoples of Alaska. This is a natural consequence of evolution.
"It is possible that incoming Athabaskan ancestors, who are widespread throughout the region today, replaced or absorbed the Ancient Beringians inhabiting that area," Potter claimed. If that is true, many people might have Beringian blood and not even know it.
