Ancient Cave Skeleton Sheds Light on Early American Ancestry

By Gemma Tarlach | May 15, 2014 1:00 pm
divers hold early american skull

Divers transport the Hoyo Negro skull to an underwater turntable so that it can be photographed in order to create a 3-D model. The project was supported by the National Geographic Society. Photo Credit: Paul Nicklen/National Geographic.

An ancient human skeleton discovered in an underwater Mexican cave has answered a crucial question about early Americans: How they came to look so different from their Siberian ancestors.

Genetic studies have pointed to a Siberian ancestry for modern Native Americans. Most researchers believe the first Americans (Paleoamericans) migrated from northeast Asia via Beringia, the now-submerged land bridge between present-day Siberia and Alaska, some 18,000-26,000 years ago. But the facial features of the oldest American skeletons don’t look much like those of modern Native Americans. This has inspired a number of controversial counter-theories claiming the Americas were first settled by people from elsewhere in Eurasia.

Now, the near-complete skeleton of a teenaged girl, believed to be 12,000-13,000 years old, is helping settle the debate. Her skull, with its narrow face, prominent forehead and wide-set eyes, is similar to that of other skulls considered to be Paleoamerican — but she shares a genetic signature with modern Native Americans.

Facial Divide

The skeleton was found in the Hoyo Negro (“Black Hole”) cavern beneath Mexico’s Yucatan Peninsula. Called “Naia,” after the Greek word for “water nymph,” she is the first specimen with Paleoamerican craniofacial features to have its DNA successfully sequenced. Researchers announced today that Naia’s mitochondrial DNA (mtDNA) shares a genetic lineage with Native Americans. The lineage, known as haplogroup D1, derived from the northwest Asian haplogroup D and is unique to the Americas. Just as importantly, researchers found no genetic evidence suggesting Naia had ancestors from elsewhere.

The Hoyo Negro find proves at least some ancestors of modern Native Americans had Paleoamerican features, effectively shutting down the theories that contended it was not possible. Speaking to reporters about the Hoyo Negro results on Wednesday, researchers involved with the study suggested that the craniofacial features specific to modern Native Americans could easily have evolved in a few thousand years, well after the first Americans were established here, and pointed to numerous known examples of similarly fast adaptations in humans to environmental factors such as cold or altitude.

Cave Treasures

The Hoyo Negro skeleton, the most complete Paleoamerican remains known, was found by three divers exploring the cave in 2007. The divers also found the remains of at least 26 animals, including sabertooth cats (Smilodon fatalis) and the elephant-like gomphothere (Cuvieronius cf. tropicus), both now extinct.

At the time Naia lived, the enormous cavern — about 170 feet deep and 200 feet in diameter — was about five miles inland from the Caribbean and not submerged, though small amounts of water occasionally collected on its floor. Beginning about 10,000 years ago, at the end of the last Ice Age, as glaciers melted and the sea levels rose, Hoyo Negro was gradually inundated. By 8,000 years ago, the cave and its access tunnel were completely underwater.

Hoyo Negro currently can only be reached by highly skilled divers via a 3,000-foot-long tunnel full of hazards. For this reason, and because researchers were committed to preserving the cave’s scientific integrity, progress on analyzing the remains has been painstakingly slow. Even confidently dating the skeleton was challenging.

Dating Naia

Because the underwater environment was poor for preserving bone collagen, researchers were unsuccessful in their attempts to date the bones of both human and animal remains using radiocarbon dating. Instead, the team relied on three separate methods. First, they aggregated data about sea levels in the area over the past several thousand years and determined when Hoyo Negro filled with water, concluding that the bones found there must have been deposited before then. The team also took note of the approximate extinction dates of the animal species found in the same area as Naia.

Finally, researchers conducted isotopic analysis of crystals growing on both human and animal bones found in the caves. They were able to determine when the crystals began growing and whether they were exposed to air or were underwater, allowing them to narrow down the age of the skeleton from 12,000-13,000 years old.

Other researchers on the international team sequenced the mtDNA extracted from one of the skeleton’s teeth; two additional labs independently performed the same sequencing to verify the results.

Researchers provided a video about the finds at Hoyo Negro and their significance.

The findings complement the recent whole-genome sequencing of an early American, the infant boy Anzick-1, who lived about 12,600 years ago in what is now Montana. Because Anzick-1’s remains did not include his skull and jaw, however, researchers had been unable to determine whether his craniofacial features were typically Paleoamerican or more similar to that of modern Native Americans.

Researchers who worked on the Hoyo Negro study, published today in Science, said that a facial reconstruction of Naia would be released in June and that an attempt to extract and sequence nuclear DNA from the remains — which would provide additional details about her ancestry and relation to modern Native Americans — is already underway.

CATEGORIZED UNDER: Living World, top posts
MORE ABOUT: paleontology
  • Mikels Skele

    Well, this certainly re-invigorates the Kennewick Man controversy!

    • Jack Nextdoor

      Not really, although it does further explain the Kennewick Man.

      • Reddy

        In what way is that not a re-invigoration?

        • Jack Nextdoor

          You specified controversy. I don’t see that this will reinvigorate a controversy, but it does add to the science.

    • Reddy

      I don’t think it does, Kennewick Man set a helpful precedent for science. Religious views should never hamper scientific investigation, ever. Remains should be returned to rightful owners if traceable (and they want them) but only after they and their context have been understood. It looks like this precedent is being upheld as there’s no mention of controversy here.

  • Rebecca de Haan

    well that proves the mormons wrong with a vengeance! :-)

    • Brent Lee Cole

      How so?

      • derp

        lol. mormons questioning.

    • Christopher Nicholson

      No it doesn’t. The Book of Mormon text doesn’t claim that its peoples were the only ancestors of Native Americans, or that they inhabited the entire hemisphere.

      • Rebecca de Haan

        Yes it does. Or at least it did. Before the church changed it recently…and how about god telling the people in the BOM that he had saved the land especially for them, that no other peoples had ever set foot on it etc…don’t take me for a fool pleae. I was a member of that church for 20 years. I probably know more about it than the average member today.

      • Tania Q

        Taken with flint head and all the other evidence (overwhelming really) the B of M story remains entirely unsupported and most unlikely. If Joseph Smith made up the Pearl of Great Price, which cannot be disputed, then he was more than capable of also fabricating other stories.

      • http://blogs.discovermagazine.com David Benstog

        Since scientists were able to find DNA evidence from a 12,000 old skeleton showing her likely origin, they should have no trouble finding genetic evidence from the millions of Native Americans alive today to support the BOM claims of the “lost tribes of Israel.” Since they haven’t found any, it puts the BOM on a long list of other fraudulent works of fiction. Joseph Smith was nothing more than a clever con man hoping to use religious claims to gain a following the hoped for perks that would come with it.

  • Rservefiftytwo

    OK wow man thats like some pretty cool stuff.
    Anon-VPN dot COm

  • JIMA

    Mermaid skull fo sho

  • somchai672000

    SEARCH : Ancient America; Egyptians in America

  • FartNoMore

    Glenn Danzig wants that skull.

  • http://www.arianabrowning.com/ Ariana Browning

    Interesting and timely. My mom was shocked by research my Uncle (her brother) is doing to trace our roots. She doubted he was correct about Siberia ancestry. He’ll enjoy finding this information out.

  • http://blogs.discovermagazine.com Kim Jobe

    This is fascinating, but a single piece of evidence like this isn’t enough to definitively prove or disprove any population theory. We do our ancestors a disservice if we believe they could ONLY have traveled via the land bridge. As the Polynesians showed, determined people in small boats can make amazing voyages! Why are we only willing to entertain the theory du jour? Surely science is big enough to allow multiple theories. Whether or not they can be “proved” remains to be seen.

    • http://blogs.discovermagazine.com David Benstog

      I’m all for legitimate scientific theories based on sound research. Not so much for religious claims that anyone can make, with no evidence to support them. Joseph Smith and the BOM fit in this category.

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