DNA LINKS PALAEOAMERICANS AND MODERN NATIVE AMERICANS

The skeletal remains of a teenage female from the late Pleistocene or last ice age found in an underwater cave in Mexico have major implications for our understanding of the origins of the Western Hemisphere’s first people and their relationship to contemporary Native Americans.

In a paper released in the journal Science, an international team of researchers and cave divers present the results of an expedition that discovered a near-complete early American human skeleton with an intact cranium and preserved DNA. The remains were found surrounded by a variety of extinct animals more than 40 metres (130 feet) below sea level in Hoyo Negro, a deep pit within the Sac Actun cave system on Mexico’s Yucatán Peninsula. The Hoyo Negro project was led by the Mexican government’s National Institute of Anthropology and History (INAH) and supported by the National Geographic Society.

Significant findings

  • This is the first time researchers have been able to match a skeleton with an early American (or Palaeoamerican) skull and facial characteristics with DNA linked to the hunter-gatherers who moved onto the Bering Land Bridge from northeast Asia (Beringia) between 26,000 and 18,000 years ago, spreading southward into North America sometime after 17,000 years ago.
  • Based on a combination of direct radiocarbon dating and indirect dating by the uranium-thorium method, it is one of the oldest skeletons discovered in the New World.
  • It is clearly the most complete skeleton older than 12,000 years as it includes all of the major bones of the body and an intact cranium and set of teeth.

Differences the result of in situ evolution

According to the paper’s lead author, James Chatters of Applied Palaeoscience, “This expedition produced some of the most compelling evidence to date of a link between Palaeoamericans, the first people to inhabit the Americas after the most recent ice age, and modern Native Americans. What this suggests is that the differences between the two are the result of in situ evolution rather than separate migrations from distinct Old World homelands.”

The field research team endured extremely challenging conditions to access the skeleton’s remote underwater location at the bottom of Hoyo Negro, deep beneath the jungles of the eastern Yucatán Peninsula. The multidisciplinary team, composed of professional divers, archaeologists and palaeontologists, extensively documented the bones in situ.