May 21, 2014

The discovery of a nearly complete skeleton of a young girl who died nearly 13,000 years ago in what is now Mexico is providing evidence that anthropologists claim will end a decades-old debate over the origins of Native Americans. A diverse team of scientists led by anthropologist James Chatters published a description of the skeleton, which included preserved DNA, in the May 16 issue of Science. The discovery may finally end an often heated, decades-long debate among anthropologists over why Native Americans do not resemble Paleo-Indians, the first people to migrate to the Americas.

Underwater archaeologists discovered the skeleton of the young girl, perhaps only 13 years old when she died, with bones of extinct Ice Age animals. The skeleton was found while the scientists were exploring a submerged cave, called Hoyo Negro (black hole), in the Caribbean Sea, off the Yucatan Peninsula of Mexico. Scientists named her Naia, after a water nymph (maiden) in Greek mythology. The scientists speculate that Naia may have fallen into an underground cave while searching for water and died. As sea levels rose by the end of the Ice Age, the cave was submerged, creating ideal conditions to preserve Naia’s bones along with the bones of other animals that shared her fate.

Genetic studies of Native Americans indicate that their ancestors migrated into the Americas from Asia more than 12,000 years ago. The oldest known Paleo-Indian culture is the Clovis culture, identified by distinctive stone spearheads, called Clovis points. Archaeologists have discovered a only handful of Paleo-Indian skeletons, including Kennewick Man, found in Washington in 1996. However, these ancient skeletons do not physically resemble today’s Native Americans. Paleo-Indian skulls are longer and narrower, with forward projecting faces. These features are most similar to those of native people of Australia and the Ainu, an isolated native population of Japan.

The prehistoric Clovis people made distinctive stone spearheads, called Clovis points. The Clovis are the earliest known Paleo-Indian culture of the Americas (AP Photo).

Some scientists theorize that the Paleo-Indians are not the ancestors of modern Native Americans. They suggest that Native American ancestors arrived from Asia in a later migration and, over time, replaced the Paleo-Indians. Other scientists disagree. They argue that the physical features of Paleo-Indians evolved over thousands of years, giving rise to modern Native Americans.

Now, Naia may end the debate. Naia’s skull has all of the physical characteristics that confirm her identity as Paleo-Indian. However, DNA isolated from her skeleton allowed the scientists to directly link her with living Native Americans. Naia’s mitochondrial DNA—genetic material passed down from mother to child through the egg—included specific sequences of DNA that linked her with ancient populations of northeastern Asia as well as Native American peoples alive today. Similar DNA sequences were recently reported from the only known skeleton of a Paleo-Indian infant, discovered in 2001 at Anzick, a site in Montana. The DNA evidence points to Paleo-Indians as the direct ancestors of modern Native Americans. Naia indicates that the physical difference between her people and modern Native Americans results from evolutionary changes occurring over time rather than separate ancestry.

Additional World Book articles:

• Prehistoric people
• Fascinating Facts About Fossil Feces (a Special Report)
• The First Americans (a Special Report)