Scientists have confronted a mystery of how the Americas were first settled. The first people who walked across the Bering Strait from Asia around 20,000 years ago are the ancestors of Native Americans, yet modern people look rather different from those first immigrants. A theory that explains this difference is that other migrations took place afterward, and the different waves of immigrants interbred. DNA evidence from a skeleton found in an underwater cave sheds some light on the question.
Between 12,000 and 13,000 years ago, a 15-year-old girl wandered into a cave now called Hoyo Negro (“black hole”) on the Yucatan Peninsula in Mexico and died. Then the Ice Age glaciers melted and the cave was filled with water. In 2007, divers discovered her skeleton and the DNA of the girl they call Naia has since been sequenced.
Tests on mitochondrial DNA taken from Naia show that she had a genetic marker common today across the Americas, one that scientists say evolved in a prehistoric population that had been isolated for thousands of years in Beringia, the land mass between Alaska and Siberia that formed a bridge between the continents during the Ice Ages.
Thus, according to the report, the Native Americans and the Paleoamericans are the same people, descended from the same Beringia population. They just look different because of recent evolution.