A horrible day for a teenage girl perhaps 13,000 years ago -
death in a Mexican cave - has turned into a wonderful day for
scientists who have managed to coax important secrets out of
the oldest genetically intact human skeleton in the New
Scientists say genetic tests on her superbly preserved
remains found by cave divers have answered questions about
the origins of the Western Hemisphere's first people and
their relationship to today's Native American populations.
These findings determined that the Ice Age humans who first
crossed into the Americas over a land bridge that formerly
linked Siberia to Alaska did in fact give rise to modern
Native American populations rather than hypothesized later
entrants into the hemisphere.
Scientists exploring deep beneath the jungles of Mexico's
eastern Yucatán peninsula discovered the girl's remains
underwater alongside bones of more than two dozen beasts
including sabre-toothed tigers, cave bears, giant ground
sloths and an elephant relative called a gomphothere.
The girl - with her intact cranium and preserved DNA - was
entombed for eons in a deeply submerged cave chamber before
being discovered in 2007. The petite, slightly built girl -
about 4 feet, 10 inches tall (1.47m) - is thought to have
been 15 or 16 years old when she died.
She may have ventured into dark passages of a cave to find
fresh water and fallen to her death into what archaeologist
James Chatters, of the firm of Applied Paleoscience, one of
the leaders of the study, called an "inescapable trap" 30m
deep - a bell-shaped pit dubbed Hoyo Negro, "black hole" in
Chatters said the chamber - more than 40m below sea level -
was "a time capsule of the environment and human life" at the
end of the Ice Age.
The divers named her "Naia," a water nymph from Greek
mythology. One of the divers, Alberto Nava, recalled the
moment Naia was spotted - her skull resting atop a small
ledge. "It was a small cranium laying upside down with a
perfect set of teeth and dark eye sockets looking back at
us," Nava said.
The pit was dry when she fell but Ice Age glaciers melted
about 10,000 years ago, inundating the caves with water.
Tests determined she lived between 13,000 and 12,000 years
Scientists long have debated the origins of the first people
of the Americas. Many scientists think these hunter-gatherers
crossed the former land bridge between 26,000 and 18,000
years ago and subsequently pushed into North and South
America starting perhaps 17,000 years ago.
But the most ancient New World human remains have confused
scientists because, like Naia, they have narrower skulls and
other features different from today's Native Americans.
This led to speculation that these earliest New World people
might represent an earlier migration from a different part of
the world than the true ancestors of modern Native Americans.
But mitochondrial DNA - passed down from mother to child -
extracted from the girl's wisdom tooth showed she belonged to
an Asian-derived genetic lineage shared only by today's
This indicates cranial and other differences between the
earliest New World human remains and today's Native Americans
are due to evolutionary changes that unfolded after the first
migrants crossed onto the land bridge, the researchers said.
The study, led by the Mexican government's National Institute
of Anthropology and History (INAH) and supported by the
National Geographic Society, appears in the journal Science.