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 Scientists said on Thursday 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 saber-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 (1.47 meters) - 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
freshwater and fallen to her death into what archeologist James
Chatters of the firm of Applied Paleoscience, one of the leaders of
the study, called an "inescapable trap" 100 feet (30 meters) deep -
a bell-shaped pit dubbed Hoyo Negro, "black hole" in Spanish.
Chatters said the chamber - more than 135 feet (40 meters) below sea
level - was "a time capsule of the environment and human life" at
the end of the Ice Age.
WATER NYMPH
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 ago.
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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 Native Americans.
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.
(Editing by Matthew Lewis)
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