Where We Come From
Recent advances in genetics are starting to illuminate the wanderings of early humans
[Map is not available.]
By comparing mutations in the DNA of people who live in different parts of the world, geneticists are developing new theories about how humans populated Earth. The evidence points to a common African origin about 150,000 years ago. Much of the work has been based on maternal lines.
The first Europeans
Migrants arrived from the Near East as early as 50,000 years ago. The population shrank drastically during the last Ice Age 20,000 years ago, then rebounded. About 9,000 years ago, migrants from the Middle East moved north along with the spread of agriculture.
Many paths through the Middle East
Humans journeyed from Africa into the Middle East about 75,000 years ago. Over thousands of years, in multiple migrations, they spread east into Asia and northwest into Europe.
Africa, the ancestral home
The DNA of present-day Africans is more diverse than that of people on other continents, indication that humans have lived there longest. Traces of ancient African genes can be found in everyone living today.
Roots in Central Asia
All Asians derived from two common roots, with some lineages more frequent in southern Asia (Vietnamese, Malays, New Guineans) and others more prevalent in the north (Tibetans, Koreans, Siberians).
The Australian enigma
Modern humans traveled to Australia by boat 40,000 to 60,000 years ago. One theory suggests that they followed the southern Asian coast, mastering boat building along the way.
A bridge to the New World
The first inhabitants of the New World migrated from central Siberia 20,000 to 30,000 years ago along the Bering land bridge. They may have been joined by a second migration 15,000 years ago that skirted the coast. Na-Dene people, who include the Athabascans, Apaches, and Navajos, are genetically distinct from the first American Indians, and came from northern Siberia about 9,000 years ago. Eskimos and Aleuts arrived 4,000 to 6,000 years later.
Along the Andes to Tierra del Fuego
The earliest migration swept from Siberia to Tierra del Fuego, traveling along the Andes. Another route curved farther east, to present-day Brazil.
The X factor
A small group of Indians near the Great Lakes has a lineage (haplogroup "X") unlike those of other American Indians, but related to a European strain. Some archaeologists think that the colonists came from Iberia about 15,000 years ago, crossing the North Atlantic ice pack to Greenland. Others believe the X factor is the remnant of a vanished Asian lineage.
For most of the past 65,000 years, sea levels have been lower than today. During the last Ice Age 20,000 years ago, sea levels were about 400 feet lower.
[Map labels] Europe; Africa; Asia; Australia; Oceania; North America; South America
Key:
Dotted arrows show hypothetical routes.
Colored arrows represent separate genetic lineages.
Scale: Major migrations in thousands of years before present.
Ancient coastlines
[Artifact captions]
Venus of Lespugue
Found: Lespugue, France
Dated: 26,000 years ago
Horse pendant
Found: Sungir, Russia
Dated: 25,000 years ago
Stone tools
Found: Cactus Hill, Virginia
Dated: 15,000 to 18,000 years ago
Throwing stone
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