Y CHROMOSOME HELPS IDENTIFY EUROPE'S 'ADAM'
WebPosted Fri Nov 10 17:03:09 2000

WASHINGTON--Researchers studying patterns in the human Y chromosome say 
they have determined the likely ancestry of European males. 

 The Y chromosome, responsible for creating males, contains about 60 
million DNA base pairs. Changes in the pattern of these pairs are rare, 
but they have happened often enough to create a sequence that 
researchers were able to trace back hundreds of generations. 

 According to their study, some 80 per cent of European males share a 
single pattern, suggesting they had a common ancestor thousands of 
generations ago. The researchers think this man was one of the 
Paleolithic people who first migrated to Europe. 

 Peter Underhill, senior researcher at the Stanford Genome Technology 
Center and co-author of the study said the research supports conclusions 
from archeological, linguistic and other DNA evidence about the 
settlement of Europe by ancient peoples. 

 He says having several lines of evidence pointing to the same 
conclusions helps to strengthen theories about Europe's ancestors. 

 Variations on a theme 

 The Y chromosome pattern in this 80 per cent of European males has some 
slight differences that apparently developed among people who shared a 
common ancestor but were later isolated for many generations. 

 The theory goes that primitive, stone-age humans came to Europe, 
probably from Central Asia and the Middle East, in two waves starting 
40,000 years ago. 

 There weren't very many of them, and they were hunters and gatherers, 
using crudely sharpened stones for tools, and cooking over fires. 

 Later, about 24,000 years ago, the Ice Age began. Mountain-sized 
glaciers moved across most of Europe, causing the Paleolithic Europeans 
to retreat, separating into three distinct groups. These groups settled 
in what are now Spain, the Balkans and the Ukraine. 

 When the glaciers melted 16,000 years ago, the three tribes resettled 
the rest of Europe. Y chromosome mutations had occurred among the people 
in each of the ice age refuges, according to Underhill. These variations 
are also apparent in today's populations. 

 The remaining 20 per cent of Europeans have a Y chromosome pattern from 
a later migration. About 8,000 years ago, a more advanced people, the 
Neolithic, migrated to Europe from the middle East bringing agriculture, 
and, of course, their different Y chromosome pattern. 

 The research appears in November 10, 2000 Science magazine. 

 
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