Europe's first inhabitants
LONDON (Jul 2, 1996 00:23 a.m. EDT) -- Europeans are descended from hunter-gatherers who first colonized the Continent 40,000 years ago, a new genetic analysis has shown.The study is likely to be the final nail in the coffin of Neanderthal Man, who occupied Europe for half a million years. No trace of Neanderthal lineage can be found in modern Europeans, supporting the view that the two groups did not interbreed and Neanderthals became extinct after occupying the Continent for half a million years.
More controversially, the analysis shows that the later immigration of farmers from the Middle East had relatively little effect. These people arrived less than 10,000 years ago, but their DNA is present in relatively small amounts in modern Europeans, no more than around 10-15 percent.
The analysis, published Monday in the American Journal of Human Genetics, comes from a team led by Dr. Bryan Sykes of the Institute of Molecular Medicine at Oxford and including scientists from Hamburg, University College London, Plymouth, and Newcastle.
They examined samples of DNA from populations across Europe, obtained from hair roots or blood samples. The form of DNA they studied, mitochondrial DNA, is passed down only through the maternal line and mutates at a known rate.
From the amount of variation in this type of DNA in a population it is therefore possible to work out the length of time that has elapsed since that population originated. The team found that the DNA in their samples could be classified into five broad groups, each with an origin at different times. The oldest group appears to have originated some 50,000 years ago, the youngest about 6,000 years ago.
By far the commonest groups, accounting for some 70 percent of the variations found in today's Europeans, date back considerably earlier than the invention of agriculture 10,000 years ago.
This suggests, say the authors, that the bulk of Europeans are descended from people who were here before the farmers began to arrive. There appear to have been two phases: first the colonisation of Europe up to 40,000 years ago and then a rapid expansion of population about 25,000 years ago, which may have been caused by new immigration or by a warmer climate.
The results indicate that agriculture came to Europe by a process of education rather than population displacement. The hunter-gatherers learned to cultivate crops from the incoming wave of farmers, but were not replaced by them.
These two groups then inter-bred, producing today's population mix. As
for the Neanderthals, they neither learned from the incomers nor bred
with them, losing out to modern man and being replaced totally by him.
