By Roger Highfield, Science Editor, in Washington DC

EUROPEANS colonised America up to 30,000 years ago, perhaps by crossing the Atlantic, according to a genetic analysis of native Americans that sheds light on their origins.

By studying the DNA in “power packs’ of cells called mitochondria, scientist can compare populations to reveal evidnece of ancient migrations, the American Association for the Advancement of Science was told.

Such work shows four main lineages in native Americans which can be traced to Siberia and north-east Asia, notably in Baikal and Altai-Sayan.

However, a fifth – more minor – founding lineage, called haplogroup X, can be traced to Europe, and is found in North American populations, said Dr Theodore Schurr of Southwest Foundation for Biomedical Research in San Antonio, Texas.

"This is one of the intriguing findings that we have come across recently,” said Dr Schurr. “These data imply that haplogroup X was present in the New World long before Europeans first arrived in the New World, before Columbus or the Vikings or anybody else.”

The find has led to some speculation that ancient people crossed the Atlantic from the Old World, because evidence of the group has not so far been found in Asia, though he stressed that not all central Asian groups had been analysed.

Dr Schurr said: “Haplogroup X was brought to the New World by an ancient Eurasian population in a migratory event distinct from those bringing the other four lineages to the Americas.”

The haplogroup X occurs most among Algonkian – speaking groups such as the Ojibwa, and has been detected in two pre-Colombian north American populations.
Today,haplogroup is found in between two and four per cent of European populations, and in the Middle East, he said, particularly in Israel.

The complex origins of the first Americans has also been highlighted by an analysis of thousands of skulls from around the world.

A team of anthropologists from the University of Michigan found that the study confirmed the complex origins of native Americans that have been suggested by recent archeological and genetic studies.

Using comparisons of thousands of ancient and modern skulls, collected over a period of 20 years and containing new data from Mongolia that became accessible just last summer, Prof Loring Brace showed how the native inhabitants of the Western Hemisphere fit into several different groups based on craniofacial patterns.

Their studies show that descendants of the first humans to enter the New World, including natives of Mexico, Peru, and the southern United States, have no obvious ties to any Asian groups. “This could be because they have been separated from their Asian sources for the longest period of time.” he said.

A second group – included the Blackfoot, Iroquois and other tribes from Minnesota, Michigan, Ontario, and Massachuesetts – was descended from the Jomon, of the prehistoric people of Japan. The Inuit appear to be a later branch from that same Jomon trunk. Tribal groups who lived down the eastern seaboard into Florida share this origin, according to Prof Brace.

Another group, originating in China and including the Athabascan-speaking people of the Yukon drainage of Alaska and north-west Canada, spread as far south as Arizona and northern Mexico. “Their craniofacial configuration allies them more closely to the living Chinese than to any other population in either hemisphere,” he said.