Post #29181 by inkylouise on Thu, Apr 3, 2003 11:27 AM

For Kon-Tiki Theory, Ray of Hope Is Dashed
By NICHOLAS WADE

The explorer Thor Heyerdahl insisted, contrary to all expert opinion, that Polynesia had been settled by people from South America. He hewed balsa logs with his own hands, persuaded five companions to join him and courageously sailed his raft the Kon-Tiki from Callao, Peru, to the Raroia atoll in Polynesia, a journey of 4,300 miles.

His imaginative voyage proved that ancient Incas could have traveled to Polynesia with the means that they had available. But did they in fact do so?

Experts said the languages had nothing in common, and the archaeological evidence suggests that the Polynesians originated somewhere in Southeast Asia.

Still, there are a few provocative signs of early contact between the Americas and Polynesia, like the existence in Polynesia of the sweet potato and the bottle gourd, dating from prehistoric times. Both are crops of South American origin.

A team of archaeologists and geneticists now reports another sign. On Rapa, a tiny Polynesian island near Tahiti, the team found that several men carried Y chromosomes with a DNA pattern distinctive to American Indians. Was it possible that the islands had been colonized first from South America and later by waves of immigrants from Southeast Asia, as the discredited Heyerdahl had said all along? (Heyerdahl died last year, at 87.)

The new finding is reported in The American Journal of Human Genetics by Dr. Matthew Hurles, an archaeologist at the University of Cambridge, and other English colleagues.

But before tying their colors to Heyerdahl's mast, they prudently analyzed the mitochondrial DNA, a genetic element passed down only in the female line, in their Rapan subjects. There were no signs of American Indian lineages of mitochondrial DNA, suggesting that there could not have been an ancient settlement of American Indians, because the female lineages should have survived as well as the male ones.

So the researchers hit the archives to see whether they could find any other explanation, and they chanced upon a curious tale.

In 1862 and 1863, they say, Peru tried to enter the slave trade. The effort was rapidly squashed by the weight of international disapproval, but not before 6,000 Polynesians had been kidnapped.

Some Polynesians, however, fought back. In January 1863, the Rapans were warned that the slaving ship Cora would arrive. When it did, they overpowered the crew members, taking most of them to Tahiti for trial. But some crewmen remained on Rapa, including three Chileans and a Mexican, according to the French-language newspaper Messager de Tahiti.

Meanwhile, the Peruvians decided to return the slaves whom they had improperly captured, though many had died from harsh labor or disease. A ship set out with 470 liberated slaves, but 439 died from disease, and their bodies were thrown overboard. The captain dropped off 15 survivors at Easter Island and the rest at Rapa.

More disasters followed. The repatriated Polynesians carried a disease, whether smallpox or dysentery, that devastated Rapa in 1864. The crew members of the slave ship were probably more resistant than the Polynesians. And that is why their chromosomes are quite common among residents today.

Despite having found the first traces of American Y chromosomes in Polynesia, Dr. Hurles and his colleagues are no nearer to explaining the prehistoric contacts that carried the sweet potato and bottle gourd to the islands.

The lesson of their study, the researchers said, is "the need to account for events in history before turning to prehistory."