A plastic copy of the skull of 9,000-year-old Kennewick Man. (Associated Press)

Genetic tests on one of the most important human skeletons ever found in North America have re-ignited a fierce debate over the rightful fate of the remains.The ancient skeleton of Kennewick Man became the focus of a bitter $5m court battle between the US government, which planned to return the bones to Native Americans for reburial, and scientists, who wanted to study the remains.In 2004, a US court ruled in favour of the scientists after it judged that Native American tribes had failed to prove their kinship with Kennewick Man.But now the story has taken an ironic twist. Genetic tests made possible by the ruling suggest Kennewick Man probably is Native American. Having rescued the bones for science, scientists have nudged them towards the grave."This is where all hell breaks lose," said Eske Willerslev, a world expert in ancient DNA who led the analysis at the University of Copenhagen in Denmark. "I am completely confident Kennewick Man is Native American. He is as much Native American as Native Americans living today."Jim Boyd, a member of the Confederated Tribes of the Colville Reservation in northern Washington, who fought for repatriation of the remains, said: "This is a happy time for us. We have maintained throughout that the Ancient One is a relative of ours, so these findings are wonderful for us.""We expect to have a fight, but we would like to see him buried very respectfully in a resting place where he should be. My own belief is that we will get the remains back," he added. But that is not likely, or justified, some scientists maintain.The near-complete skeleton of Kennewick Man was discovered by chance in 1996, when students stumbled upon a skull while wading through the Columbia river near Kennewick in Washington state.The skeleton had the police, archaeologists and the local coroner baffled. Kennewick Man did not look Native American. Adding to the mystery, his teeth were free from fillings and profoundly worn down: a clear dental signature of an ancient diet.Closer inspection of the bones revealed a sharp stone spearpoint wedged in the man's hip, placing him firmly in prehistory. The true age of the skeleton emerged soon after, when carbon dating of a bone fragment put the man at 9,000 years old.On hearing the age of the remains, the US Army Corps of Engineers, who manage the land where the skeleton was found, claimed ownership and blocked scientists from studying the bones. Local Native Americans then appealed to the corps to return the remains under US repatriation laws. The army corps, already in negotiations with the tribes over fishing rights and pollution problems, agreed.But the looming reburial of Kennewick Man distressed some scientists. One group, led by Douglas Owsley at the Smithsonian Institution in Washington DC, decided to sue the government in the hope of saving the remains for science. The US courts ruled in their favour in 2002, and again in 2004 when the government appealed the decision. Ordered to give the scientists access to the bones, the corps permitted 16 days for researchers to study the remains.The Smithsonian's research was brief but intense. It pointed to an unusual origin for Kennewick Man. His diet suggested he hunted along the coast, and was not from the region where he was found. From the size and shape of his skull, he appeared to be descended from the people who gave rise to modern Polynesians, the scientists said.But Willerslev now contests those conclusions. He commissioned researchers at the University of Zurich to reanalyse the skull measurements. The group concluded that it was impossible to say where Kennewick Man came from. The remains of one individual are simply not enough to go on, they found.Writing today in the journal Nature , Willerslev and his colleagues describe how they extracted and sequenced DNA from 200 grams of Kennewick Man's hand bone. When they compared the ancient DNA to samples taken from people around the world, they found the closest match with Native Americans, in particular the Colville tribe, which still lives in the region."Of all the Native American genome sequences we have, the Colville is the closest we have to Kennewick Man," Willerslev told the Guardian. "Our data show that the Colville come from same population as Kennewick Man." In other words, they are his direct descendants.But Owsley urges caution. Though impressed by the genetics in the study, he believes Willerslev is making claims his data cannot support."The whole Kennewick Man lawsuit was to try and make studies like this possible," Owsley told the Guardian. "Any time we gain additional genetic information from a very ancient skeleton is a very important advancement.""Where I really think they really overstep is when they focus on the descendants of Kennewick Man. It is extremely important to stress that when they try to link him to one particular tribe; in reality, he'll be linked to multiple groups in the Americas."Part of the problem is the paucity of DNA from ancient people to compare with that taken from Kennewick Man. A close match means little if many ancient people are not included in the analysis.Owsley said the new data do nothing to undermine the court decision of 2004. He said Kennewick Man still fails to meet the definition of a Native American in the Native American Graves Protection and Repatriation Act (NAGPRA). Under the Act, "Native American" means of, or relating to, a tribe, people, or culture that is indigenous to the United States.A challenge in court "would never stand up" Owsley said. "We don't know anything about his culture. We don't know who his people are. And we don't know where he's coming from.""I've worked on thousands of humans skeletons, and I've never worked on a set of remains that are as important in helping us understand this time period. There are people who, like myself, think this is one of America's most important findings. I think we need to take our time. We still don't know the full story," he added.Willerslev refused to share his own view on what should happen to the remains, but has spoken with the Colville tribe about his findings."They lost their legal case based on what I'd call poor scientific evidence," he told the Guardian. "They have been devastated ever since the ruling and they feel very strongly about reburying. They believe the spirit won't rest until it is reburied. I expect they will make a claim again."