Tracing generations
Native Americans, Polynesians shared DNA 800 years ago
that people from Peru had populated the remote Pacific islands, and wanted to show it was possible. But he only got it half-right, it seems.
“It is more likely that Polynesians reached the Americas, given their voyaging technology and demonstrated ability to cross thousands of miles of open ocean,” lead author Alexander Ioannidis, a postdoctoral researcher at Stanford University, told AFP.
Traveling in outrigger canoes, Polynesians established settlements across a vast area inside a triangle formed by the Hawaiian Islands, Easter Island and New Zealand.
Up to now, probably the most compelling evidence that preAmerican and Polynesian cultures intersected was the sweet potato.
“It is native to the Americas, yet it was also on islands thousands of miles away before European contact,” Ioannidis said.
Unwritten histories
Moreover, Polynesian words for the yellowish tuber are similar to those in indigenous American languages in the Andes.
But skeptics pointed out that sweet potatoes shoots might have made it half-way across the Pacific on their own, on a piece of driftwood, for example.
To look for possible points of convergence, researchers collected genetic data from 15 Native American groups along the Pacific coast of South and Central America, and from 17 Polynesian islands – more than 800 individuals in all.
“We looked for long sequences of DNA with exactly the same code,” said Ioannidis.
The match-up with indigenous groups in Colombia and Ecuador was unmistakable, confirmed both by traditional statistical methods, and new “big data” machine-learning techniques.
The genetic material also revealed the timing of the encounter.
With successive generations, DNA inherited from each parent undergoes “recombination,” whereby pieces of DNA from the mother and father are broken off and fused together.
“By measuring the length of the small Native American pieces of DNA in Polynesians, we can estimate how many generations ago the contact occurred.”
The date that emerged was 1200, around the time the crusades sacked Constantinople.
Among the long-standing articles of belief dismantled by the new findings is the contention that Rapu Nui – better known as Easter Island – was the first place where the two cultures literally came face-to-face.
New computational methods will help scientists and scholars uncover previously inaccessible stories from the past, said Moreno-Estrada.
“Much of history has relied on written accounts, which are generally controlled by, and focus on, those who rule,” he said.
“Genetics and data science are now allowing us to tell the perhaps even more incredible – and no less true – stories of the rest of humanity.
“That’s what really motivates me,” he added.