DNA offers a new look at how Polynesia was settled

I found an interesting article in the Science News written by Bruce Bower about the Polynesian voyager in the Southsea. Bower wrote earlier already some more intersting  article about this. I will put them all in this post.

I can still remember very well, when as a young child, I leafed through the old books of foreign countries and saw a black and white photo, including sketches of these huge, monster stone sculptures from Easter Island. It was impressive. Even if I still see this today, I have to ask myself who were these people who created such sculptures? I don’t know anything else in the South Seas where such stone figures were built? Do you? Admirable. Even today we still don’t know the purpose, the meaning of these statues. I think it’s just terrific, almost terrifying in a way …..

Voyagers migrated to islands sprinkled across a large area of the Pacific within about 500 years
image of a row of statues on Easter Island
Eastern Polynesia’s settlers rapidly voyaged across a vast area starting nearly 1,200 years ago, a new genetic study finds. Groups with a shared ancestry may have carved massive statues on easternmost islands, including these on Easter Island. Atlantide Phototravel/Getty Images Plus

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Polynesian voyagers settled islands across a vast expanse of the Pacific Ocean within about 500 years, leaving a genetic trail of the routes that the travelers took, scientists say.

Comparisons of present-day Polynesians’ DNA indicate that sea journeys launched from Samoa in western Polynesia headed south and then east, reaching Rarotonga in the Cook Islands by around the year 830. From the mid-1100s to the mid-1300s, people who had traveled farther east to a string of small islands called the Tuamotus fanned out to settle Rapa Nui, also known as Easter Island, and several other islands separated by thousands of kilometers on Polynesia’s eastern edge. On each of those islands, the Tuamotu travelers built massive stone statues like the ones Easter Island is famed for.

That’s the scenario sketched out in a new study in the Sept. 23 Nature by Stanford University computational biologist Alexander Ioannidis, population geneticist Andrés Moreno-Estrada of the National Laboratory of Genomics for Biodiversity in Irapuato, Mexico, and their colleagues.

The new analysis generally aligns with archaeological estimates of human migrations across eastern Polynesia from roughly 900 to 1250. And the study offers an unprecedented look at settlement pathways that zigged and zagged over a distance of more than 5,000 kilometers, the researchers say.

“The colonization of eastern Polynesia was a remarkable event in which a vast area, some one-third of the planet, became inhabited by humans in … a relatively short period of time,” says archaeologist Carl Lipo of Binghamton University in New York, who wasn’t involved in the new research.

Improved radiocarbon dating techniques applied to remains of short-lived plant species unearthed at archaeological sites are also producing a chronology of Polynesian colonization close to that proposed in the genetic study, Lipo says.

In the new investigation, researchers identified DNA segments of exclusively Polynesian origin in 430 present-day individuals from 21 Pacific island populations. Island-specific genetic fingerprints enabled the scientists to reconstruct settlement paths, based on increases in rare gene variants that must have resulted from a small group moving from one island to another and giving rise to a new, larger population with novel DNA twists. Comparisons of shared Polynesian ancestry between pairs of individuals on different islands were used to estimate when settlements occurred.

In an intriguing twist, the DNA evidence “is consistent with the [statue] carving tradition arising once in a single point of common origin, likely the Tuamotu islands,” Moreno-Estrada says. Polynesian ancestry on all the islands with massive statues traces back to the one island in the Tuamotus where the researchers were able to obtain Indigenous peoples’ DNA.

The Tuamotus include nearly 80 islands situated between Tahiti to the west and other islands to the north and east where settlers carved statues. The latter outposts consist of the Marquesas Islands, Mangareva and Rapa Nui. Another late-settled island where inhabitants carved statues, Raivavae, lies southwest of the Tuamotus.

Settlers reached the island of Mataiva in the northern Tuamotus by about 1110, the researchers suggest. Statue makers navigated northward and eastward from Mataiva or perhaps other Tuamotu islands to as far east as Rapa Nui — eventually curving back west before arriving at Raivavae — around the same time as an earlier DNA study suggests eastern Polynesians mated with South Americans (SN: 7/8/20). (It’s not clear whether South Americans crossed the ocean to Polynesia or Polynesians traveled to South America and then returned.)

Ioannidis and colleagues’ conclusions generally support prior scenarios of Polynesia’s settlement, but some disparities exist between their genetic evidence and earlier archaeological and linguistic findings, writes archaeologist Patrick Kirch of the University of Hawaii at Manoa in a commentary published with the new study.

For instance, the new DNA analysis overlooks extensive contacts that occurred across eastern Polynesian in its early settlement stages, Kirch says. Analyses of closely related eastern Polynesian language dialects and discoveries of stone tools that were transported from one island to another point to substantial travels and trading throughout the region during that time.

Kirch, who has previously suggested that these long-distance contacts in eastern Polynesian influenced stone carving traditions, calls the new proposal that people with a shared ancestry brought stone carving to Rapa Nui and other islands “a provocative hypothesis.”

And there’s still no answer to one major question regarding the settlement of the islands, says molecular anthropologist Lisa Matisoo-Smith of the University of Otago in Dunedin, New Zealand, who didn’t participate in the new research. No current line of evidence can resolve the mystery of why, after spending nearly 2,000 years on Samoa, Tonga and Fiji, Polynesians began voyaging thousands of kilometers eastward in search of new lands.

 

Easter Islanders sailed to Americas, DNA suggests

Sea crossings occurred well before European contact, genetics of present-day people indicates
Easter Island statue
HEAD EAST People living on Easter Island, known for its carved giant stone statues, sailed to and from the Americas before Europeans reached their South Pacific home, new genetic evidence suggests. Natalia Solar
Bruce BowerBruce Bower

 

Behavioral Sciences Writer
Bruce Bower has written about the behavioral sciences since 1984. He often writes about psychology, anthropology, archaeology and mental health issues. Bruce has a master’s degree in psychology from Pepperdine University and a master’s degree in journalism from the University of Missouri. Following an internship at Science News in 1981, he worked as a reporter at Psychiatric News, a publication of the American Psychiatric Association, until joining Science News as a staff writer. In 1996, the American Psychological Association appointed Bruce a Science Writer Fellow, with a grant to visit psychological scientists of his own choosing. Early stints as an aide in a day school for children and teenagers with severe psychological problems and as a counselor in a drug diversion center provided Bruce with a surprisingly good background for a career in science journalism.

Hail the Hokule’a, Twin Hulls of Heaven

Sam Law

By Sam Low  (Thursday, February 4, 2016 )

Four years ago today, Hokule’a, a faithful replica of an ancient sailing vessel used by the Polynesians to explore and settle the entire Pacific a thousand years before Europeans even knew that vast ocean existed, was sailing toward Martha’s Vineyard for a three-day visit. As I was involved with planning that visit, I will be celebrating this fourth year anniversary on this page with a variety of posts.

 

 


To a modern sailor’s eye, she appears strange. Her twin hulls are joined by laminated wooden crossbeams and fastened to them by six miles of rope lashings woven into complex patterns reminiscent of the art of M.C. Escher. A deck is lashed over the crossbeams. The hulls rise up sharply at bow and stern and terminate in a graceful arc, called a manu, where wooden figures with high foreheads and protruding eyes, the aumakua or guardian spirits, stare out over an empty sea. Viewed from above, the canoe’s strangeness is dispelled. She looks like a catamaran.

Hokule’a is a replica of the vessels used by Polynesians to settle one-third of our planet a thousand years before Europeans knew the Pacific Ocean existed. Launched in 1975, she has sailed 150,000 miles, following the routes taken by intrepid Polynesian explorers, navigated always as they would have done — without instruments or charts — by relying instead on signs in the stars, waves and flight of birds. In July, Hokule’a will visit Martha’s Vineyard on a voyage around the world to malama honua, care for Planet Earth.

Hokule’a’s shape is ancient but her construction is not. A thousand years ago, her sails would have been woven from Pandanus fronds, but no one knows how to do that today, so they are made of Dacron. Her hulls are fiberglassed marine plywood because the art of carving such canoes from live wood has vanished along with the ancient canoe makers, the kahuna kalai wa’a. She is a performance replica, designed to perform like an ancient vessel by using plans made by European explorers of the canoes they encountered in the 18th century.

“We wanted to test the theory that such canoes could have carried Polynesian navigators on long voyages of exploration throughout the Polynesian triangle,” said navigator Nainoa Thompson, “We wanted to see how she sailed into the wind, off the wind, how much cargo she could carry, how she stood up to storms. Could we navigate her without instruments? Could we endure the rigors of long voyages ourselves? Frankly, that was enough of a challenge. It didn’t matter if the canoe was made of modern materials as long as she performed like an ancient vessel.”

Hokule’a is 62 feet long, displaces about eight tons and carries a cargo, including her crew, of six tons. Sailing with a strong wind behind her, she rockets along at 15 knots. Sailing into the wind, on a voyage between Hawaii and Tahiti, she averages about five knots and a 2,400-mile journey usually takes about 25 days.

We sleep in the hulls, in small compartments about four feet wide and six long, covered by a tent stretched over the handrails. We cook on deck using a two-burner propane stove encased in a waterproof box. To go to the bathroom you walk aft, crawl under the handrails, stand on a narrow catwalk and hang on.

I first sailed aboard Hokule’a in 2000, on a voyage from Tahiti to Hawaii. Five years earlier, I had made the same voyage on a 40-foot sloop of impeccable modern design. The voyage turned out to be a severe test of endurance and patience. The sloop heeled over in the trade winds — about 30 degrees from vertical — and thrashed her way through heavy swells. We lived in a canted, pitching world for three weeks, emerging from that experience thrilled but exhausted.

My voyage aboard Hokule’a was quite different. A sailing vessel with a single hull like the sloop heels away from the wind, but Hokule’a distributes the wind’s torque across two hulls so she does not heel, providing a stable and comfortable living platform in even the most terrific of winds. And her hulls are lean and narrow, so she does not pound into the waves. She slices through them with what can only be described as grace. The contrast in oceangoing comfort between the modern sloop and the Hokule’a is like that on land between a truck and a Cadillac.

There are other advantages as well. Our navigators steer the canoe by the rising and setting stars and find their latitude by measuring a star’s altitude with their hands, or observing pairs of stars whirling together across the meridian over the north or south celestial poles. The open deck of the canoe, uncluttered by superstructure, permits clear sightlines all around — an open-air observatory. Her twin hulls also provide an opportunity for her crew to deploy other subtle human senses to determine direction at sea. Hokule’a invites her crew to dance and she dances one way if she’s encountering swells from forward and another way in swells from abeam. Her motion differs if she’s running with the wind or sailing into it. The possible combinations are infinite, so the choreography is complex. Hokule’a demands attention from her human partners. If they falter, she reminds them. If they turn off course and into the wind she slows and shakes her sails. “Listen to me,” she says, “Can you hear it?” An alert helmsman knows to push the canoe’s steering paddle down to help her fall off. If the helmsman turns downwind she speeds up and pulls at her tiller. “Pay attention,” she says. All these are clues to maintaining a steady course, an important task for any navigator but particularly so for one finding his way without instruments. Determining longitude depends on dead reckoning, and dead reckoning, in turn, depends on keeping track of your course.

Catamarans are considered a recent innovation inspired by racing sailors seeking speed. But in Polynesia, such craft were invented thousands of years ago. Limited by stone and shell tools and the lack of iron fastenings, Polynesians could not fashion large European style plank-on-frame ships. Small outrigger canoes would not be seaworthy for long voyages, nor could they carry the cargo and people necessary to settle new islands. Large outrigger canoes would be unwieldy. So someone, thousands of years ago, thought of bridging two canoes with a solid deck. An advanced sailing craft was born out of necessity confronting the limits of a primitive technology.

Part three of a series. To learn more about Hokule’a and her voyage around the world, visit hokulea.com. To learn more about her visit to Martha’s Vineyard you may contact Sam Low at samfilm2@gmail.com.