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Polynesia: Genes mark early settlement routes in the Pacific

Polynesia : The settlement of the Pacific

The greatest nautical adventure of mankind took place in the Pacific, where people have been hopping through thousands of kilometers of watery desert from lonely island to lonely island since the early Middle Ages. This has left traces in the genes of the locals to this day. by Jan Osterkamp  Easter Island © fotolia/Rüdiger Toebert (detail)

In the early Middle Ages, mankind set out to seek out the last unpopulated spots on the globe: Through the Pacific, seafarers hopped from island to island in seaworthy canoes and gradually reached all of Polynesia, New Zealand, the small islands in the middle of the ocean further east and finally even the remote Easter Island. Geneticists and archaeologists have long been investigating when and where people got to.

According to the current state of affairs, today's Polynesians are originally the descendants of people of the Lapita culture of Taiwan, who began around 3000 years ago to gradually head across larger islands from Papua New Guinea to Tonga, Samoa and Fiji. From there, they pushed across the vast deserts of water of the Pacific to the east at express speed & nbsp; & # 8211; possibly whenever the winds were particularly favorable for a spread.

With genetic analyzes of people living on the islands today, researchers have now succeeded in tracing the trail of the Eastern Polynesia pioneers in much more detail, as described in “Nature”. The population geneticists compared DNA samples from 430 people from all parts of Polynesia, which had been collected for earlier studies. The researchers looked for signs of the occurrence of a genetic peculiarity that occurs when small groups island hop: When pioneers repopulate an island, they become a founder population with a similar, rather small gene pool with low genetic diversity. The isolation in the new home creates a genetic bottleneck. Later offspring of this group & nbsp; & # 8211; maybe originally there are only a dozen to a few hundred people on a few canoes & nbsp; & # 8211; are therefore genetically clearly identifiable, and still today.

So you can understand on which islands the ancestors of the island, which is now home to an island, most likely once lived & nbsp; & # 8211; and on which one probably not. The analysis quickly made it clear that the groups on the distant islands did not mix with one another over and over again across the vast area: archaeological and linguistic studies have shown that individual islands were in contact with one another again and again. From a geographical point of view, however, the lines are mainly kept under one another, as the genetic analyzes show.

The groups then pushed forward from individually conquered islands, and this is how pedigrees of the lines of discovery emerged, which can be traced to this day. They can also be classified in terms of time by analyzing the lengths of the matching sequence fragments: In addition to the mere degree of relationship, it also becomes clear when which group is derived from which. The analysis first confirms what was previously assumed. Settlement of the smaller Pacific Islands from Samoa began around the year 800. The second oldest genetic trace can then be found on the main island of what is now the Cook Islands; from there people hopped in different directions from island to island. A line came to Rapa Nui around 1210.

Occasionally the pioneers seem to have taken routes that are not obvious at first glance. The genetic analysis confirms older archaeological hypotheses in one case. For example, the people on Rapa & nbsp; Nui, Raivavae and the Marquesas Islands in the East Pacific are related to each other & nbsp; & # 8211; all probably descend from a population that had populated the Tuamotu Archipelago. These island groups are not exactly neighboring and would have been easier to reach from other islands. Large stone sculptures such as the moai on Easter Island are known especially on the three archipelagos. Has a founding population passed on a common cultural tradition in which large sculptures play an important role? The genetic analyzes show that Easter Island was settled from the Tuamotu Island Mangareva. From the Tuamotus & nbsp; & # 8211; As on other Polynesian island groups, the religious areas of the marae are known, on which larger stone sculptures may have been placed as a further development.

The genes of today's residents of Easter Island, Raivavae and the Marquesas also show traces of a pre-modern age resulting relationship to people from South America. According to this, Polynesians could already be around the year & nbsp; 1100 & nbsp; & # 8211; when they began their last long journeys far east & nbsp; & # 8211; had more than fleeting contact with the American mainland. It was known that South Americans and South Sea islanders met after analyzing the genetic make-up from humans and chicken bones.

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