New genetic study succeeds in reconstructing and mapping the population of Polynesian islands, the most isolated region on the planet

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23 Sep 2021 20:59 GMT

The researchers analyzed the DNA of more than 430 individuals belonging to various indigenous communities spread over 21 islands of the Polynesian archipelago, generating a detailed genetic profile of the population that inhabit this remote region of the Pacific.

For decades, the settlement of the islands that make up Polynesia has been the subject of study by a large number of scientists and, despite the fact that certain linguistic and archaeological studies have laid the foundations for understanding this process, this evolution has not has not been fully clarified. . However, a recent genetic study has shed new light on the migration of the first human groups that colonized the remote Pacific islands, which collectively are considered the most isolated place on the planet.

Thanks to the use of new techniques for genetic analysis of populations, a multidisciplinary research team has succeeded in reconstituting and mapping with precision the migratory sequence of the first colonizers of the island territories that make up Polynesia. A process which, according to experts, began with the migration of indigenous groups from Samoa to the Cook Islands, around AD 830, and ended between the 13th and 14th centuries with the colonies of the Marquesas Islands, Raivavae and Rapa Nui, also known as Easter Island.

During the study, academics collected genetic material from 430 individuals belonging to indigenous communities spread across 21 islands in the archipelago. The DNA samples were analyzed via high density genotyping platforms, identifying these molecular markers of Polynesian ancestry, which made it possible to generate a detailed genetic profile of the population that inhabit this remote region of the Pacific.

The results obtained show that the population of the islands does not follow a linear logic nor is it determined by the proximity between the island territories. In this sense, the scholars detail, the island of Rarotonga was populated around the year 830, and its inhabitants went to Tahiti, more than thousand kilometers far, in 1050, some 140 years before going to the Cook Islands (Aitu and Maueke), located less than 200 kilometers.

According to Alexander Ioannidis, co-author of the research, the results suggest that for about 250 years “Ambitious” expeditions set off from the small peripheral islands of the Tuamotu, east of Tahiti, to colonize Rapa Nui, the Marquesas and Raivavae, archipelagos separated by thousands of kilometers, but which are home to similar material cultures, such as the gigantic ones. monolithic sculptures, known as moai. “These statues are only found on islands which are closely genetically related,” he explained.

Since the settlement occurred within a short period of time, in about 17 generations, the linguistic and cultural changes between the different island populations are barely noticeable, so that studies focused on language and archaeological remains did not offer a concrete periodization of the migratory movement across the islands.

“The cultural triangle that encompasses hundreds of Polynesian islands is gigantic and there were few details of the routes followed by navigators. Now, from the genomic data of the people who currently live on these islands, we are able to infer the directionality of the change in allele frequencies, which helps us trace the path of this migration and even the dates on which they occurred, ”explained Andrés Moreno, co-author of the research recently published in Nature.

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