4 Oct 2016

DNA confirms the first Pacific migrants came from Asia

From Jesse Mulligan, 1–4pm, 1:27 pm on 4 October 2016

For the first time the DNA of ancient Pacifica people has been sequenced, revealing where they came from before migrating to the Pacific.

Researchers including, Professor Murray Cox of Massey University, sequenced the DNA of skeletons from 3000 years ago in Vanuatu and Tonga.

A 3000-year-old burial in the Pacific Island nation of Vanuatu is a source of one of the ancient DNA samples.

A 3000-year-old burial in the Pacific Island nation of Vanuatu is a source of one of the ancient DNA samples. Photo: Massey University

It was only about 3000 to 4000 years ago that farming populations from mainland Asia started moving out into the islands of the Pacific, Polynesia and ultimately New Zealand.

The sequencing reveals they were from Asian farming groups rather than having, as was previously suspected, Papuan ancestry.

“The individuals that we’re studying the DNA from are within maybe a generation or two of the very first people to make that jump out into the ocean,” Prof Cox says.

There were already people living in New Guinea the Papuans so when these farming populations came down from China and through Indonesia and the Philippines, the thought was that they would have intermarried with the people who were already there.”

It was thought it was a racially mixed group that journeyed out into the Pacific.

“This new evidence shows that’s not the case, and that farming populations came down from Asia and swept into the Pacific very quickly, and largely unmixed,” he says.

The research also shows a pattern of marriage previously unknown; Asian women actively sought out Papuan men as partners.

“It does look from the genome like there was a particular direction to it, so we had Asian women preferentially marrying Papuan men. We’re not entirely sure why, but it’s very clear that’s what happened.”

He said the research is the first real glimpse into how the genomes of Maori and Pacifica developed over time and that could help us understand some of the health problems prevalent in these populations.

“When these Asian groups moved out into the Pacific there was selection, really strong selection, for particular genes such as fat storage – if you’re voyaging for long periods of time you want to store fat - but today that’s not a good thing

“That‘s why we have high levels of obesity and diabetes in modern Pacific populations.”