University of Otago – Ōtākou Whakaihu Waka researchers have helped bring clarity to the great migration of early Pacific pioneers, considered to be ancestors of many Pacific people including Māori.
In a new study published in Nature Ecology and Evolution, a group of international researchers involving several from Otago have recovered the first ancient genomes (aDNA) from Papua New Guinea and the Bismarck Archipelago – unlocking genetic insights from a region as culturally rich as it is historically pivotal.
Combining aDNA with dietary evidence and linguistics, the study reveals how the pre-colonial coastal communities were surprisingly genetically diverse from each other and suggests many cultural groups did not intermarry for some time.
Dr Monica Tromp
Co-author Dr Monica Tromp from Southern Pacific Archaeological Research, in the Archeology Programme, says aDNA acts like a time machine, revealing how people lived and interacted thousands of years ago – and how those ancient connections still influence our world today.
"This groundbreaking research reveals something remarkable: Pacific Island cultures were far more diverse and complex than we ever imagined.
"Rather than being one unified group, these ancient communities represented a rich tapestry of different cultures and peoples."
New Guinea, settled over 50,000 years ago, served as a vital launch point for early seafaring journeys into the wider Pacific – a chapter in human history marked by extraordinary navigational feats.
About 3,300 years ago, the Lapita people – considered the earliest ancestors of many Pacific people, including Māori – settled in the Bismarck Archipelago, which became the cradle of the Lapita cultural complex.
The seafaring peoples were renowned for their intricate pottery and horticultural practices and embarked on voyages that would reach as far as Vanuatu, Tonga, and Samoa.
Yet until now, the genomic legacy of these early Pacific pioneers – and the islands they first called home – had remained unexplored, Dr Tromp says.
"They were some of the world's greatest explorers and navigators, setting sail into the endless blue horizon centuries before Europeans ever dared venture far from their own coastlines."
What makes the study particularly exciting is that it shows how far scientific technology has advanced, she says.
"The DNA analysis that made these discoveries possible would have been completely impossible just a decade ago.
"Hot, humid tropical climates typically destroy genetic material, but new techniques have opened up entirely new chapters of human history that were previously lost to us."
One of the study's most striking findings is the presence of individuals with completely Papuan genetic signatures on the island of Watom in the Bismarck Archipelago, where missionaries found the very first Lapita-style pottery in the early 20th century.
The individuals excavated on the island are all younger than evidence for the arrival of the Lapita Cultural Complex. One of these individuals additionally displays a rare case of cultural cranial modification, suggesting the co-occupation of the island by genetically and culturally different groups.
Co-lead author Dr Rebecca Kinaston, from BioArch South, says the researchers' analysis reveals a fascinating picture of the earliest encounters in the Bismarck Archipelago.
"Despite the co-occupation, it seems the different groups didn't mix for a long time, which is quite unusual for human encounters."
The delay in intermarriage and the presence of people with Papuan ancestry inform on a debated matter in Pacific human history: Did the first settlers in the remote islands of Western Remote Oceania arrive unmixed and, followed by people from New Guinea, mix on the islands?
The new findings support previous studies, suggesting this is a likely scenario, and informing on the seafaring capabilities of Papuan ancestors, Dr Kinaston says.
The analysis of two geographically close communities inhabiting the South Coast of Papua New Guinea between 500 and 150 years ago proved to be particularly interesting, she says.
"Surprisingly, their ancestries started diverging 650 years ago, despite the absence of geographical borders.
"This divergence suggests the communities were shaped by distinct interaction spheres and cultural influences, with implications for our understanding of ancient trade networks and social dynamics."
The co-authors say the publication of these ancient genomes marks a significant step forward in understanding the genetic diversity and historical dynamics of Papua New Guinea and the wider Pacific.
