New Study Reveals Remarkable Genetic Diversity among Papuan New Guinean Peoples

An international team of researchers led by the Wellcome Trust Sanger Institute has analyzed genome-wide data of 381 individuals from 85 language groups in Papua New Guinea and found that different groups within the country are genetically highly different from each other. The research is published in the journal Science.

Papua New Guinea was likely a stepping stone for human migration from Asia to Australia. Bergstroem et al performed genome-wide single-nucleotide polymorphism genotyping on 381 individuals from 85 language groups in Papua New Guinea and found a sharp divide originating 10,000 to 20,000 years ago between lowland and highland groups and a lack of non-New Guinean admixture in the latter. This photo shows drummers and dancers from each village on the beach of Port Moresby, the capital and largest city of Papua New Guinea. Image credit: Steve Jurvetson / CC BY 2.0.

The island of New Guinea contains some of the earliest archaeological evidence for modern humans outside of Africa, dating back to 50,000 years ago.

About 10,000 years ago, systematic plant cultivation was developed in its central mountain range, coinciding with similar, independent developments in the Near East, East Asia, and the Americas.

Today, the country of Papua New Guinea occupies the eastern half of the island and northern Island Melanesia and is the most linguistically diverse country in the world, with approximately 850 domestic languages spoken (account for over 10% of the world’s total).

To discover if the linguistic and cultural diversity was echoed in the genetic structure of the population, Sanger Institute researcher Anders Bergström and co-authors studied the genomes of 381 Papuan New Guinean people from 85 different language groups within the country.

The scientists looked at more than a million genetic positions in the genome of each individual, and compared them to investigate genetic similarities and differences.

They found that groups of people speaking different languages were surprisingly genetically distinct from each other.

“Using genetics, we were able to see that people on the island of New Guinea evolved independently from rest of the world for much of the last 50,000 years,” said senior author Dr. Chris Tyler-Smith, also from the Sanger Institute.

“This is the first large-scale study of genetic diversity and population history in Papua New Guinea,” Dr. Bergström added.

“Our study revealed that the genetic differences between groups of people there are generally very strong, often much stronger even than between major populations within all of Europe or all of East Asia.”

“We found a striking difference between the groups of people who live in the mountainous highlands and those in the lowlands, with genetic separation dating back 10,000-20,000 years between the two,” said co-author Professor Stephen J. Oppenheimer, from the University of Oxford.

“This makes sense culturally, as the highland groups historically have kept to themselves, but such a strong genetic barrier between otherwise geographically close groups is still very unusual and fascinating.”

Human evolution in Europe and Asia has been greatly influenced by the development of agriculture around 10,000 years ago.

When small bands of hunter-gatherers settled into villages and started farming, they expanded and over time gave rise to more genetically homogenous societies.

However, despite the independent development of agriculture in Papua New Guinea at about the same time, the same process of homogenization did not occur here.

This may indicate that other historical processes in Europe and Asia, such as the later Bronze and Iron Ages, were the key events that shaped the current genetic structure of those populations.

“This study allows us to glimpse a different version of human evolution from that in Europe and Asia, one in which there was agriculture but no later Bronze Age or Iron Age,” Dr. Tyler-Smith said.

“Papua New Guinea might show the genetic, cultural and linguistic diversity that many settled human societies would have had before these technological transformations.”

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Anders Bergström et al. 2017. A Neolithic expansion, but strong genetic structure, in the independent history of New Guinea. Science 357 (6356): 1160-1163; doi: 10.1126/science.aan3842