Huge genetic diversity among Papuan New Guinean peoples revealed

The first large-scale genetic study of people in Papua New Guinea has shown that different groups within the country are genetically highly different from each other. Scientists at the Wellcome Trust Sanger Institute and their colleagues at the University of Oxford and the Papua New Guinea Institute of Medical Research reveal that the people there have remained genetically independent from Europe and Asia for most of the last 50,000 years, and that people from the country’s isolated highlands region have been completely independent even until the present day.

Traditional Enga cultural show in Wabag, Papua New Guinea 
[Credit: Michal Knitl/Shutterstock]

Reported in the journal Science, the study also gives insights into how the development of agriculture and cultural events such as the Bronze or Iron Age could affect the genetic structure of human societies.

Papua New Guinea is a country in the southwestern Pacific with some of the earliest archaeological evidence of human existence outside Africa. Largely free from Western influence and with fascinating cultural diversity, it has been of enormous interest to anthropologists and other scientists seeking to understand human cultures and evolution.

Male Huli tribe member in Tari area of Papua New Guinea in traditional clothes and face paint 
[Credit: Amy Nichole Harris/Shutterstock]

With approximately 850 domestic languages, which account for over 10 per cent of the world’s total, Papua New Guinea is the most linguistically diverse country in the world. To discover if the linguistic and cultural diversity was echoed in the genetic structure of the population, researchers studied the genomes of 381 Papuan New Guinean people from 85 different language groups within the country.

The researchers 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.

Woman of a Papuan tribe in traditional clothes and coloring in New Guinea Island 
[Credit: Byelikova Oksana/Shutterstock]

Anders Bergström, the first author on the paper from the Wellcome Trust Sanger Institute, said: "This is the first large-scale study of genetic diversity and population history in Papua New Guinea. 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."

Professor Stephen J. Oppenheimer, second author of the paper from the Wellcome Trust Centre for Human Genetics, University of Oxford, said: "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. 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."

Locations of people studied from Papua New Guinea. Each language group is represented by a circle; the area indicates
 the number of genotyped individuals, and the color indicates the top-level language phylum. The study found that 
people speaking different languages were strongly genetically distinct from each other 
[Credit: Science doi: 10.1126/science.aan3842]

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 (similar) 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.

Dr Chris Tyler-Smith, corresponding author on the paper from the Wellcome Trust Sanger Institute, said: "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. 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. Papua New Guinea might show the genetic, cultural and linguistic diversity that many settled human societies would have had before these technological transformations."

Source: Wellcome Trust Sanger Institute [September 14, 2017]

Read More

Scientists tracing ancient Aboriginal fire practices on remote Tasmanian island unearth fresh timelines

A core sample taken from a remote Tasmanian island suggests Aboriginal people were using fire management on the island at least 41,000 years ago, experts have said. The findings by a joint project involving the Tasmanian Aboriginal Centre (TAC) and scientists could provide insight into how people adapted to changing climates.

The wetland on lungtalanana/Clarke Island is revealing information about environmental and fire history
[Credit: Andry Sculthorpe]

The TAC invited fire ecologist David Bowman and Australian National University natural history professor Simon Haberle to lungtalanana/Clark Island in Bass Strait to conduct research after it was ravaged by fire in 2014.

They took a core sample from a lake on the island which contained charcoal and pollen. From that they were able to reconstruct the island's fire history by determining how often vegetation had burnt over thousands of years.

"We found a lake which had superb organic sediments in the base and we assumed that they were just from the last 10,000 years," Professor Bowman said. "We radiocarbon dated the sediments and we discovered, to our amazement, that these sediments actually stretch back to 40,000 years. We found a site which is quite unique in southern Australia and indeed the southern hemisphere."

Fire ecologist David Bowman is working with Andry Sculthorpe from the Tasmanian Aboriginal Centre 
[Credit: ABC News, Rhiannon Shine]

Professor Haberle said the radiocarbon dating suggested fire management had occurred on the island at least 41,000 years ago. He said the core sample showed fire regimes on lungtalanana/Clark Island had changed substantially over that period.

"Part of that change was really due to the landscape management activities of Tasmanian Aboriginal people as they lived on those islands and used fire as a tool to manage the landscape," he said. "What we see is that over most of the period of the record, frequent and low-intensity fires occurred on the island. This can really only happen through regular burning of the vegetation, most likely because of people lighting those fires and managing the landscape."

Fires 'catastrophic after colonisation'

Professor Haberle said when Tasmanian Aboriginal people left the island the fires became more intense.

Map showing Clarke Island [Credit: Google Maps]

"When Europeans arrive there is a change in the fire regime and there are many very strong fires and in many cases catastrophic fires have occurred in the recent past," he said. "Those fires are a result of the kind of changes in the land management strategy."

Professor Bowman said the findings were significant and could provide insight into how people adapted to changing climates.

"Finding a sediment trap with such antiquity is absolutely astonishing with huge interest to interrogate," he said. "Scientists have looked at various sediment traps but nothing really of the quality and the time depth in southern Australia. We are terribly excited about this core."

The TAC has been rekindling traditional burning on its land for the past three years. Heritage project officer Andry Sculthorpe said the results from lungtalanana/Clark Island were important, though not surprising.

Researchers (left to right) Aine Nicholson, ANU professor Simon Haberle and Andry Sculthorpe inspect a core sample 
[Credit: David Bowman]

"When you actually see it in diagrams and through evidence collected about how those people may have been living there, and some of the landscape change, it is really interesting," he said. "It gives a deeper time scale to how things were in the past and how we can relate that to what we could do today. Fire is something that was always used by Aboriginal people to shape the environment and to keep country healthy."

Lessons from ancient culture: academic

Professor Bowman said traditional burning should play a greater role in today's fire mitigation.

"This would be, I think, a really great aspiration for Tasmania - to help a group of people who have had their culture disrupted by colonisation to rekindle their traditions and actually serve their society, our society, by making flammable, dangerous environments much safer," he said.

"This is getting quite urgent now because of the deteriorating climate conditions. We must learn from the past, we must learn from the first Australians. They obviously did something very clever, that they were able to sustainably coexist in a very flammable environment."

The group plans to return to the island before the end of the year to conduct further research, and use the findings to educate and train the next generation.

Author: Rhiannon Shine | Source: ABC News Website [September 12, 2017]

Read More