New AI research clarifies the origins of Papua New Guineans

A team of European researchers shed new light on the genetic origins of Papua New Guineans. Using advanced artificial intelligence (AI) tools, the team demonstrates that Papua New Guineans are closely linked to other Asian populations. They share a common ancestor from the same African event that other non-African groups also raised.

The findings are published in the journal Nature Communications.

Papua New Guineans look significantly different from other Asian groups and share some characteristics with sub-Saharan African groups.

According to lead author Dr. Maya Mondal, the unique physical features of Papua New Guineans probably come from natural selection: “Perhaps adaptation to the tropical climate makes them look like sub-Saharan African groups, despite their genetics clearly linking to other Asian populations.

Genetic origin remains unresolved

Scientists generally agree that modern humans left Africa about 50,000 to 70,000 years ago, spreading to Europe, Asia and more. Early archaeological studies suggest that Papua New Guinean ancestors came from another previous migration (also known as the first hypothesis of Africa), taking a coastal route through India and Southeast Asia. Archaeological evidence confirms that some of the genetic ancestors of the Papuan New Guineans may have come from this first African event. This is because Oceania’s earliest human sites date back to about 50,000-60,000 years ago, and are older than the oldest places in Europe.

In recent decades, advances in DNA sequencing have tested this first African hypothesis. However, maternal (mitochondrial) and paternal (Y-chromosome) DNA studies do not recognize any clear evidence that the main ancestors of Papua New Guineans came from previous migration. Instead, the analysis suggests that lineages connect to other non-African populations. Still, we cannot rule out traces of ancient migration from Africa’s first population.

Interestingly, the Papua New Guinea genome has a significant proportion of Denisovan DNA, a ghostly relative of Neanderthals. This unique inheritance may have arisen from mixing with Denisovan from Southeast Asia or Oceania, another factor confirming the complexity of Papua New Guinea ancestors.

Despite this study, the genetic origins of the Papuan New Guineans remain unresolved. Did Papua New Guineans split up before Europeans and Asians? Or are similar populations contributing to the genome? Did they carry the first enigmatic ancestors from the African population? Or are they part of the same family tree as other Asians who live close by?

Unique demographic history

In this study, scientists compared different demographic scenarios for the origins of genetic diversity among Papuan New Guineans using high-quality genomic data and AI-driven models. Their results suggest that the Papua New Guineans are sister groups of other Asians. The initial African contribution may not be necessary to explain its origins.

Researchers found that Papuan New Guinean ancestors had passed a dramatic population bottleneck. Perhaps most numbers fell sharply after reaching Papua New Guinea, and stayed low for thousands of years. Unlike other non-African groups, they did not experience the agriculturally-led population boom that formed Europe and Asia. This unique demographic history left a genetic signature that could, if misunderstood, be seen as evidence of contributions from unknown populations.