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, 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. The study, published in Science, 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. The study used DNA samples collected by Prof John Clegg and Prof Sir David Weatherall in the 1980s, a collection housed at the WIMM.

 
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.

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. A proportion of the samples examined came from a DNA archive housed at the WIMM that covers many of the Pacific island of Micronesia and Melanesia. The samples were collected in the 1980s by Prof John Clegg and Prof Sir David Weatherall, as part of their haemoglobinopathies studies. The collection is curated by Dr Kathryn Robson, also an author on this paper.

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