Scientists unwrap mystery of world's first explorers
An international team of scientists has discovered that Aboriginal Australians descend directly from an early human expansion into Asia that materialised 70 000 years ago. This occurred at least 24 000 years before the population movements that led to today's Europeans and Asians. The results, published in the journal Science, shed new light on the prehistory of our species and offer a first-time look at the human genome from an Aboriginal Australian.
Researchers from Australia, Canada, China, Denmark, Estonia, France, Germany, Japan, Mexico, the Netherlands, Switzerland, the United Kingdom and the United States sequenced the genome to show that modern-day Aboriginal Australians are the direct descendents of the first people who arrived in the land down under as early as 50 000 years ago.
For the purposes of their study, the researchers used a lock of hair donated to a British anthropologist by an Aboriginal man from the Goldfields region of Western Australia in the early 20th century. The researchers isolated deoxyribonucleic acid (DNA) from this hair to investigate the genetics of the first Australians and to elucidate how humans first dispersed across the globe.
Based on their genome assessment, which showed no genetic input from modern European Australians, the ancestors of the Aboriginal man split from the ancestors of other human populations around 64 000 to 75 000 years ago. So Aboriginal Australians are the direct descendants of the earliest modern explorers, that is, people who migrated into Asia before settling in Australia about 50 000 years ago.
The results of the study help substantiate how Aboriginal Australians are the population with the longest association with the land they call home today. The Goldfields Land and Sea Council, the organisation that represents the Aboriginal traditional owners for the region, fully endorsed this study.
'Aboriginal Australians descend from the first human explorers,' study leader Professor Eske Willerslev of the University of Copenhagen explains. 'While the ancestors of Europeans and Asians were sitting somewhere in Africa or the Middle East, yet to explore their world further, the ancestors of Aboriginal Australians spread rapidly, the first modern humans traversing unknown territory in Asia and finally crossing the sea into Australia. It was a truly amazing journey that must have demanded exceptional survival skills and bravery.'
According to the researchers, the findings have wide implications for helping us better understand how our human ancestors travelled across the globe. To date, the only ancient human genomes have been obtained from hair preserved under frozen conditions. Despite using hair that was preserved in much less ideal conditions, the researchers were able to perform genome sequencing without the risk of modern human contamination that commonly occurs in ancient bones and teeth.
They point out that through analysis of museum collections, and in collaboration with descendent groups, the genetic history of many indigenous populations around the globe can be studied, including groups that have recently moved about or intermingled.