New Genetic Study Reveals Arrival Routes of First Australians

A new genetic study reveals that modern humans arrived in Australia approximately 60,000 years ago, utilizing two distinct migration routes. Utilizing a dataset of nearly 2,500 genomes, researchers were able to substantiate the so-called 'long chronology' of human arrival in Sahul, contrary to previous genetic models suggesting a much later arrival of 47,000 to 51,000 years ago.

The research, published in Science Advances, indicates that one group of early humans arrived from southern Sunda, encompassing the Indonesian islands, while another group migrated from northern Sunda, which includes the Philippines, as stated by Martin Richards, an archaeogeneticist at the University of Huddersfield and co-author of the study.

These early settlers are believed to have shared a common ancestry that dates back to the migration out of Africa approximately 70,000 to 80,000 years ago before diverging during their journey through Southeast Asia.

The analysis of mitochondrial DNA, which is inherited through the maternal line, and Y-chromosome data, which follows the paternal line, supported the conclusion that the two groups settled in northern Australia around the same time, around 60,000 years ago, as highlighted by Richards.

Additionally, the research suggests that these early humans likely interbred with archaic human species, including Homo floresiensis, or 'hobbits', although the extent of this interaction remains unclear.

Helen Farr, an archaeologist at the University of Southampton and study co-author, emphasizes the significance of these findings for Indigenous communities in Australia, noting that many Aboriginal Australians believe they have always resided in their ancestral lands.

The data corroborates their deep heritage, suggesting a continuous connection to the land and sea for at least 60,000 years. The study represents a pivotal moment in bridging the gap between genetic and archaeological evidence, which has historically shown discrepancies regarding the timing of human arrival in Australia, according to Christopher Clarkson, an archaeologist at Griffith University.

He noted that previous genetic research often relied on molecular clock techniques that aligned with the 'short chronology', whereas this new study employed a correction curve to account for the mutation rates in the analysed population.

Clarkson described the findings as a satisfying consolidation of evidence that aligns genetic data with archaeological records, suggesting that the debate over the timeline of human arrival in Australia is far from settled.

Bastien Llamas, an evolutionary geneticist at the University of Adelaide, acknowledged the impressive correlation between genetics and archaeology but cautioned that further research and ancient DNA analysis from key remains are necessary to definitively resolve the timing of these migrations.

The team plans to continue their research, analyzing hundreds of whole human genome sequences to further test and refine their results, aiming to provide a clearer understanding of the migration patterns of the first Australians.