New DNA analysis reveals that ancient humans used two routes to reach Australia around 60,000 years ago.
The question of when humans first arrived in Australia is very controversial among archaeologists. There are those who cite dates between around 45 and 50,000 years ago; while others suggest that the southern landmass may have been populated as early as 65,000 years ago.
A new study, last week in Science Advancespresented another theory.
After analyzing 2,500 sets of mitochondrial DNA from indigenous peoples of Australia, New Guinea, Oceania and Southeast Asia, the new study adds further support for an earlier arrival date, also revealing that It wasn’t just a single trip, but two..
As explained by , Sahul was a land mass that existed during the Pleistocene epoch, made up of what we now call Australia, Tasmania and New Guinea, which were all connected by land until about 9,000 years ago, when sea levels rose at the end of the last ice age.
The research team analyzed DNA mutation rates and genetic links between contemporary and ancient human populations to track the passages walked – or navigated – through rafts – so remarkably early in human history.
The researchers also compared this genetic information with archaeological evidence and climate data.
They turned left… and right
The conclusion of the study is that people followed two routes from the ancient Sunda land mass to reach Sahul.
Some traveled through Malaysia, Java and Timor, entering Sahul west of the site of the present city of Darwin. Researchers refer to these as “lineages of the southern route”.
However, a separate stream of genes, which researchers call “lineages of the northern route”can be traced along the island chain that runs from the Philippines and Sulawesi to Papua New Guinea, reaching Sahul through the northern tip of present-day Queensland.
Map showing the Sunda, Sahul and Western Pacific continental shelves. Orange arrows represent southern migratory routes; blue arrows represent northern migratory routes.
“We dated both dispersions for approximately the same time – about 60,000 years ago. This supports the so-called long chronology for settlement, as opposed to the so-called short chronology, which suggests settlement around 45,000 to 50,000 years ago”, the leader of the investigation explained to . Martin Richards.
The team estimates that around 36% of these first-wave lineages are from people who arrived in Australia via the northern route, while 64% descend from ancestors who took the southern route.
