The Pacific islands were one of the last places on Earth to be inhabited by humans. Even 3,000 years ago, when the Great Pyramid of Giza had stood for 800 years, large parts of the Pacific islands were still untouched by human feet.
Ancient DNA evidence is now telling us that humans made a complex series of three epic migrations across vast open plains of crystal-clear waters in canoes. One of the strangest things about this migration is that the current inhabitants of Vanuatu speak languages rooted in Southeast Asia, yet share most of their genetic ancestry with Papua New Guinea.
Fortunately, most of this fiddly puzzle is now explained in two studies recently published in the journals Nature Ecology & Evolution and Current Biology.
The research centered around Vanuatu, a series of 80 islands that stretch 1,300 kilometers (800 miles) that are seen as the gateway to the Pacific. Researchers used a combined approach of genetics, archaeology, and linguistics to study the genomes of 19 ancient people discovered across Vanuatu, Tonga, French Polynesia, and the Solomon Islands, and then compared the data to the genetics of 27 people currently living in Vanuatu.
They found that the Lapita peoples were the first to make it to Vanuatu around 3,000 years ago. They were a seafaring Neolithic people descended from a largely East Asian genetic ancestry from current-day Taiwan and spoke a form of Austronesian language.
Just 500 years later, male settlers of almost entirely Papuan ancestry began to head over to this land too. “We found a genetically Papuan-related individual dating to around 2,500 years ago in Vanuatu, far earlier than had been previously estimated using only modern genetic data,” co-lead author Dr Cosimo Posth of the Max Planck Institute for the Science of Human History explained in a statement.
However, the two studies disagree about how this happened exactly, with the Current Biology study arguing that there was a sudden boom of migration, but the Nature paper arguing that the Papuans slowly dripped in and mixed with the population. Either way, this managed to profoundly change the genetic makeup of the Islanders. Unexpectedly though, their language remained the same. The people of Vanuatu still speak Austronesian-derived languages, just like its first settlers.
“Population replacement with language continuity is extremely rare – if not unprecedented – in human history,” co-author Professor Russell Gray said.
After this time, people then finally migrated out to the far-flung islands of Polynesia. Once again, a puzzle emerges: although these people appear to have Papuan ancestry, it seems to be from yet another source.
“There’s very clear evidence of not one, not two, but at least three big eastward migrations from the big islands in Indonesia and New Guinea,” Dr David Reich of Harvard Medical School told Nature News. “This is only the tip of the iceberg.”