The Polynesian exploration of sparse islands of the Pacific will remain humanity’s greatest migration until we head for other planets. And it clearly wasn’t just a one-way trip; evidence indicates that trade networks covering thousands of kilometers were maintained for centuries. Now, a new study of ancient Polynesian DNA has indicated that it wasn’t just trade goods that were exchanged. DNA from at least two different sources ended up spreading through the population of Polynesia before European contact.

The study also suggests that our understanding of how history produced the genetics of modern Polynesians was completely off-base.

That understanding was built by looking at the DNA of modern Polynesians and comparing it with the genetics of other peoples around the Pacific. The data indicated that modern Polynesians have a mixed ancestry, with the majority of their genomes coming from an East Asian population. An additional contribution, however, came from the Papuans that inhabit the islands north of Australia.