It’s widely accepted that continental Sahul, the combined landmass of Australia, New Guinea and Tasmania, was settled very early in human history. But the exact entry point and timing of ancient human migration into Sahul, which was eventually split by rising sea levels, is a question that has plagued paleoanthropologists. That is until now. And unexpectedly it’s a virus called hepatitis B providing the scientists with some key answers. Yuen et...