A new genetic study has uncovered previously undetected traces of Austronesian ancestry in populations along the western rim of the Indian Ocean, shedding light on a long-standing mystery about the reach of ancient seafaring migrations.
The Austronesians were a vast group of peoples who originated in what is now Taiwan and the islands of Southeast Asia, and whose descendants spread across much of the Pacific and Indian Oceans through extraordinary seafaring migrations.
Beginning around 3000–1500 BC, Austronesian-speaking peoples developed advanced ocean-going canoes and navigation techniques that allowed them to travel farther than almost any other ancient culture. Their expansion carried them south and east through the Philippines, Indonesia, and Melanesia, reaching Polynesia, Micronesia, and even New Zealand. To the west, they voyaged across the Indian Ocean to Madagascar—some 6,000 kilometres from their likely departure points in Indonesia.
While the Austronesian expansion across the Indonesian Ocean to Madagascar and the Comoros is well established, little evidence had ever been found of similar influences in East Africa or the Arabian Peninsula. To revisit this anomaly, researchers conducted genomic surveys of populations in Somalia and Yemen, comparing the results with genetic data from the Banjar people of Indonesia — the known source of the westward Austronesian dispersal.
The study revealed significant Asian genetic contributions in both maternal lineages and overall genome variation, pointing to two distinct episodes of Austronesian contact. The first dates back to the early phases of the Austronesian expansion, likely around the same time as the settlement of Madagascar. The second occurred much later, near the end of the 19th century, possibly through renewed movements from Southeast Asia.
These findings suggest that Austronesian voyages across the Indian Ocean were far more complex and prolonged than previously believed, continuing intermittently for centuries and leaving genetic traces in unexpected parts of Africa and Arabia.
