Left: Regional crop prevalence and dates. Right: Examples of crop remains found at the site.

Strong genetic, cultural, and linguistic evidence suggests that Madagascar and the Comoros Islands were colonized by Austronesian-language-speaking people from the Southeast Asian Islands around the 7th or 8th century CE; no written or archeological evidence has yet been available to support this hypothesis, however, leaving researchers to draw conclusions about human migration without traditional "physical evidence."

Now, researchers are pointing to seeds of ancient crops as physical verification. In a new study published in PNAS, the researchers—including SFI External Professor Henry Wright—show that the abundance of Southeast Asian cultivars such as cotton, mung bean, and rice in Madagascar and the Comoros far outweighed native African crops like millet, sorghum, and cowpeas, which were prevalent in contemporaneous East African settlements. Moreover, the seeds from the East African settlements show a gradual influx of Asian crops, suggesting that they arrived via commerce, while their overwhelming abundance in Madagascar and the Comoros reflect patterns of human colonization.

While many questions remain about the order and nature of Austronesian colonization of Comoros and Madagascar, these new archeobotanical clues may help spur further insights.

Read the paper in PNAS (May 31, 2016)