Ancient DNA Studies Reveal New Insights into Human Migration

Biochemical evidence suggests Norse people may have settled in Iceland nearly seventy years earlier than the historically accepted timeline of the 870s. The study led by Eske Willerslev from the University of Copenhagen examined environmental DNA, or eDNA, from sediment cores at Lake Tjornin in central Reykjavik, an area known for early human habitation.

Researchers employed radiocarbon dating and plutonium isotope analysis to create a timeline from around AD 200 to modern times. They identified a significant marker, the Landnam tephra layer, which corresponds to a volcanic eruption around AD 877.

Most evidence of human occupation in Iceland is found above this layer, suggesting that prior human activity occurred below it. The evidence indicates that human presence may have begun around AD 810, a date considered early for Viking expansion in the North Atlantic.

This conclusion stems from an increase in levoglucosan, a compound linked to biomass burning, alongside a rise in sewage-associated viruses. Critics, however, express caution regarding the conclusiveness of this early dating, with some questioning the lack of sustained evidence for continuous human activity until much later.

The eDNA findings also revealed that the arrival of settlers coincided with an increase in local biodiversity, indicating they brought livestock and cultivated crops such as barley. Contrary to previous beliefs about rampant deforestation, pollen analysis showed an expansion of birch and willow trees during the settlement period, suggesting intentional management of the landscape.

The report posits that significant biodiversity loss did not occur until after 1200, aligning with the onset of the Little Ice Age and not with early Norse settlement. This research reshapes the narrative surrounding Iceland's early settlers, emphasizing a more gradual environmental impact than previously thought.

Overall, the study highlights the potential of ancient DNA in reconstructing human history and migration patterns, offering critical insights into our understanding of ancestry and settlement dynamics in Iceland.