Archaeology and genetics can’t yet agree on when humans first arrived in the Americas

By | December 23, 2022

Jennifer Raff writes:

The debate over how people first arrived in the Western Hemisphere continues to roil archaeology in the United States – and to capture public attention. Today, the scientific community is contending with significant amounts of new genetic and archaeological data, and it can be overwhelming and even contradictory. These data are coming from new archaeological excavations but also from the application of newly developed tools to re-analyse prior sites and artefacts. They’re coming from newly sequenced genomes from ancient peoples and their contemporary descendants, but also from re-analysis of prior sequence data using new modelling tools. The generation of new data at times feels as though it’s outpacing efforts to integrate it into coherent and testable models.

Did humans first populate the Americas 100,000 years ago, 30,000 years ago, 15,000 years ago, or 13,000 years ago? Did they come by boat or by an overland route? Were the ancestors of Native Americans from one population or several? The answers to these questions would help us understand the grand story of human evolution. We know that the Americas were the last continents that anatomically modern Homo sapiens – humans like us – entered, but we don’t know exactly how this happened. These long-ago movements give us hints about the challenges ancient peoples across the world had to contend with during the Last Glacial Maximum (LGM), a prolonged period of coldness and aridity, when animals, plants and humans retreated to environmental ‘refugia’ for several thousand years. How did we survive this Ice Age? What technological and biological adaptations arose as the result of these environmental conditions? These questions capture the popular imagination and challenge the scientists working to uncover the details of individual lives thousands of years in the past.

To their Indigenous descendants, the stories we tell about these First Peoples of the Americas are highly relevant for additional reasons. Their deep ties and claims to the lands have often been ignored or expunged by governments, media and corporations across North and South America in order to make room for narratives that are more palatable, exciting or convenient to certain non-Native groups. The historical exclusion of Indigenous peoples from making decisions about research on their own ancestors and lands has caused significant harms to Native communities and individuals; when Native scientists and community members are full participants in the research process, the stories that emerge are not only more respectful but also more accurate. [Continue reading…]

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