The scientific community continues to seek answers regarding when and how the first humans set foot on the American continent. A new analysis of ancient DNA indicates that the ancestors of today's Indigenous peoples reached the Americas approximately 21,000 years ago, toward the end of the Last Glacial Maximum [1]. This finding suggests that the human presence on the continent possesses a more complex genetic heritage than previously assumed.
Migration Amidst the Ice Age
Researchers analyzed genetic data from populations linked to ancient groups in North Asia and Beringia. The results demonstrate that these groups diverged into distinct lineages during the harshest periods of the ice age. The genome of the Anzick-1 child, found in Montana and dating to approximately 12,800 years ago, serves as the foundation for these genetic models as the oldest sample on the continent [2]. Genetic data confirms that the ancestors of Indigenous peoples began to diversify much earlier than this date, around 21,000 years ago.
Controversial Sites and Lost Lineages
The dating highlighted in this report creates an interesting contrast with certain archaeological sites, such as White Sands in New Mexico. Although human footprints found at White Sands have been dated to approximately 23,000 years ago, an ancient genome has not yet been obtained from this population [4]. Researchers evaluate that these early groups may have gone extinct without leaving a genetic legacy to modern Indigenous peoples, or they may belong to a lineage that has not yet been sampled.
A Complex Dispersal Process
Following the initial entry into the continent, Northern and Southern Indigenous lineages diverged from each other approximately 15,000 years ago. During this process, populations moved, became isolated, and remixed over thousands of years. South America, in particular, hosted several different waves of migration across various time periods [3]. While current genetic evidence does not entirely rule out a migration older than 21,000 years ago, confirming such claims requires establishing a genetic link between older populations and modern Indigenous groups.
Sources and further reading
- [1] First Indigenous Americans reached the Americas no earlier than 21,000 years ago, study suggests | Archaeology News Online Magazine
- [2] Anthropology | Archaeology News Online Magazine
- [3] Giant armadillo fossil reveals early human presence in Argentina 21,000 years ago | Archaeology News Online Magazine
- [4] The ancestors of today's Indigenous people arrived in the Americas during the coldest part of the last ice age, study suggests | Live Science
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