KU Genomic Research Places First Humans in Americas No Earlier Than 21,000 Years Ago

Genomic research places the arrival of the first humans in the Americas at no earlier than 21,000 years ago, right at the height of the last glacial maximum. University of Kansas researchers outlined three migration models based on a collection of relevant papers and datasets, concluding that populations living in Siberia or Beringia split into different groups during the ice age and potentially again roughly 16,000 years ago, Gizmodo reported.

Genomic Synthesis Aligns with Archaeological Evidence

The timeline produced by the genomic synthesis matches existing physical artifacts recovered from the field. David Kilby, an archaeologist at Texas State University uninvolved in the new work, told Gizmodo that the paper serves as an excellent example of how archaeology and genomics work together to answer questions about when the ancestors of contemporary Native Americans arrived.

The results of this genomic synthesis align closely with our most reliable archaeological evidence.

David Kilby

Over the past 16 years, scientists have published 257 whole genomes of ancient Americans, averaging more than one per month. Jesse Tune, an archaeologist at the University of Mississippi who was also uninvolved in the study, told Gizmodo that researchers have published an additional 1,204 genome-wide datasets during that same timeframe.

Complexities and Limits in Genetic Data

Geneticists still face significant limits when trying to connect ancient DNA to modern populations. Study co-authors Jennifer Raff, Savannah Hay, and Bethany Potter explained to Gizmodo in a joint response that samples from well-validated sites like White Sands in New Mexico are dated to 23,000 years ago, yet genetic data indicates those populations did not make a major contribution to modern Indigenous people.

The oldest published genome in the Americas belongs to the Anzick child, which is dated to approximately 12,800 years old. Scientists cannot determine whether the child’s genome represents earlier migratory waves, meaning any population before the 21,000-year estimate would belong to an undiscovered lineage, a near-decimated lineage, or a lineage that remains rare in modern Native Americans.

Divergent Archaeological Interpretations and Ongoing Debates

Researchers addressed three different migration models in the paper to reflect active debates over sites dated older than 13,000 years. Ben Potter, an archaeologist at the University of Alaska Fairbanks uninvolved in the study, told Gizmodo that he found the paper’s analysis of archaeological data less convincing than its review of genetic data.

Potter noted that most archaeologists he knows favor the post-glacial maximum model occurring after 16,000 to 14,000 years ago. He suggested reading the latest analysis alongside similar reviews by other researchers to gain a broader perspective on the peopling of the continent.

Research Team Seeks More Genetic Data to Resolve Questions

The geographic distribution of genetic data remains uneven, and the KU research team emphasized the need for additional data to resolve remaining questions. It remains unknown how undiscovered lineages fit into the broader migration timeline or whether future fossil discoveries will reconcile discrepancies between archaeological dates and genetic contributions to modern Indigenous groups.