The first Americans, seen here eying mammoths at an ancient lake, descend from the Ancient North Siberians and a group of East Asians, who paired up around 20,000 to 23,000 years ago, genetic studies find. Credit: Karen Carr/National Park Service.Some 23,000 years ago, the first people walked along the muddy edge of a lake in what is now New Mexico. Their feet sank into the wet ground, leaving impressions that survived long after the lake disappeared.
Who were these people, and how did they reach North America so early?
Research thus far suggests that the ancestors of most present-day Indigenous Americans probably entered the continents between 20,000 and 14,000 years ago, during the coldest stretch of the last ice age or its aftermath. Yet the footprints at White Sands National Park appear to be thousands of years older.
The apparent discrepancy is at the heart of a longstanding archaeological mystery. But what seems increasingly clear is that story of the first Americans was considerably more complicated than a single migration across a frozen landscape. Some early pioneers made it to the Americas earlier than subsequent, more established waves that left a lasting impression; these first waves probably died off.
Fossilized human footprints at White Sands National Park in New Mexico date to around 21,000 to 23,000 years ago. Credit: National Park Service.In a new review published in Current Opinion in Genetics & Development, Bethany Potter and three colleagues at the University of Kansas examined decades of archaeological discoveries alongside the rapidly expanding record of ancient human DNA.
They compared three possibilities: humans arrived before the last great glacial advance, more than 25,000 years ago; during the glacial period, roughly 20,000 to 14,000 years ago; or after 14,000 years ago.
The genetic evidence best fits the middle scenario, although DNA cannot establish when the very first humans set foot in the Americas.
Following the Genetic Trail
For much of the 20th century, archaeologists believed that the first Americans belonged to the Clovis culture, known for distinctive stone spearpoints dating back approximately 13,500 years. According to that model, migrants crossed from Siberia into Alaska through a landmass called Beringia before traveling south through a gap between enormous ice sheets.
Three plaster casts of Clovis points; the originals were found in Connecticut in 1974. For decades, archaeologists thought that the Clovis were the first people to arrive in the Americas. Credit: Courtesy of the Yale Peabody Museum; CC-BY.But then archaeologists kept finding flints, tools, and footprints older than Clovis. The simple timeline could no longer explain how and when people first crossed into the American continents.
For their new study, the researchers counted approximately 257 published ancient whole genomes from the Americas, along with genome-wide data from 1,204 ancient individuals. By comparing these genetic records, scientists can reconstruct relationships between populations that lived thousands of years apart.
The resulting family tree stretches much further into the past than the DNA samples themselves.
Between roughly 25,000 and 20,000 years ago, ancient populations with Siberian and East Asian ancestry contributed to a population ancestral to Indigenous Americans. That population apparently spent thousands of years relatively isolated, an interval researchers call the Beringian Standstill.
Where this isolation occurred remains uncertain. Possibilities include Beringia itself and parts of northeastern Siberia.
Genetic evidence suggests that an ancestral lineage associated with today’s Blood/Blackfoot peoples diverged around 18,000 years ago. Another major branching event, approximately 15,500 years ago, separated the lineages scientists call Northern and Southern Native Americans.
The researchers favor an interpretation in which that latter split happened south of the continental ice sheets. If correct, people must have reached those regions beforehand, perhaps following a Pacific coastal route while glaciers obstructed inland travel.
But that’s somewhat speculative because genetic separation does not necessarily reveal where people lived. Populations could have diverged before entering the Americas.
Ben Potter, an archaeologist at the University of Alaska Fairbanks who was not involved in the review, told Gizmodo that he found the authors’ interpretation of archaeological evidence “less convincing” than their genetic synthesis. He noted that many archaeologists favor a later migration, approximately 16,000 to 14,000 years ago.
The People Missing from the DNA Record
The first people to arrive in the Americas may have arrived around the Last Glacial Maximum, the coldest part of the last ice age (about 26,500 to 19,000 years ago). Credit: Karen Carr/National Park Service.And then there are the footprints, which don’t fit neatly with other interpretations.
At White Sands, human tracks occur in sediments dating to approximately 23,000 to 21,000 years ago. A 2023 study in Science strengthened their dating using ancient pollen and sediment measurements. Additional independent research published in 2025 provided further support through 26 radiocarbon dates.
If people were walking through New Mexico so early, why doesn’t the genetic record clearly reveal them?
Partly because that record remains incomplete. The oldest published human genome from the Americas belongs to the Anzick child, buried in Montana approximately 12,800 years ago, more than 10,000 years after the earliest White Sands footprints.
The review suggests several possibilities. Earlier populations may have disappeared without leaving living descendants. Perhaps they survived for some generations, but their descendants haven’t yet been genetically sampled. Or they may have contributed only small amounts of ancestry to subsequent populations.
What’s increasingly clear is that there must have been multiple waves of migrations into the Americas with various degrees of success. This was very wild country and small groups of hunter-gatherers faced many dangers and challenges in order to survive.
An April 2026 study in Nature, examining 128 newly sequenced Indigenous American genomes, identified evidence of at least three distinct dispersals into South America. One additional ancestry stream spread around 9,000 years ago, while another arrived considerably later.
The new review’s authors call for more ancient DNA research developed collaboratively with Indigenous communities, archaeologists and tribal historians.
“Archaeological and genomic data can work in tandem to reveal subtle details of population history,” the authors write in their paper.
For now, the White Sands footprints establish something that no genetic family tree can show directly: people were walking across that ancient landscape. Exactly how they were related to those who came afterward remains a mystery.
