Ancient DNA Reveals American Horses Crossed China Before Reaching Europe

A new genetic analysis overturns the long‑standing view that early horses reached Europe solely from the continent, showing that they carried a North‑American genetic component that traveled through China before arriving in Europe. The study spotlights the extinct Dalian horse as a pivotal conduit for this intercontinental gene flow, reshaping current ideas about equid movements during the late Pleistocene.

Ancient Horse DNA Reveals a Trans‑Beringian Highway

The research, published in Proceedings of the Royal Society B: Biological Sciences, focuses on the Dalian horse, a lineage previously thought to be confined to northeastern China. By sequencing mitochondrial DNA from fossil remains, the team identified a distinctive North‑American ancestry that later appears in Siberian horse populations, indicating that the Dalian horse functioned as a genetic bridge between continents.

“Dalian horses likely served as one route through which North American-related genetic ancestry entered Northeast Eurasian horse populations,” the researchers wrote.

Fossil material from Qinggang County and Harbin supplied the mitochondrial genomes that revealed extensive gene flow across the Bering Strait, positioning the Dalian horse as a major player in the exchange of equine lineages between North America and Eurasia.

“[The] findings position the Dalian horse as a key lineage for elucidating late Pleistocene equid evolution in Northeast Asia and the dynamics of trans‑Beringian genetic exchange,” the study noted.

Wider Distribution Than Previously Thought

Earlier work limited the Dalian horse to a narrow area in northeastern China, but the new data extend its range into Yakutia and southern Siberia. The evidence suggests that the species migrated northward across China, then northwest into Siberia and northeast into Yakutia during the late Pleistocene, acting as a conduit for Eastern Beringian ancestry to enter the northeast Siberian gene pool.

“In light of spatiotemporal overlap between Dalian and northeast Siberian horses and the documented gene flow between them, our findings suggest that Dalian horses likely served as a conduit for the introduction of Eastern Beringian ancestry into the northeast Siberian gene pool,” researchers said.

This broader geographic footprint revises the narrative of horse dispersal across Eurasia, portraying the Dalian horse as a significant contributor to the genetic composition of later domestic and wild equids.

Genomic Portrait of Ancient Caballine Horses

Specialized Diet and Climate Shift Sealed Its Fate

Stable isotope measurements indicate that the Dalian horse depended on a highly specific grazing regime, limiting its capacity to cope with rapid environmental transformations. As the late Pleistocene climate cooled around 40,000 years ago, expanding wetlands and peatlands replaced the open grasslands that sustained the species, constraining food availability.

“Dalian horses’ specialised dietary niche constrained its ability to adapt to rapid late Pleistocene environmental change, ultimately contributing to its extinction,” the study said.

Combined with its large body size and limited ecological flexibility, these factors led to the disappearance of the Dalian horse, mirroring the decline of other megaherbivores such as North American horses and giant camels at the end of the Pleistocene.