A new fossil DNA study has rewritten the evolutionary history of the horse, showing that the extinct Dalian horse of northeastern China served as a genetic bridge between North America and Eurasia.For decades, the traditional narrative held that horses were European imports to the Americas, brought by Spanish conquistadors who surprised Native Americans with a creature they had never seen. But the latest genomic research has turned that story on its head.Horses actually originated in North America millions of years ago, and they reached Europe only thanks to a surprising genetic intermediary in China.
dalian horse
According to researchers at the state’s Laboratory of Geomicrobiology and Environmental Changes, the Dalian horse, once considered a local oddity restricted to northeastern China, had a distinctly American lineage that went back to ancient horse populations in Siberia.That gene flow means that the bloodlines that later gave rise to modern European horses acquired their American roots through this Chinese interbreeding.“The Dalian horses likely served as a pathway through which genetic lineages related to North America entered northeastern Eurasian horse populations,” the researchers write in the Proceedings of the Royal Society B: Biological Sciences.
50,000 years journey
Equids originated in North America during the early Eocene. The genus Equus, which first emerged about 4 to 5 million years ago, is the only surviving lineage, which includes all modern horses, donkeys, and zebras.According to the fossil record, Equus spread from North America to Eurasia via the Bering Land Bridge about 2.6 million years ago, and then underwent extensive evolutionary diversification.A 2025 study had already established that ancient horses repeatedly migrated between North America and Eurasia during the Pleistocene era, when sea levels fell and a land bridge connected the two continents.The new study analyzed 20 Dalian horse specimens from the late Pleistocene, mostly from Heilongjiang province and Qinggang County in Harbin. The researchers retrieved the entire mitochondrial genome and identified a “distinct component” of the Eastern Beringian lineage, which was Native American DNA, which was absent from other Northeast Asian counterparts.The researchers suggested that gene flow across the Bering Land Bridge continued until 50,000 years ago, although it was “intermittent and geographically limited.”First identified from fossils in the Gulongshan Cave in Dalian, the Dalian horse is believed to have been restricted to northeastern China during the late Pleistocene. New study expands its range Two similar fossils from Yakutia in the Russian Far East fall within the mitochondrial diversity range of the Dalian horse.This suggests that the range of the Dalian horse “extends from northern China at least northwestward into southern Siberia and northeastward to Yakutia,” the researchers said.
Why did the Dalian horse disappear?
Despite its role as a genetic conduit, the Dalian horse eventually disappeared. Researchers found that its extinction was not due to a lack of genetic diversity, but due to its inability to adapt to a changing climate.Stable isotope analysis showed that the Dalian horse was an expert herder. As the environment changed around 40,000 years ago, becoming more humid, with dry grasslands replaced by peatlands and wetlands, its narrow diet left it unable to adapt.For the Dalian horse, its large body size and “limited ecological plasticity” meant that it could not survive the loss of its high-quality forage.This extinction trajectory mirrors that of other extinct large herbivores of that era, such as North American horses and giant camels.