New research indicates that domestic horses originated in the steppes（大草原） of modern-day Ukraine, southwest Russia and west Kazakhstan, mixing with local wild stocks as they spread throughout Europe and Asia. The research was published 07 May, in the journal PNAS.

For several decades scientists puzzled over the origin of domesticated¹ horses. Based on archaeological evidence, it had long been thought that horse domestication² originated in the western part of the Eurasian Steppe (Ukraine, southwest Russia and west Kazakhstan); however, a single origin in a geographically⁴ restricted area appeared at odds⁵ with（差异） the large number of female lineages in the domestic horse gene⁶ pool, commonly thought to reflect multiple domestication "events" across a wide geographic³ area.

In order to solve the perplexing history of the domestic horse, scientists from the University of Cambridge used a genetic⁷ database of more than 300 horses sampled from across the Eurasian Steppe to run a number of different modelling scenarios⁸.

Their research shows that the extinct wild ancestor of domestic horses, Equus ferus, expanded out of East Asia approximately 160,000 years ago. They were also able to demonstrate that Equus ferus was domesticated in the western Eurasian Steppe, and that herds⁹ were repeatedly restocked with wild horses as they spread across Eurasia.

Dr Vera Warmuth, from the University of Cambridge's Department of Zoology¹⁰, said: "Our research clearly shows that the original founder¹¹ population of domestic horses was established in the western Eurasian Steppe, an area where the earliest archaeological evidence for domesticated horses has been found. The spread of horse domestication differed from that of many other domestic animal species, in that spreading herds were augmented¹² with local wild horses on an unprecedented¹³ scale. If these restocking events involved mainly wild mares, we can explain the large number of female lineages in the domestic horse gene pool without having to invoke¹⁴ multiple domestication origins."

The researchers provide the first genetic evidence for a geographically restricted domestication origin in the Eurasian Steppe, as suggested by archaeology¹⁵, and show that the tremendous female diversity is the result of later introductions of local wild mares into domestic herds, thus reconciling evidence which had previously¹⁶ given rise to conflicting scenarios.

The research was funded by the BBSRC, German Academic Exchange Service (DAAD), and the Leverhulme Trust.