New genetic research suggests that people first domesticated horses 6,000 years ago on the territory that is now Ukraine, southeast Russia and western Kazakhstan.
Once domesticated animals continued to interbreed with wild mares, they spread across Europe and Asia suggest researchers who published their work in the PNAS journal.
A study conducted at Cambridge University brought together two competing theories about how horses were domesticated.
To this date, this issue has caused heated debate among naturalists.
Archaeological evidence suggests that horses were domesticated in the western part of the Eurasian steppe. Experts believe that animals were used for riding and as a source of meat and milk.
However, the archaeological findings - such as traces of horse milk, found in ancient pots in the western Eurasian steppe– are not consistent with data obtained from mitochondrial DNA. According to the data, domestication took place in many regions of Europe and Asia.
The authors of the new study examined DNA samples from the nuclei of cells taken in 300 live horses from eight countries in Europe and Asia.
The genetic data were processed by computer models created to describe variousdomestication scenarios.
Dr Vera Warmuth from the Department of Zoology at Cambridgesays: "This suggests that the domestication of horses originated in the western plains and with the spread of domestication there was much cross-breeding with wildhorses."
The theory also explains why the data on mitochondrial DNA - containing only the genes inherited from the mother - suggests that the domestication of horses occurred many times in different places.
In fact, according to researchers, people used wild mares to increase the number of already domesticated horses because they most surely multiplied poorly in captivity.
That is what they do with the Przewalski horses - the closest wild relatives of modern horses.