In previous threads some were asking about the history of the horse.
This article may help in your education about where the horse came from and when science gets done studting this there may be even more information available.
A 700,000-year-old horse bone found in the permafrost of a Yukon gold mine has yielded a complete genetic profile, breaking scientific records and revealing many new insights about the evolution of horses.
But once the task was complete, and the ancient horse's genome was compared with that of the only living wild horse species, the Przewalski's horse; modern horses; and donkeys, the team learned a lot about horse evolution. They found that the common ancestor of the species they analyzed arose around four million years ago — twice as early as previously thought. It appears the Przewalski's horse diverged from the modern domestic horse about 50,000 years ago and hasn't mixed with the domestic horse since. Over time, some parts of the genome that showed the biggest changes were the genes that control the ability to smell and the animal's immune system.