New research of British scientists indicates that domestic horses originated in the steppes of modern-day Ukraine, southwest Russia and west Kazakhstan, which is supported by gene study and reconciles previous conflicting theories. For several decades scientists puzzled over the origin of domesticated horses. Based on archaeological evidence, it had long been thought that horse domestication originated in the western part of the Eurasian Steppe--Ukraine, southwest Russia and west Kazakhstan. However, the idea that horses were just tamed in this area is at odds with some results of gene analysis. There are a large number of female lineages in the domestic horse gene pool, which is commonly thought to reflect multiple domestication events across a wide geographic area. In order to solve the mystery, scientists from the University of Cambridge used a genetic database of more than 300 horses sampled from across the Eurasian Steppe to run a number of different modeling scenarios. They reported in the U.S. journal Proceedings of the National Academy of Sciences that previous theories could be reconciled. "Our research clearly shows that the original founder population of domestic horses was established in the western Eurasian Steppe," said Dr. Vera Warmuth from University of Cambridge. Then the domesticated herds were repeatedly restocked with wild horses as they spread across Eurasia. "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 invoke multiple domestication origins," Warmuth said. The research provides the first genetic evidence for a geographically restricted domestication origin of horses in the Eurasian Steppe, and shows that the tremendous female diversity is the result of later introductions of local wild mares into domestic herds, thus reconciling evidence which had previously given rise to conflicting scenarios