by Christa Lesté-Lasserre
From TheHorse.com
Using paleontology, archeology, and genomics, a group of European researchers has tackled the long-debated issue of early horse domestication. According to this research team, the horse-human domestic relationship began in the grasslands of modern-day Eastern Europe, around Ukraine and Kazakhstan, and domestic herds often benefited from the addition of new, wild mares.
Despite suggestions indicating horses might have been domesticated at as many as 17 different sites worldwide, this new study points to one centralized area of domestication, said study author Vera Warmuth, PhD, researcher in the department of zoology at the University of Cambridge in the U.K. The discrepancy can be explained by a variation in the definition of domestication, she said.
“If you define every capture event of a wild female as a ‘domestication event,’ then horses were domesticated multiple times,” she explained. “However, I think there is an absolutely crucial difference between the initial establishment of a domestic founder population and incorporation of wild females into already domestic stock.”
In essence, Warmuth’s theory–based on genomic sampling of more than 300 modern horses throughout northern Eurasia and backed by fossil readings and archaeological finds–is that one group of humans began domesticating horses in the western Eurasian steppe, a grassy plains area of the Europe-Asian continent. This domestic herd spread among humans in other areas who then incorporated additional females from local wild herds.
While science reveals humans usually restocked the gene pool of most domesticated animals with wild males, they treated horses differently, Warmuth said. This might have been because wild stallions were difficult to handle, and it was simply easier to bring in new females than males.
In her study Warmuth sampled 300 modern horses (work horses in rural regions of no specific breed or origin) for genotyping.
Horses of specific breeds or lineages–especially sport horses and racehorses–would not suitable samples because their genes would likely result from modern, deliberate breeding from international sources and would not provide an accurate historical picture, Warmuth said. As a result, the team sampled no horses in Western Europe. However, researchers believe Western Europe was not likely to be involved in horse domestication, as by that time it had become thick with forest–not a very horse-friendly environment. There would have been few wild horses to capture and domesticate, she said.
Warmuth acknowledges that a second, independent domestication site might nonetheless exist in the Iberian Peninsula–modern-day Spain and Portugal. However, her study could not confirm that.
Warmuth did not include other regions of the world in the study because previous reliable research has ruled those out as likely sites of domestication or wild horse existence,
“Our study model points to a very realistic site of original horse domestication in the western Eurasian steppe,” Warmuth said. “Cattle, sheep, goats, and pigs were domesticated west of the steppes, and people with knowledge of domestic animals therefore came from the west. Also, the climate in the inner Asian steppes is much harsher than that in the western steppes. At the time of horse domestication there were likely still mainly hunter-gatherers in the eastern steppes.”
The study, “Reconstructing the origin and spread of horse domestication in the Eurasian steppe,” appeared in May in the Proceedings of the National Academy of Sciences. The abstract can be viewed by clicking HERE.