New research suggests modern domesticated horses hailed from the Caucasus region, emerging about 4,000 years ago. File Photo by Dmytro Pylypenko/Shutterstock
Oct. 20 (UPI) -- Horses were first domesticated in the northern Caucasus region, before conquering the rest of Europe and Asia within a few centuries, according to research published Wednesday by the journal Nature.
Although Eurasia was once populated by genetically distinct horse populations, a dramatic change occurred between 2000 and 2200 BC, when a horse population with single genetic profile, previously confined to the Pontic steppes in the North Caucasus, began to spread, the researchers said.
These horses, formerly confined to their native region in present-day Russia, soon replaced all the wild horse populations from the Atlantic Ocean to present-day Mongolia within a few centuries, according to the researchers.
"We knew that the time period between 4,000 to 6,000 years ago was critical but no smoking guns could ever be found," researcher and study co-author Ludovic Orlando, said in a press release.
"The genetic data also point to an explosive demography at the time ... this is when [humans] took control over the reproduction of the animal and produced them in astronomic numbers," said Orlando, a paleogeneticist the University of Toulouse III in France.
For decades, questions such as where were modern horses first domesticated and when did they conquer the rest of the world have dominated several fields of science, according to Orlando.
In addition, how the specific type of horses now seen globally came from the myriad other types of horses that once roamed the earth remained unknown, he said.
In 2017, Orlando's team focused on the region of Botai in Central Asia, which had provided the oldest archaeological evidence of domesticated horses, or those trained to perform farming tasks and serve as the primary mode of transport.
However, the DNA of these 5,500-year-old horses showed they were not the ancestors of modern domestic horses.
Meanwhile, other possible locations for initial domestication, such as Anatolia, Siberia and the Iberian Peninsula, had also proved "false," according to the researchers.
As a result, the team extended their study to the whole of Eurasia by analyzing the genomes of 273 horses that lived between 50,000 and 200 years BC.
That's when they discovered horses with the same genetic make-up as those seen in other parts of the world today, they said.
The researchers also found two striking differences between the genome of this horse and those of the populations it replaced: one is linked to more docile behavior and the second indicates a stronger backbone.
This suggests that these characteristics ensured the animals' success at a time when horse travel was becoming "global," according to Orlando.
The horses spread throughout Asia at the same time as spoke-wheeled chariots and Indo-Iranian languages, he and his colleagues said.
However, the migrations of Indo-European populations, from the steppes to Europe during the third millennium BC, could not have been based on the horse, as its domestication and population spread came later, they said.