New research challenges the long-held belief placing Anatolia, in modern day Turkey, as the birthplace of domesticated horses.
It is now thought that they were likely brought to the region during the Bronze Age, in about 2000 BCE. Researchers now suggest that the Black Sea region is the more likely candidate as the habitat in which horses were first domesticated.
The exact location in which horse domestication took place, however, remains unknown, according to a recent paper published in the Science Advances magazine.
The domestication of horses has had deep implications for human history, allowing homo sapiens to move faster and over longer distances. This was important for the spread of culture and languages, as well as for trade and warfare.
Eva-Maria Geigl, Head of Research at France’s L’Institut Jacques Monod, and her team tested the horse domestication hypothesis through the paleo-genetic analysis of 111 equine remains from 14 archaeological sites across Anatolia and the southern Caucasus. The tests covered a time-period of between 9000 to 500 BCE, including the presumed point at which the domestication of horses took place.
“We discovered that around 2000 BCE, a genetic turnover took place in horses from Anatolia and Transcaucasia, as horses prior to 2000 BCE were carriers of four different maternal (mitochondrial) lineages, three of which seem to be unique to this area and one of which is now extinct,” Geigl said, “Afterwards we observed a strong increase of different mitochondrial lineages known from other areas and also in present-day horses.”
Along with the explosion of maternal lineages after 2000 BCE, researchers also observed a strong increase in coat colours. These are considered markers of domestic horses, while horses prior to this date had the typical wild-type coat colour.
Taken together, these results clearly indicate that domestic horses were introduced into Transcaucasia and Anatolia around 2000 BCE, and that they had not been domesticated locally in this area.
Since DNA in archaeological bone samples in southwest Asia is mostly poorly preserved, the researchers designed a paleo-genetic method combining the power and specificity of a targeted PCR (polymerase chain reaction) approach with the efficiency of the high throughput next-generation sequencing methods. The power of this method allowed the team to collect data from 60 remains.
The study also yielded the most ancient genomic evidence for a human-made hybrid, a mule, which is a cross between a female horse and a male donkey, from an Early Iron Age context dated to 1100 to 800 BCE.
As a result, Iron-Age Anatolians, such as the Hittites, produced sterile hybrids, which are a technically and financially challenging endeavour. Being the most expensive species mentioned on a livestock price list dating to the Hittite period, mules were obviously highly valued.
“I am stunned by the massive and fast introduction of domestic horses in this area, which also convinced me that horses must have been domesticated elsewhere,” Geigl said. “For me, the most likely hypothesis is that this happened in the Pontic-Caspian Steppes where people lived at this time who used domestic horses, the wheel and chariots, as well as bronze objects and weapons.”