Did The Silk Roads Help Shape Equine Genetics?

Did The Silk Roads Help Shape Equine Genetics?

The Silk Roads paved the way for the lucrative Chinese silk trade, but they also opened the door to extensive intercultural, educational exchanges, and horse trading and breeding.

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Modern horse breeds are the product of some phenomenal mixes of horses from various regions across the globe. Geneticists know this interregional mixing occurred many centuries ago, but how do genes from a horse in Western Europe during the Biblical era become blended with horses residing in Eastern Asia?

Simple answer: The Silk Roads.

“The Silk Roads had been shown to have influenced the genetic structure of humans in eastern Eurasia, so I was curious about how far the Silk Roads played a role in horse movement as well,” said Vera Warmuth, PhD, researcher in the department of zoology at the University of Cambridge in the U.K.

The “Silk Roads” were a 4,000-mile series of connecting trade routes linking the Mediterranean Sea to southeast China starting in about 200 BC. They paved the way for the lucrative Chinese silk trade, but they also opened the door to extensive intercultural and educational exchanges. And, Warmuth said, they opened the door to horse trading.

She recently investigated the genetic material of 455 modern-day village horses (breeds not currently traded internationally) in 17 different locations near the ancient Silk Roads.

“My study shows that humans shaped the genetic structure of horses not only through selection for certain traits (speed, stamina, jumping ability, conformation, coat color, etc.), but simply through moving them around and enabling high levels of gene flow between populations that perhaps would otherwise not have been in much contact,” she said.

Mapping out horses' genetic evolution is complex business, but careful genetic studies can help scientists identify factors that play a role in that evolution, said Warmuth. In her work, she used a method known as “least cost modeling”—which doesn’t have anything to do with the price of the analysis. Rather, this analysis shows how influential different factors were in genetic development. So, for example, Warmuth found that geographical barriers along the Silk Roads—like mountains and wide rivers—affected horses' genetics. In other words, it was “costly,” both physically and financially, to the horse traders at the time to cross these barriers. So certain genes were more concentrated than others in between such barriers.

She also compared the genetic differences with those that could have resulted from trade blocks implemented by the Soviet Union, which significantly restricted international trade for most of its 70-year existence. That restriction would theoretically have applied to horse trading, Warmuth said; however, her genetic analysis shows the restriction had no effect on the village horses' makeup. “This recent trading pattern has not influenced the genetic structure of the kinds of horses I looked at,” she said.

The strongest influence on village horse genetics throughout the European and Asian locations covered by Warmuth’s research remains the Silk Roads, she said.

Previously, Warmuth and colleagues used genetic analysis to determine that horses were originally domesticated in the Western Steppes of Eurasia, near modern-day Ukraine—an area later serviced by the Silk Roads.

The study, "Ancient trade routes shaped the genetic structure of horses in eastern Eurasia," was published in Molecular Ecology

About the Author

Christa Lesté-Lasserre, MA

Christa Lesté-Lasserre is a freelance writer based in France. A native of Dallas, Texas, Lesté-Lasserre grew up riding Quarter Horses, Appaloosas, and Shetland Ponies. She holds a master’s degree in English, specializing in creative writing, from the University of Mississippi in Oxford and earned a bachelor's in journalism and creative writing with a minor in sciences from Baylor University in Waco, Texas. She currently keeps her two Trakehners at home near Paris. Follow Lesté-Lasserre on Twitter @christalestelas.

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