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 iden