Ever wonder how horses became so crucial to human civilization? Well, we made them that way, according to a new study in the research journal Animal Genetics. Researcher Lars Andersson and his team have discovered that one gene -- affectionately known as "the gait keeper" -- is responsible for controlling a horse's gait, which encompasses a range of motion including walking, trotting, and galloping. Following this initial discovery, Andersson noticed that some horse breeds also have an additional gait -- called the ambling gait -- which produces a smooth ride that is desirable to humans.
"The ambling gait is smooth because the horse always has one foot on the ground, but the horse never flies in the air like when they trot or gallop," Andersson said. "When the horse flies in the air, a human needs more experience to ride because he or she is moving vertically up and down. But the smooth ride is much easier, especially over long distances."
Because the mutation affects the way neurons are configured in the horses' spinal cords, he explained, horses with the mutation contract their limbs differently than horses without. "Think about how humans move," Andersson said. "If you go for a walk, you can see how you swing your arms in harmony with how you move your legs, because programming in your spinal cord tells you how to move to get a balanced walk. The same thing is happening with the horse, and it allows the horses to move at different gaits."
He and his team studied a sample of over 4,000 horses from around the world, and they found that the vast majority of them contained the genetic mutation for ambling. Andersson suspects it's because humans have practiced "positive selection" for this trait for hundreds of years, because they realized how useful the smooth ride could be for a variety of needs, from transportation to warfare. As people came to recognize and rely on the ambling gait, they actively bred, traded, and sold horses that exhibited it.
"We found the trait in horses from Japan, where samurai preferred it because of their heavy armor, and we suspect Genghis Khan used them during his conquest," Andersson said. "Humans spread them throughout Asia, then Europe, and then the conquistadors brought them to Latin and North America -- they were useful all over the world. Humans realized they were a key advantage in building civilizations."
Horse Gait Slow Motion