As horse owners, we cherish the bond with our equine companions, but have you ever wondered what made horses suitable for riding in the first place? A groundbreaking study published in Science just over a week ago, entitled “Selection at the GSDMC locus in horses and its implications for human mobility”, led by researchers like Xuexue Liu and Ludovic Orlando from France’s Centre for Anthropobiology and Genomics of Toulouse, sheds light on this. They analysed DNA from hundreds of ancient horse remains, tracking changes in 266 key genetic spots linked to traits such as behaviour, body shape, and movement. To test one gene’s effects, they even modified it in mice.
What did they find?
Around 4,700 to 4,200 years ago, during early domestication on the Eurasian steppes, a strong genetic selection occurred at the GSDMC locus. This gene, present in all mammals, influences spine structure, strength, and coordination. In horses, a variant surged in popularity, becoming nearly universal in modern breeds (the DOM2 lineage). Mice with altered GSDMC showed straighter spines, stronger limbs, and better locomotion—traits that likely made ancient horses more resilient to riders’ weight and demands. Horses carrying this mutation even produced 20% more offspring, accelerating its spread.
What does this mean for us today?
For horse owners today, this means our animals’ rideability stems from ancient breeding for durability. The GSDMC gene ties into back health; mutations are linked to chronic pain in humans and may be related to back issues in your horse, like stiffness or reluctance to work. This research highlights how selective breeding shaped equine evolution, enabling horses to revolutionise human mobility through faster travel, warfare, and farming. It reminds us to prioritise ethical breeding and veterinary care to honour that legacy.
Xuexue Liu et al. (2025) Selection at the GSDMC locus in horses and its implications for human mobility. Science389, 925-930(2025). DOI:10.1126/science.adp4581
