Using genomic analysis, scientists have identified DNA changes that helped turn ancient horses such as those in prehistoric cave art into today's Secretariats. Understanding the genetic changes involved in equine domestication, which earlier research traced to the wind-swept steppes of Eurasia 5,500 years ago, has long been high on the wish list of evolutionary geneticists because of the important role that taming wild horses played in the development of civilization.
It was all made possible by 125 genes, according to a study in Proceedings of the National Academy of Sciences. Related to skeletal muscles, balance, coordination and cardiac strength, those genes produced traits so desirable that ancient breeders selected horses for them, said geneticist Ludovic Orlando of the Natural History Museum of Denmark, who led the study. The result was generations of horses adapted for chariotry, pulling plows and racing. Genes active in the brain also underwent selection. Variants linked to social behavior, learning, fear response and agreeableness are all more abundant in domesticated horses.
Orlando's team examined DNA from 29 horse bones discovered in the Siberian permafrost and dating from 16,000 and 43,000 years ago, and compared it with DNA from five modern domesticated breeds. Some genes in today's horses were absent altogether from the ancient ones, showing they arose from recent mutations. Among them: a short-distance "speed gene."
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