Speed, smarts, and the heart of a champion: using genomic analysis, scientists have identified DNA changes that helped turn ancient horses such as those in prehistoric cave art into today's Secretariats and Black Beautys, researchers reported Monday.

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.

Once merchants, soldiers and explorers could gallop rather than just walk, it revolutionized trade, warfare, the movement of people and the transmission of ideas. It also enabled the development of continent-sized empires such as the Scythians 2,500 years ago in what is now Iran.