COPENHAGEN, DENMARK—According to a Science Magazine report, a new genetic study of horses, spanning a total of 42,000 years, has identified two new horse lineages, and suggests that speed in domestic horses has only been valued over the past 1,500 years. Prior to this study, Przewalski’s horse and the domestic horse were the only known horse lineages. Ludovic Orlando of the French National Center for Scientific Research, the University of Toulouse, and the University of Copenhagen, and an international team of archaeologists, geneticists, and evolutionary biologists analyzed the genomes of 279 horses whose remains were uncovered at various archaeological sites across Eurasia. One of the now-extinct lineages the researchers identified lived in the Iberian Peninsula, and the other lived in Siberia. Both were still alive between 4,000 and 4,500 years ago, Orlando said. The scientists also detected a shift in the genetic makeup of horses living in Europe and Central Asia between the seventh and ninth centuries A.D. The change could be related to Islamic expansion, Orlando explained, and the spread of popular traits carried by so-called Arabian horses. The researchers also detected a steep decline in overall genetic diversity in domestic horses over the past 200 to 300 years, perhaps due to the rise of the concept of “purebred” animals. To read more about ancient horses, go to "The Story of the Horse."