Scientists See Spots on Prehistoric Horses

Scientists See Spots on Prehistoric Horses

"During the Ice Age, Eurasia was a snow steppe habitat (like the steppe region in North America during winter today)," researcher Arne Ludwig, PhD, explained. "A white horse with dark spots was well adapted on this environment."


According to a group of international genome researchers, one population of prehistoric Eurasian horses were either black, bay, or leopard-spotted bay and white. And given their Ice Age climate, those rock-and-snow-looking coats might have been ancient horses' best camouflage.

Consistent with 25,000-year-old cave drawings, genetic sampling of ancient horse bones confirm that horses carried genes for black, bay, or leopard-spotted coats, said Arne Ludwig, PhD, of the Leibniz-Institute for Zoo and Wildlife Research and the Research Group for Evolutionary Genetics, in Berlin, Germany.

By examining the DNA of 31 horses that lived between 15,000 and 20,000 years ago in modern-day Siberia and Europe, Ludwig found six of the sampled horses had spotted coats (18 were bay and seven were black). Ludwig said this marks the first time horse fossils have been tested for the leopard spotting gene--known by scientists as the "LP allele," which North American researchers identified in 2010.

These prehistoric Appaloosa-like horses could have had a considerable evolutionary advantage in the snowy, rocky steppes where they lived, Ludwig said. But that's only true if they were "heterozygotes," the term the researchers used to describe horses that possessed the kind of LP allele mutation that causes visible colored spots on a white background. The other kind of LP allele mutation, referred to as "homozygote" by the team, causes a white background without any colored spots.

"Heterozygotes were probably positively selected depending on camouflage," Ludwig said. "During the Ice Age, Eurasia was a snow steppe habitat (like the steppe region in North America during winter today). A white horse with dark spots was well adapted on this environment. This selective advantage of the coat color phenotype was responsible for the high frequency of the LP allele in the Eurasian horse population."

Homozygotes, on the other hand, would not have been so lucky. Definitively associated with night blindness, homozygous LP alleles would certainly have made white horses that blend in well with the snow, but they would have been easy targets for predators from dusk till dawn. Ludwig said none of the ancient horses in his study were considered homozygotes.

All of the spotted horses were bay and white, Ludwig said. Study results identified no evidence of black or sorrel spotted horses or any sorrel horses at all. Furthermore, none of the samples in this study or his similarly structured study completed in 2008 were positive for the tobiano or sabino gene mutations, which cause "paint" coat patterns, he said.

The ancient bones used in the study are preserved in European archeology collections, institutes, and university departments. Approximately one to five grams of bone or tooth was necessary for the DNA testing each horse.

The study, "Genotypes of predomestic horses match phenotypes painted in Paleolithic works of cave art," appeared in November 2011 in the Proceedings of the National Academy of Science. The abstract can be viewed online.

About the Author

Christa Lesté-Lasserre, MA

Christa Lesté-Lasserre is a freelance writer based in France. A native of Dallas, Texas, Lesté-Lasserre grew up riding Quarter Horses, Appaloosas, and Shetland Ponies. She holds a master’s degree in English, specializing in creative writing, from the University of Mississippi in Oxford and earned a bachelor's in journalism and creative writing with a minor in sciences from Baylor University in Waco, Texas. She currently keeps her two Trakehners at home near Paris. Follow Lesté-Lasserre on Twitter @christalestelas.

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