November 8, 2011
DNA Study Sheds Light On Ancient Cave Paintings Of Horses
Ancient cave painters were realists rather than dreamers, at least when it came to depicting horses, according to an analysis of pre-historic horse DNA.
Humans began painting curious creatures -- white horses with black spots -- on the walls of European caves about 25,000 years ago.
These horses, while popular breeds today, were thought not to exist before humans domesticated the species about 5000 years ago, leading scientists to wonder how much imagination went into the drawings.
Indeed, past studies of prehistoric DNA have only produced evidence of brown and black horses during that time.
However, the current study of ancient horse DNA concludes that these spotted horses did indeed live in Europe during those times, suggesting that early artists may have been painting what they saw rather than depicting imaginary creatures.
The renowned Lascaux Cave in the Dordogne region of southwest France and the Chauvet Cave in southeast France feature plentiful scenes of brown and black horses, while other caves like the Pech Merle in southern France are feature paintings of white horses with black spots.
The current analysis, which focused on horses since they appeared most frequently on the rock walls, offers a glimpse into the environment tens of thousands of years ago.
To hone in on the genetics of equine coat color, the international research team analyzed DNA from fossilized bones and teeth from 31 prehistoric horses.
The samples were unearthed from more than a dozen archaeological sites in Siberia, Eastern Europe, Western Europe and the Iberian Peninsula.
The analysis showed that 18 of the horses were brown, seven were black, but six had a genetic variant–known as LP–that corresponds to leopardlike spotting in modern horses. Furthermore, out of 10 Western European horses estimated to be about 14,000 years old, four had the LP genetic marker, suggesting that spotted horses were not uncommon during the time the ancient cave paintings were made.
If so, prehistoric artists may have been drawing what they observed, rather than what they imagined, said the researchers concluded.
Prehistoric horses came in at least "three coat color[s]," said geneticist and lead researcher Arne Ludwig of the Leibniz Institute for Zoo and Wildlife Research in Berlin.
"Exactly these three [colors] are also seen in cave paintings,” he said.
“Cave art is more realistic than often suggested."
As for why the spotted phenotype became less common after 14,000 years ago, the researchers note that some modern horse breeds with two copies of the LP gene suffer from night blindness, which would have made ancient horses more vulnerable to predators.
The researchers also speculate that the gene variant might have been beneficial during the Ice Age, when a white spotted coat could help camouflage the creatures in snowy conditions.
The analysis was published online November 7 in the Proceedings of the National Academy of Sciences (PNAS).
Image Caption: Replica of horses and hands cave painting displayed in the Brno museum. Credit: Wikipedia
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