For 15 years, scientists have puzzled over the results of genetic tests from European bison remains that date back to the last ice age. The DNA found in the bones and teeth of many animals contain sections of genome from an unknown bovine species, reports Jessica Boddy at Science. Researchers dubbed the creature “Higgs Bison,” a play on the Higgs Boson, the “God Particle” that eluded detection by physicists for almost 50 years.
But now, cave art and further DNA testing have finally unraveled the origins of Higgs Bison, which turns out to be a previously undescribed hybrid animal. The research appears in the journal Nature Communications.
The mystery first emerged when Alan Cooper, researcher at the Australian Centre for Ancient DNA at the University of Adelaide, and his team began sequencing DNA from ancient European bison to study past impacts of climate change, writes Eva Botkin-Kowacki at The Christian Science Monitor.
“When we started extracting DNA from these bones we found a good chunk of them had a very different genetic signal to anything that anyone had ever seen before,” Cooper tells Botkin-Kowacki. “It looked like a new species, which we thought was quite odd.”
The researchers dubbed the creature Bison-X and Higgs Bison. Further examination of the DNA showed that this new animal was actually a hybrid between the steppe bison and the aurochs, a species of wild cattle believed to be the ancestor of modern cows. Beyond that the researchers knew very little about the animal, including what it looked like.
Cooper contacted French cave researchers to see if the animal might have been captured by the hunters who decorated the caves of Lascaux and Pergouset. And indeed, there was a record of this hybrid creature. Boddy reports that the depictions dating from 18,000 to 22,000 years ago are clearly images of steppe bison with their long horns and stout forequarters. But images dated from 5,000 years later show an animal without the barrel chest and with thinner horns. The cave art researchers always believed that the differences were just regional variations in cave painting styles, reports Botkin-Kowacki.
This shift in the dominant bison types was likely due to climatic changes. Cooper and his colleagues traced the Higgs Bison back over 120,000 years using DNA from fossil bison bones collected in Europe, the Urals and Caucasus Mountains, according to a press release. During warm periods, the steppe bison was the dominant bovine in western Eurasia. During cold spells, the fossil record suggests that the hybrid animals did better. While the steppe bison eventually went extinct, Higgs Bison survived and is the ancient ancestor of modern European bison.
“Once formed, the new hybrid species seems to have successfully carved out a niche on the landscape, and kept to itself genetically,” Cooper says in the press release. “It dominated during colder tundra-like periods, without warm summers, and was the largest European species to survive the megafaunal extinctions.”
One reason the genome of Higgs Bison looked so different from the European Bison is because that species went through a genetic bottleneck in the 1920s when the population was down to just 12 animals. Changes over time and the limited amount of genetic variation means the modern bison genome looks very different from its ancient ancestor.