Scientists study a rapidly adapting breed of horses – The horse


Horses have lived in Siberia since the end of the Pleistocene. Modern equine populations in the region would therefore have had to evolve over thousands of years to easily withstand this arctic climate, right? Actually no.

An international group of scientists has learned that today’s local Yakutian horse, known for its ability to withstand temperatures below -70 ° C (-94 ° F), has only arrived in the extreme -est of Siberia between the 13th and 15th centuries. This means that in just 800 years, the species has shown one of the fastest evolutionary adaptations known to large mammals.

The original Yakutian horse was still alive around 5,000 years ago, around the same time the mammoths went extinct, said Ludovic Orlando, PhD, head of the Paleomix group and curator of the cryobank at the Center de geogenetics of the Natural History Museum of Denmark, which is part of the University. of Copenhagen.

The current Yakutian horse has been imported from Mongolia over the past few millennia and has no genetic connection to the original old breed, which was likely extinct by the time the new one entered the region, Orlando said. As such, the new Yakutian could not have benefited from 30,000 years of adaptive evolution, as previously suspected. On the contrary, it has become resistant to extremely cold temperatures in record time.

“It’s really amazing, because it implies that all of the traits currently seen in Yakutian horses are the product of very rapid adaptation processes, which take place in about 800 years,” Orlando said. “This represents a hundred generations for horses. This shows how fast evolution can go when the selective pressures for survival are as strong as in the extreme environment of Yakutia. “

In their multinational study, Orlando and his fellow researchers sequenced the complete genomes of nine modern Yakutian horses, an early 19th-century Yakutian horse fossil, and a Yakutian horse fossil from about 5,200 years ago. Then, they compared these results to the genomes of Upper Pleistocene horses, modern domesticated horses, and modern Przewalski horses.

In less than a thousand years, the modern Yakutian horse has undergone significant mutations affecting hair development, body size, and metabolic and hormonal signaling pathways, the researchers said. Interestingly, they added, some of them affect the same genes that scientists have shown to be affected in humans and woolly mammoths when faced with extreme cold adaptation.

The modern Yakutian horse, stocky in stature with a thick mane and thick coat, is less than 15 hands tall and can live outdoors year round. Its presence is essential to the livelihoods and culture of the Yakutian people.

The research team participating in this genomic study included 40 scientists from Denmark, United Kingdom, United States, Spain, Russia, Switzerland, France, Finland and Saudi Arabia.

The study, “Tracking the Origins of Yakutian Horses and the Genetic Basis for Their Rapid Adaptation to Subarctic Environments,” was published in the Proceedings of the National Academy of Sciences of the United States of America.

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