The discovery of a complete frozen horse in the permafrost of the Yukon in Canada, close to the Alaskan border has allowed scientists to uncover something of a secret history of the species which have a far deeper historical presence than scientists have previously supposed.

The body of the ancient horse was discovered in the course of an archaeological dig in the Thistle Creek region of the Yukon’s Klondike gold mines. The fossil of the horse had been preserved in the thick permafrost of the region which means that the DNA of the animal had been kept in very cold and very dry conditions which meant that it had not disintegrated to the extent that most animal bodies do immediately after death.

A team of scientists, working under Ludovic Orlando, an evolutionary geneticist with the Natural History Museum of Denmark at the University of Copenhagen, used a new combination of techniques to sequence the horse’s genome and date its body. They found that the animal was 700,000 years old making it significantly older than any creature to have had its genome sequence before.

The team found the task of determining the gene sequence of the animal enormously difficult because of the infiltration of bacteria into the fossil which made up the bulk of the DNA that they were able to extract. The scientists said that for every 200 molecules of DNA extracted from the fossil, only one was actually derived from the horse.

This painstaking and frustrating work ultimately paid off as the scientists were able to determine that the Equus lineage (which includes modern horses and similar animals such as zebras and donkeys) came into being approximately 4 – 4.5 million years ago. This is around 2 million years earlier than scientists previously thought.