Horses were first domesticated in Russia around 4,200 years ago, DNA study reveals – ABC News

Intwo weeks'time, Australia will stop for a few minutes to watch the winner of the Melbourne Cup gallop into history.

But the story of the horses in this race begins long before the powerful steedsspring out of the barriers.

The genes of these sleek thoroughbreds can be traced back 4,200 years to the grasslands between the Volga and Don Rivers in Russia.

This is where and when the ancestors of all modern horses, from flighty thoroughbreds to stocky workhorses, were first domesticated, according to a new study that claims tofinally settle a longstanding mystery.

Within just a few centuries, thesehorses had spread right acrossAsia and Europe, said the study's lead author Ludovic Orlando, director of the Centre for Anthrobiology and Genomics of Toulouse.

"This is one of those historical turning points that we identify," Professor Orlando said.

"It's the moment when the world became modern to some extent for the first time."

The study, which was published in the journalNature,suggests genes that made these animalsmore docile and robust gave them the leg-up in the evolutionary race.

Paired with later innovations such as spoked-wheelchariots, they helped shapehuman civilisation.

Professor Orlando has spent the past decade trying to pinpoint just where and whenhorses were first domesticated.

It was oncethought thattoday's horses rose from a group that was domesticated for their meat and milk by Botai herdersfurther to the east in Kazakhstan, around 5,500 years ago.

But a previous study by Professor Orlando and colleagues establishedthese horses, even though they were likely to be domesticated, were not related to modern horses.

Instead, they were genetically similar toPrzewalski'shorse, a different speciesor subspecies of horsethat has been reintroduced into Mongolia, where it runs wild.

"The Botaihorses did not give rise to the present-day genetic variation present in horses today," Professor Orlando said.

"It was clear we needed something else to start looking at this old archaeologicaldebate."

So the 160-strong team decided to map the genomes and date fossils from allof the different groups of horses known to have existed in Eurasia between 50,000 BC and 200 BC.

They gathered remains from 273 ancient horses from locationsincluding Siberia, Iberia, Anatolia and the steppes of Western Eurasia and Central Asia, and compared these with the modern horse genome.

They identified four separate groups of horses.

Theearliest ancestorsof the modern horse came from Siberia, but the closest genetic match to horses we know today came from the lowerDon-Volga region, north of the Black and Caspian Seas.

"The region we nail down is pretty narrow, about 500 kilometres [in area]," Professor Orlando said.

Within a few centuries, the genetic imprint hadstarted to appear in Anatolia and Kazakhstan, and by 3,500 years ago they were everywhere.

"It goes really fast, it almost takes place overnight."

But this is more than a story about the movement ofhorse genes.

Around 5,000 years ago, there was a mass migrationof nomadic herders known as the Yamnaya from the Western Steppes westinto Europe.

The archaeological and DNA recordshowsthese big-boned people brought with themnew languages and contributed up to 30 per cent of the genetic heritage of people in Europe today, said study co-author Morten Allentoftof Curtin University.

"One of the main speculations was thathorse domesticationfacilitated the movements of these humans," Professor Allentoft said.

Although the Yamnaya took horses with them, possibly as meat and milk, genetic mapping in the study reveals theywere not the ancestors of domesticated horses today.

"This is not the lineage we know today because it wasn't optimised for carrying people," Professor Allentoft said.

Instead, the spread of the horse as we know it appears to be aligned with the later movement east into Asia by another civilisation known as the Sintashta.

"This is a warrior culture that has a very advanced weapon industry," Professor Allentoft said.

The genetic evidence shows theSintashta bred huge numbers of horses that were suitable for riding over long distances and going into battle.

Sweeps of the genomes reveal changes in two regions that are still present in modern-day horses.

One is the mutation of a genecalled GSDMC, which is associated with narrowing of nerve canals in the spinal vertebrae, back pain, and difficulty walking in humans.

The other is the mutation ofa gene called ZFPMI, which is associated with anxiety in other animals such as mice.

A few centuriesafter theSintashtatamed their horses, they developed a new weapon: the spoked-wheel chariot.

These vehicles were much lighter and faster than solid wheel carts used by other civilisations such as the Yamnaya.

With superior horses and chariots, the Sintashta conquered Central Asia,resulting in an almost complete turnover of human and horse genetics in this region.

Valued for their chestnut-coloured coats, endurance and temperament, the lineage of horses first bred on the Western Steppesalso became a commodity and status symbolin Europe and in the Levant.

"They reachedall parts of Europe, even the northernmost parts, then replacedthe local breeds because they were much better adapted," Professor Allentoft said.

By the late Bronze Age around 1500 BC to 1000 BC, the horseshad replaced all the local populations, the study found.

Claire Wade, an animal geneticist at the University of Sydney, said the series of dates revealed by the genetics presented in the paper was very convincing.

"The overwhelming evidence in this paper suggested that domesticated horses came from the Western Steppes area," she said.

Professor Wade, who led a team that sequenced the modern horse genome in 2009, said piecing the history of evolution together using genetics provided a clearer picture thanusing archaeological records alone.

"A lot of presumed theory has been based on archaeological findings but the thing with genetics is that [genes]kind of don't lie," she said.

"99.9 per centof the time [DNA] is highly accurate and when you work in genomics, you really see how evolution works every day."

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Through a process known as genetic drift, new mutations comealong, and processes such as selective breeding can make mutations disappear.

"Now they know who the ancestor was they've been able to step back in time in that ancestral lineage and compare [the four groups] andidentifythe genes that have changed most along that gradient."

The question is whether or not the two genes identified were really instrumental in the taming of the horse, and if they are now fixed in modern horses.

"In my experience, things rarely get absolutely or utterly fixed," Professor Wade said.

"There arestill those wild genes or those old genes that float around in the population at lowfrequencies.

"So it might be interesting to see if those genes drift away in brumbies, to see if the reverse can happen."

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Horses were first domesticated in Russia around 4,200 years ago, DNA study reveals - ABC News