24. May 2018

Horse domestication and hepatitis: Three articles from Eske Willerslev in Nature and Science

Head of center Eske Willerslev, from the Center for GeoGenetics, has published three scientific articles on the same day in the prestigious journals Nature and Science. The articles take their point of departure in fossil DNA and gives an insight in ancient migration along the Silk Road.

Excavation of one of the few human skeletons of the first hunter-herders that domesticated the horse.
Excavation of one of the few human skeletons of the first hunter-herders that domesticated the horse (Foto: Niobe Thompson, 2015)

May 9 was a special day for head of center Eske Willerslev and Ph.D. student Peter de Barros Damgaard from the Center for GeoGenetics. On that date, they, together with colleagues, published three scientific articles in the high-profile journals Nature and Science. The three articles are based on an analysis of fossil DNA – the genetic material within cells – made by Willerslev and his research group, which includes researchers from numerous international universities. The research team has been studying DNA material from bones and teeth that originated from humans who lived along the historic trade route known as the Silk Road. The time span covered by the research went from approximately 7,000 years ago up to today.

All three scientific articles have their point of departure in a revolutionary study from 2015. In that study, Willerslev and his research crew revealed a hitherto unknown migration that occurred 5,000 years ago during the Bronze Age, a migration that had a great impact on the European population. The study showed that early steppe-nomads, called Yamnaya, migrated to Northern Europe from today’s Caucasus. The migration changed the Northern European gene pool and culture and has played a significant role in the history of humankind up to this day.

In their work, Willerslev and his colleagues have mapped the full DNA-material – also known as the genome – in more than 200 ancient humans, which makes it the biggest genome study ever. With such a massive amount of material, the researchers can travel back in time and reconstruct history. The first article examines the genetic development up until the Yamnaya nomads migrated to Northern Europe. The second article takes the analysis a step further and investigates genetic development all the way up to the Middle Ages and the Empire of Genghis Khan around 1100 AD. The third article examines the origins of the widespread virus hepatitis B, through the study of diseases in the fossils’ DNA.

The world’s first horse domesticators

With the two first articles, Willerslev and his research team have confirmed a theory that suggests that a hunter-gatherer people from Kazakhstan, called the Botai, were the first humans to domesticate the horse on the Eurasian steppe about 5,000 years ago. This domestication later became important for the Yamnaya nomads.

“The domestication of the horse became the trigger for the Yamnayas to blossom, and suddenly we have these huge groups that invade the existing societies,”  Damgaard said to videnskab.dk.

The domestication of the horse is one of the most important milestones in human history, since it enabled an increase in human mobility and it helped to spread human language over a much wider area and faster than ever before.

Read more about the research here

Further information can be read at videnskab.dk here (in Danish)

The publication in Nature can be found here

The publication in Science can be found here

Oldest known DNA of a virus traces the origins of hepatitis B
With the study of 200 ancient skeletons, the international research group has succeeded in tracing the hepatitis B virus (HBV) back 4,500 years. It is the oldest DNA finding of a virus ever, since the previous record was a DNA virus that was approximately 400 years old.

Also, the study revealed that 10 percent of the population that lived along the Silk Road from the early Bronze Age to the Middle Ages was infected with HBV. Therefore, this discovery rejects the theory that the virus originated in America and that it came to Europe only 500 years ago.

“We can see that HBV has been in Europe for at least 4,500 years, and there is not much evidence to suggest that this virus originally came from America,” Willerslev told the Lundbeck Foundation.

The study, which was recently published in Nature, offers an important insight into the origins and development of HBV that can potentially be of benefit in developing future hepatitis vaccines.

“This study is just the beginning. We are talking about one virus here, but there are a lot of other viruses we can look at,” Professor Willerslev said to an audience at St. John’s College at Cambridge University.

Read more about the research at St. Johns College here

The publication in Nature can be found here

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