New research shows Prehistoric hunter-gatherers were the first people to ride horses and explores its impact on migration and languages

University of Exeter

Source - http://www.exeter.ac.uk/news/research/title_657899_en.html

The excavation in Botai 2015 yielded one of the few human skeletons to have been retrieved from this site of the first hunter-herders that domesticated the horse

A new study has discovered that horses were first domesticated by hunter-gatherer descendants in Kazakhstan who left no direct modern trace.

The domestication of the horse was one of the most important milestones in human history because it allowed people and their languages to move further and faster than ever before and it led to widespread farming and horse-powered war.

Academics from around the world collaborated on the new inter-disciplinary research which was published today in two papers in the journals Science and Nature (Wednesday, May 9 2018).

Professor Eske Willerslev, who holds positions both at St John’s College, University of Cambridge, and the University of Copenhagen, jointly led the studies which looked at archaeological findings, history, and linguistics. The academics analysed ancient and modern DNA samples from humans and compared the results, the 74 ancient whole-genome sequences studied by the group were up to 11,000 years old and were from inner Asia and Turkey. The research sheds new light on the long-standing “steppe theory” on the origin and movement of Indo-European languages made possible by the domestication of the horse.

A number of conflicting theories have been presented about who first domesticated the horse with some previous studies suggesting the pastoralist Yamnaya people, a dominant herding group of people who lived in Eastern Europe and Western Asia, were responsible for spreading the revolutionary skill. 

However, it seems the earliest domestic horses were being used by the Botai people 5,500 years ago further East in Central Asia, but these people were completely unconnected with the Yamnaya pastoralists. A further twist to the story is that Botai descendants were later pushed out from the central steppe by migrations from the west. Their horses were replaced too, indicating that horses were domesticated in other regions too.

Professor Willerslev said: “The Yamnaya were considered to be the people who first domesticated the horse because they were sheep herders that were already making use of wheeled vehicles. People had suggested that Botai people, on the other hand, needed outside influence to make such significant advance, but we find that they did it independently. It is among the most important cultural events in history because it completely transformed what we could do as humans.”

The study did not find a genetic link between the Yamnaya people and the Botai people, critical to understand the eastward movement of Yamnaya people. Apparently, the eastward Yamnaya expansion bypassed the Botai people completely, travelling 3000 kilometres across the steppe to the Altai Mountains in Central and East Asia.

It was previously discovered that the Botai people had kept horses with bit wear in their mouths and milk residue was found which showed they had been milking the horses.

Professor Alan Outram, from the Department of Archaeology at the University of Exeter, and one of the paper’s authors, said: “We now know that the people who first domesticated the horse in Central Asia were the descendants of ice age hunters, who went on to become the earliest pastoralists in the region. Despite their local innovations, these peoples were overrun and replaced by European steppe pastoralists in the middle and later Bronze Age, and their horses were replaced too.”

The authors also demonstrated the oldest known Indo-European language, Anatolian Hittite, did not result from a massive population migration from the Eurasian Steppe as previously claimed. 

By looking at various studies of Europe in the Bronze Age, the researchers offer important new insights on how population and language spread across Asia by demonstrating that the spread of language and genetic ancestry is better understood by groups of people mixing together rather than simply groups moving around the world.

Gojko Barjamovic, Senior Lecturer on Assyriology at Harvard University, explained: “In Anatolia, which was densely settled by complex urban societies, the history of language spread and genetic ancestry is better described in terms of contact and absorption than simply a movement of population.”

Dr Rui Martiniano, from the Wellcome Trust Sanger Institute in Cambridge and one of the lead authors, said: “The spread of the Indo-European languages into Europe, Northern India and Pakistan is likely to have been facilitated by the increased mobility brought by the domestication of the horse. The Yamnaya left a great genetic impact in Europe, but we now know that they had a more limited direct impact in Asia. Instead, subsequent migrations occurring around the late Bronze Age may have been responsible for the introduction of these languages in South Asia.”

By analysing the sedentary Copper Age Namazga farmer culture from what is now Turkmenistan, the authors found that while the Yamnaya expansion did not leave a traceable genetic impact in South Asia, the introduction of farming through ancient populations brought western Eurasian genetic ancestry to South Asia. 

Professor Richard Durbin, of the Department of Genetics, University of Cambridge and Wellcome Sanger Institute, who jointly led the study, commented: “Now is an extremely exciting time when the computational analysis of ancient and modern genome data is refining and revising our view of human history.”

In this study geneticists, historians, archaeologists and linguists all find common ground - pointing to increased interaction between the steppe and the Indus Valley during the Late Bronze Age as the most plausible time of entry of Indo-European languages in South Asia. Several authors of the paper had radically conflicting views before a final interpretation was achieved.

Dr Guus Kroonen, historical linguist at Leiden and Copenhagen University, added: “The recent breakthroughs in ancient genomics poses challenges for archaeologists, linguists and historians because old hypotheses on the spread of languages and cultures can now be tested against a whole new line of evidence on prehistoric mobility. As a result, we now see that geneticists are inspired by key questions from the humanities, and that research within the humanities is revitalised. In the future we will hopefully see more cross-disciplinary co-operations such as the one leading to this study.”

The Nature paper  analyses 137 ancient alongside the sequences of a lot of people living across Eurasia today. It studied the genetic connections between different historical groups of people to see how they interacted with each other. The authors traced the changes in genetic components of the inhabitants of the steppe region from the end of the Bronze Age through the Iron Age to the present day.

The authors demonstrated that the mounted Scythian Nomads of the steppe who were of European genetic origin and spoke an Indo-Iranian language were gradually mixed with East Asian Turkic- speaking people who later, under the name of Huns, nearly brought the Roman Empire to a fall when they invaded. This was followed by the Justinian plague, whose origin for the first time can be identified into Central Asia, with its spread linked to intensified contact, perhaps along the Silk Road, an ancient network of trading routes.

Professor Kristian Kristiansen, from the Department of Historical Studies, University of Gothenburg, led the second paper with Professor Willerslev. He said: “Genetically and linguistically what happened is the people living in the steppe were being gradually replaced from European ancestry to being East Asian.”

Peter de Barros Damgaard, PhD student from the Centre for GeoGenetics, Natural History Museum, University of Copenhagen and first author on the paper, explained: “We discovered that the Eurasian steppe was incredibly dynamic, an area of major transformations all the way into Medieval times. And as we moved into these more recent periods, we could also correlate our genetic data with written historical sources documenting several invasions and political replacements.

“Often these came from the East, but also forming confederations with European groups. In several cases, we would see European newcomers buried alongside Mongolian newcomers.   This was a period of major transformation and constantly shifting military confederations which is reflected in an incredible genetic heterogeneity.”

Professor Willerslev explained: “It is because of the domestication of the horse that The Silk Road, a major trading route between Europe and Asia, appeared. It was an extremely important part of the world to control in terms of taxing people. As soon as you get the mounted horse, it’s like getting a sports car on a highway.”

The domestication of the horse also allowed the Huns, a nomadic tribe, to travel all the way to Rome to invade.

Professor Kristiansen added: “They became an incredible military force that people have to protect against. The Great Wall of China was also built against Mongolia when the forerunners of the Huns were there.”