When these Nomadic herders, who rode horses and used wagons, migrated across Europe and Asia around 5,000 years ago, they mated with other people. Scientists have long been aware the Yamnaya people left a strong genetic mark on Europeans and Asians. Still, the impact of the encounters between these ancient cultures has been a matter of speculation.

Northern Europe has the highest prevalence of multiple sclerosis in the world. A new study has found the genes that significantly increase a person’s risk of developing multiple sclerosis (MS) were introduced into north-western Europe around 5,000 years ago by sheep and cattle herders migrating from the east.

In a study published in Nature, a team of international researchers explains they created the world’s largest ancient human gene bank by analyzing the bones and teeth of almost 5,000 humans who lived across Western Europe and Asia up to 34,000 years ago.

By sequencing ancient human DNA and comparing it to modern-day samples, the international team of experts mapped the historical spread of genes – and diseases – over time as populations migrated.

“By analyzing the DNA of ancient human bones and teeth found at documented locations across Eurasia, researchers traced the geographical spread of MS from its origins on the Pontic Steppe (a region spanning parts of what are now Ukraine, South-West Russia, and the West Kazakhstan Region),” the study informs.

Scientists discovered the genetic variants ᴀssociated with a risk of developing MS ‘traveled’ with the Yamnaya people – livestock herders who migrated over the Pontic Steppe into North-Western Europe.

These genetic variants provided a survival advantage to the Yamnaya people, most likely by protecting them from catching infections from their sheep and cattle. But they also increased the risk of developing MS.

“It must have been a distinct advantage for the Yamnaya people to carry the MS risk genes, even after arriving in Europe, despite the fact that these genes undeniably increased their risk of developing MS,” said Professor Eske Willerslev, jointly at the Universities of Cambridge and Copenhagen and a Fellow of St John’s College, an expert in the analysis of ancient DNA and Director of the project.

“These results change our view of the causes of multiple sclerosis and have implications for the way it is treated,” he added.

The age of specimens ranges from the Mesolithic and Neolithic through the Bronze Age, Iron Age, and Viking period into the Middle Ages. The oldest genome in the data set is from an individual who lived approximately 34,000 years ago.

The findings explain the ‘North-South Gradient,’ in which there are around twice as many modern-day cases of MS in northern Europe than in southern Europe, which has long been a mystery to researchers.

From a genetic perspective, the Yamnaya people are thought to be the ancestors of the present-day inhabitants of much of North-Western Europe. Their genetic influence on today’s population of southern Europe is much weaker.

In this study scientists found:

• The startling origins of neurodegenerative diseases including multiple sclerosis.
• Why northern Europeans today are taller than people from southern Europe.
• How major migration around 5,000 years ago introduced risk genes into the population in north-western Europe – leaving a legacy of higher rates of MS today.
• Carrying the MS gene was an advantage at the time as it protected ancient farmers from catching infectious diseases from their sheep and cattle.
• Genes known to increase the risk of diseases such as Alzheimer’s and type 2 diabetes were traced back to hunter-gatherers.
• Future analysis is hoped to reveal more about the genetic markers of autism, ADHD, schizophrenia, bipolar disorder, and depression.

The study was published in Nature

Written by Jan Bartek – AncientPages.com Staff Writer

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