Multiple sclerosis is a legacy of nomadic steppe herders

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The origin of the degenerative disease widespread in northern Europe has been traced to the nomadic shepherd people who expanded from central Asia to Europe 5,000 years ago. Genes that predispose to multiple sclerosis were brought to the northern part of our continent by the Jamnai, steppe herders who replaced European hunter-gatherer populations in many places. In ancient times, these variants had a protective role, while today they are disadvantageous.

Four scientific articles published on reconstruct the history of this and other diseases Nature and based on the largest database of ancient DNA.

Inhomogeneous risk. Multiple sclerosis is a neurodegenerative disease in which the immune system mistakenly attacks the sheath that insulates and protects the nerve fibers of the brain and spinal cord. So far, 233 genetic variants have been identified that increase the risk of developing this pathology by approximately 30%. About twice as many cases of multiple sclerosis occur in northern European countries than those diagnosed in southern Europe, but the reasons for this difference have not yet been clear.

Heavy luggage. The genetic legacy left to Europeans by the Yamnai (or Jamna culture), horse-taming nomadic herders originating in present-day Russia and Ukraine, is much more pronounced in modern northern Europeans and less represented in present-day southern European populations, for reasons related to the places of their expansion. A team of 175 researchers from around the world, led by scientists from the universities of Cambridge, Copenhagen and California, Berkeley, has now found that genetic variants associated with the risk of multiple sclerosis “traveled” with the Yamnaya, moving from the Asian steppes to northwestern Europe.

A unique database in the world. The discovery was made possible thanks to the analysis of DNA extracted from the bones and teeth of approximately 5,000 individuals preserved in museum collections and living in Western Europe and Asia at different times (from the Mesolithic to the Neolithic to the Bronze and Iron Ages to the Viking Age), beginning 34,000 years ago. Ancient genetic profiles are part of the largest and most comprehensive database of ancient DNA, the Lundbeck Foundation’s GeoGenetics Centre. The team compared this with genetic data from around 400,000 present-day people stored in the UK Biobank, the UK’s main medical database, and found that the same genetic predisposition to multiple sclerosis was also present in individuals who lived thousands of years ago.

From useful to harmful. These genes must have been a survival advantage for the Eurasian shepherds of the time, as they protected them from infections carried by grazing animals. At the same time, they increased the risk of multiple sclerosis. A risk that has become all the more apparent in modern times, as explained by Astrid Iversen, co-author of the paper at the University of Oxford: ‚ÄúToday we have very different lives from those of our ancestors in terms of hygiene, nutrition. and the possibility of medical care. This, combined with our evolutionary history, means we may be more susceptible to certain diseases than our ancestors, including autoimmune conditions such as multiple sclerosis.”

Every nation has its own ills. The tendency of northern European populations to be higher than in southern Europe could also come from Yamnaya. While various health conditions can be traced back to the genetic influence of other ancient populations that migrated to our continent.

For example, Southern Europeans, who typically retain more of the DNA of old farmers, are genetically more prone to developing bipolar disorder, a serious psychiatric disorder. While residents of Eastern Europe have a higher genetic risk of developing Alzheimer’s disease and type 2 diabetes. In the words of William Barrie, co-author of the paper and a scientist from the University of Cambridge, “we are the inheritors of ancient immune systems in the modern world.”



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