Ancient DNA and MS Risks: The Yamnaya Connection

For decades, scientists have puzzled over why Multiple Sclerosis (MS) is so prevalent in Northern Europe compared to the rest of the world. A groundbreaking 2024 study published in the journal Nature has finally provided an answer. The genetic variants that increase the risk of MS today were actually survival tools gifted to us by ancient sheep and cattle herders from the Bronze Age.

The Mystery of the North-South Divide

Neurologists have long observed a distinct “latitude gradient” regarding Multiple Sclerosis in Europe. If you live in Scandinavia or the United Kingdom, your risk of developing MS is roughly twice as high as someone living in Southern Europe. For years, theories ranged from Vitamin D deficiency due to low sunlight to differences in diet.

While environmental factors matter, the genetic component remained elusive until researchers analyzed the DNA of nearly 5,000 ancient humans. They discovered that the genetic risk for MS closely tracks the migration path of the Yamnaya people.

Who Were the Yamnaya?

Around 5,000 years ago, during the Bronze Age, a massive migration occurred. The Yamnaya were a group of pastoralists (herders) who moved from the Pontic-Caspian Steppe. This region covers parts of modern-day Ukraine, southwest Russia, and western Kazakhstan.

The Yamnaya were not subtle migrants. They moved westward into Northern Europe on horseback and wagons, rapidly replacing existing populations. In some areas, such as modern-day Denmark, the Yamnaya and their immediate descendants eventually contributed up to 90% of the genetic makeup of the population. However, their genetic influence faded as they moved further south, which aligns perfectly with modern MS rates.

The Evolutionary Trade-Off

Why would evolution favor genes that cause a debilitating autoimmune disease? The answer lies in the environment of the Bronze Age.

When the Yamnaya moved into Europe, they brought large herds of domesticated animals, including sheep and cattle. Living in close quarters with livestock exposed these ancient people to a barrage of zoonotic pathogens—diseases that jump from animals to humans.

To survive, the Yamnaya needed a hyper-active immune system. The specific genetic variants identified by researchers at the University of Cambridge and the University of Copenhagen functioned as a biological shield. They boosted the immune system’s ability to attack parasites and bacteria instantly.

From Protection to Autoimmunity

In the harsh environment of 3000 BC, an aggressive immune system was a necessity for survival. In the cleaner, modern environment of 2024, that same aggressive system can become a liability.

MS is an autoimmune disease where the body attacks its own insulation (the myelin sheath) around nerve fibers. The study suggests that the “survival genes” inherited from the Yamnaya are still operating at full capacity, but without the parasites to fight, they sometimes turn their fire on the body itself.

Details of the Landmark Study

This discovery was not a small-scale observation. It resulted from a massive collaborative effort involving the Lundbeck Foundation GeoGenetics Centre and the UK Biobank.

Key Facts from the Research:

• The Database: Researchers compared ancient DNA from approximately 1,664 skeletons (dating from the Mesolithic to the Bronze Age) against genetic data from over 400,000 modern individuals in the UK Biobank.
• The Findings: They found that genetic variants associated with MS risk were virtually non-existent in earlier European populations (like the Anatolian farmers). These variants arrived specifically with the Steppe pastoralists.
• The Researcher: William Barrie, a geneticist at the University of Cambridge and co-author of the paper, noted that this finally explains the “genetic gradient” that has confused scientists for decades.

Beyond MS: Other Yamnaya Traits

The genetic legacy of the Yamnaya extends beyond immune system function. The same massive dataset revealed other traits that modern Northern Europeans inherited from these Steppe herders.

Height and Build The Yamnaya were genetically predisposed to be taller than the Neolithic farmers they replaced. This genetic influence is a major reason why populations in the Netherlands and Scandinavia are among the tallest in the world today.

Metabolism and Diet The study also highlighted genetic adaptations regarding diet. As herders, the Yamnaya had a diet rich in dairy and meat. This lineage contributed to the ability of Northern Europeans to digest lactose into adulthood (lactase persistence), although this adaptation solidified largely during the subsequent periods.

What This Means for Patients

Understanding that MS has roots in ancient disease protection changes the narrative of the condition. It is not a genetic “mistake” or a random mutation. Instead, it is the result of a highly successful evolutionary strategy that saved ancestors from extinction during the Bronze Age.

Dr. Eske Willerslev, who led the broader project, emphasized that this knowledge helps destigmatize the disease. Furthermore, knowing the specific evolutionary pathway of these genes could help pharmaceutical companies like Biogen or Novartis target treatments more effectively. Instead of broadly suppressing the immune system, future therapies might specifically target the pathways evolved to fight ancient parasites.

Frequently Asked Questions

Is Multiple Sclerosis purely genetic? No. While the Yamnaya genes increase susceptibility, MS is triggered by a combination of genetics and environmental factors. Leading theories on triggers include the Epstein-Barr virus (EBV), smoking, and low Vitamin D levels.

Can I find out if I have Yamnaya ancestry? Yes. Many commercial DNA testing services, such as 23andMe or AncestryDNA, provide breakdowns of ancient heritage. They often label this component as “Steppe,” “Eastern European,” or specifically reference the Yamnaya culture in their advanced reports.

Did the Yamnaya migrate to Southern Europe? They did, but their genetic impact was much smaller there. Southern Europe retained a higher percentage of DNA from earlier groups, such as the Anatolian farmers. This lower concentration of Steppe DNA correlates directly with the lower incidence of MS in countries like Italy and Spain.

Are there other diseases linked to these genes? Yes. The same aggressive immune response that risks MS is also linked to a higher risk of other autoimmune conditions, such as rheumatoid arthritis. However, these genes also provide stronger protection against certain infectious diseases.