Introduction
Ancient DNA analysis has provided new insights into why people of northern European ancestry have a higher risk of developing multiple sclerosis (MS). Researchers have discovered that this increased risk is a result of genetic variants carried by a group of ancient herders known as the Yamnaya, who migrated into northwestern Europe approximately 5,000 years ago. These genetic variants not only increased the risk of MS but also likely provided protection against infections carried by their cattle and sheep. This groundbreaking research sheds light on the link between ancient migrations, genetic variations, and the prevalence of MS in different populations.
Ancient DNA Unravels the Story
By studying ancient human DNA extracted from teeth and bones, scientists were able to track the migration patterns of the Yamnaya people and identify disease-linked genes. The Yamnaya, originating from modern-day Ukraine and Russia, brought these gene variants with them as they moved into northwestern Europe. Surprisingly, these variants not only persisted within the population but also flourished, suggesting that they provided some kind of advantage to the Yamnaya herders. The study, published in the journal Nature, is part of an extensive project that aims to explore the genetic history of early humans in Europe and western Asia.
Genetic Variants and MS
The focus on MS in this study was driven by the fact that the disease is most prevalent among individuals of northern European descent, particularly those with white ancestry. MS occurs when the immune system mistakenly attacks the protective coating on nerve fibers, causing a range of symptoms that can vary from person to person. While the exact cause of MS is still unknown, it is believed that certain infections may trigger the condition in individuals who are genetically susceptible. To date, more than 230 genetic variants have been identified that can increase the risk of developing MS.
The Link to Northern Europe
The researchers compared ancient DNA samples with present-day individuals from a gene bank in the UK, focusing on populations in the north to track the persistence of MS-linked genetic variations. The analysis revealed that the genetic variants associated with MS were more prevalent in the north, aligning with the direction of the Yamnaya migration. In Denmark, for example, the Yamnaya quickly replaced the ancient farmers, making them the closest ancestors of modern Danes. Scandinavian countries, where MS rates are particularly high, also showed a strong correlation with the presence of these genetic variants.
Exploring the Connection
The question remains: why do gene variants that once strengthened ancient immunity now play a role in an autoimmune disease like MS? The researchers speculate that differences in exposure to animal germs between ancient and modern humans may have disrupted the balance of the immune system, leading to autoimmune conditions. However, further research is still needed to confirm this link.
Unlocking the MS Divide
This groundbreaking study finally provides an explanation for the north-south divide in MS prevalence across Europe. However, genetic experts urge caution and emphasize the need for additional research to validate these findings. The ancient DNA analysis has opened up new avenues for understanding the complex interplay between genetics, ancient migrations, and the development of diseases. By delving into our genetic past, researchers are uncovering the intricate threads that connect us to our ancestors and shed light on the health challenges we face today.
Source: F5mag.com