2024-01-14 16:04:33
The recent analysis of nearly 5,000 remains by an international research group resulted in the world’s largest ancient human DNA gene bank. The research covered a wide time scale, specimens were examined from the Mesolithic to the Middle Ages, the oldest genome dates back to approximately 34,000 years.
The research team reported that they were able to identify several neurodegenerative diseases, including the source of multiple sclerosis (MS), and they also got answers to how these diseases reached Europe and other parts of the world. Multiple sclerosis is the most widespread in Northern Europe and has been puzzling scientists for years.
What is Multiple Sclerosis?
It is a chronic nervous system disease that is associated with damage to nerve cells and inflammatory processes in the nervous system. MS affects the central nervous system (brain and spinal cord) and can cause different symptoms.
Its main characteristic is the inflammatory foci or plaques that form around nerve cells, which damage the myelin sheath of nerve cells. Myelin is the protective layer around nerve cells that is responsible for the efficient conduction of nerve impulses. In patients with MS, myelin is damaged or destroyed due to inflammatory processes, which hinders the smooth transmission of nerve impulses.
When myelin is damaged, this transmission can be disrupted or blocked, leading to various, often severe, symptoms. Autoimmune attack on myelin leads to inflammation and damage, and in severe cases, scar tissue forms, which further impedes the transmission of nerve signals. The disease is currently incurable.
Recent research has revealed that key genetic factors that increase the risk of multiple sclerosis were introduced to northwestern Europe regarding 5,000 years ago. This genetic influx is attributed to the migration of sheep and cattle farmers from the east.
It was found out where the disease originated from
The research team carried out a detailed analysis of ancient human remains – bones and teeth – unearthed from various locations in Eurasia. The researchers linked the origin of MS-related genes to the Pontic steppe, a vast region that includes parts of present-day Ukraine, southwestern Russia, and western Kazakhstan. The study identified the Yamnaya people, ancient livestock breeders known for their extensive migrations, as carriers of these genetic variants.
Interestingly, these genetic traits gave the Yamnayas a survival advantage, possibly protecting them from infections caused by their livestock. However, the same genes also increased the risk of developing multiple sclerosis.
“Carrying MS risk genes may have been a significant advantage for the Yamnaya when they arrived in Europe, despite the fact that they also brought with them an increased risk of the disease in question,” explained Professor Eske Willerslev, from the University of Cambridge and the University of Copenhagen. Willerslev, an expert in ancient DNA analysis and the leader of the project, notes that these results will not only transform our understanding of MS, but will also be of crucial importance in the treatment of the disease.
This comprehensive study offers an explanation for the ‘north-south gradient’, the observed phenomenon of a higher incidence of multiple sclerosis in Northern Europe than in Southern Europe.
From a genetic point of view, the Yamnaya can be considered the ancestors of many people in today’s Northwest Europe, while their influence is less pronounced in the population of Southern Europe. Previous studies have identified 233 genetic variants associated with increased MS risk. These variants, influenced by environmental and lifestyle factors, increase the risk of developing the disease by approximately 30%. The new research found that these genetic risk factors for MS already existed in ancient human remains, bridging the link spanning thousands of years.
The gene bank available to researchers can be useful for the research of several serious diseases
This collection of DNA research has also led the group to a better understanding of several other diseases affecting humans. According to these studies, the gene bank was instrumental in linking genes from ancient populations to modern diseases such as Alzheimer’s disease and type 2 diabetes. The team also hopes that with this much DNA, it will be possible to more thoroughly investigate the underlying genetic markers of diseases such as autism, ADHD, schizophrenia, bipolar disorder and depression.
Co-author of the study, Dr William Barrie, a postdoctoral researcher in the Department of Zoology at the University of Cambridge, expressed the team’s astonishment at the results.
“These findings represent a significant advance in understanding the evolution of MS and other autoimmune diseases” Barrie said one statementban.
“They underscore the profound impact of our ancestors’ lifestyles on our susceptibility to disease today, reminding us that we inherited our immune systems from our ancestors” he declared.
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