Revealing the Genetic Origins: Unveiling Ancient DNA's Link to Multiple Sclerosis and Beyond
New insights into multiple sclerosis and other diseases emerge as ancient DNA from European bones offers a window into the genetic origins of these debilitating conditions
Get the latest science news and discoveries by signing up for CNN's Wonder Theory science newsletter. Delve into the universe with updates on groundbreaking discoveries and scientific progress. A comprehensive database of ancient DNA, derived from the bones and teeth of nearly 5,000 humans spanning from 34,000 years ago to medieval times, has been compiled by scientists. This extensive database covers individuals from Western Europe and parts of Central Asia.
The detailed pool of ancient genetic information suggests that genes which may have protected prehistoric hunter-gatherers and Bronze Age herders from pathogens could now increase the risk of neurodegenerative diseases like multiple sclerosis and Alzheimer's in Europeans. The ambitious five-year project, involving 175 international experts, combined previously known ancient genomes with freshly sequenced DNA from hundreds of skeletal specimens from museums and institutions across Europe. The scientists involved claim that this data forms the world's largest ancient gene bank.
A Neanderthal male in his twenties is being examined by a Natural History Museum employee in London. The model is part of the museum's 'Britain: One Million Years of the Human Story' exhibition, which is scheduled to run from February 13th to September 28th, 2014. (Photo by Will Oliver/PA Images via Getty Images)
Will Oliver/PA Images/Getty Images
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The database was utilized by researchers to track the migration and interbreeding of populations over time, mapping the spread of genes and diseases. This revealed how environmental changes, such as the transition from a hunter-gatherer lifestyle to farming, favored specific genetic variants. Comparing ancient DNA with modern-day samples provided new insight into debilitating disorders and physical traits in present-day populations. The initial findings of the project were published in four papers in the scientific journal Nature on Wednesday.
Rasmus Nielsen, a professor of integrative biology and geneticist at the University of California, Berkeley, who helped spearhead the project, highlighted the significance of the dataset, stating, "What's remarkable about this dataset is that now we can actually see what happened in the past, we can actually see what are the genetic variants that change in frequency in the past due to natural selection. And that allows us this very, very fine-grained picture," during a news briefing this week.
The researchers sequenced DNA from human remains in museum collections around Europe.
The Danish National Museum
The initial research findings, which analyzed over 1,600 genomes, revealed a connection between Bronze Age herders and multiple sclerosis (MS). MS is a lifelong autoimmune disease of the nervous system that impacts approximately 2.5 million individuals globally. This complex condition is influenced by various environmental and genetic factors and can result in a range of symptoms such as vision problems, impaired arm and leg movement, sensory issues, and balance difficulties.
Northern Europeans have a higher susceptibility to the disease, according to the study, although the specific reasons for this remain poorly understood.
Using the database, researchers delved into the genetic roots of multiple sclerosis. What they discovered was that the risk of developing the condition is linked to the extent of ancestry from an ancient group of pastoralists who brought domesticated animals to Europe roughly 5,000 years ago.
The Yamnaya, nomadic herders of cattle and sheep, were the first horse riders and originated from the Pontic steppe, which extends from southeastern Europe into Kazakhstan. As they migrated westward into Europe, they carried specific genetic variants evolved to protect them against pathogens from domesticated animals, according to researchers.
The genetic variations may have been advantageous for European populations as they transitioned from hunting and gathering to farming. Additionally, the team concluded that the increased presence of ancestral pastoralists in present-day northern Europeans could contribute to the higher prevalence of the disease in that region, as the Yamnaya people primarily settled in northern Europe.
University of Chicago
"We were all amazed by these findings, which represent a major advancement in our knowledge of the progression of MS and other autoimmune diseases," stated William Barrie, a postdoctoral researcher in the University of Cambridge's department of zoology and coauthor of one of the papers. "Demonstrating the impact of our ancestors' lifestyles on modern disease risk emphasizes the extent to which we have inherited ancient immune systems in a contemporary world."
Coauthor Astrid Iversen, a professor of virology and immunology at the University of Oxford, pointed out that the protective benefits of these genetic variants are no longer as effective in today's world. "Our modern lifestyle, including hygiene, diet, and medical advancements, along with our evolutionary history, may make us more vulnerable to certain diseases, such as autoimmune diseases like MS, compared to our ancestors," Iversen stated.
Researchers have also traced the roots of a genetic variation, APOE ε4, which is associated with a higher risk of developing Alzheimer's disease. One of the four studies discovered that this gene can be traced back to early hunter-gatherer communities in prehistoric Europe.
Barrie mentioned that DNA from hunter-gatherers is more prevalent in Northeastern Europe, indicating a heightened genetic susceptibility to developing Alzheimer's disease in the region. In addition, the ancient genetic data provides insight into the evolutionary history of characteristics such as height and lactose tolerance.
In the accompanying commentary for the study, Samira Asgari, an assistant professor in genetics and genomic sciences at the Icahn School of Medicine at Mount Sinai in New York, emphasized the importance of expanding these studies beyond Europe to other regions in order to gain a better understanding of how variations in population history may have influenced the susceptibility to autoimmune diseases such as multiple sclerosis.
A man photographed a statue of the iceman named Oetzi, discovered in 1991 in the Italian Schnal Valley glacier, as it was displayed at the Archaeological Museum of Bolzano on February 28, 2011. The statue was presented during an official event showcasing the reconstruction. Dutch experts Alfons and Adrie Kennis used three-dimensional images of the mummy's skeleton and the latest forensic technology to create a new model of the living Oetzi. The photograph is credited to Andrea Solero/AFP/Getty Images.
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"While human biology is universal, every population has its own distinct history. By focusing solely on one population, we may miss out on valuable discoveries that could significantly contribute to the advancement of medicine," Asgari wrote in a statement regarding the four studies, in which he was not directly involved.
Tony Capra, an associate professor of epidemiology and biostatistics at the University of California, San Francisco's Bakar Computational Health Sciences Institute, stated that the new database offers the most comprehensive views of the genetic history of a region to date. He added that this has allowed the authors to fill in missing details in our understanding of the inhabitants and the influence of natural selection on the traits of modern individuals.
Capra warned that there is rarely a straightforward explanation for why one population may possess a genetic variant while another does not. "The evolutionary history of our species has significantly influenced our current health and traits," explained Capra in an email, although he was not directly involved in the research.
"Nevertheless, both in the past and present, the impact of genetic effects is influenced by the environment. In the case of MS and most other traits, genetic effects are the outcome of various genetic variants," he explained. "In conclusion, we cannot definitively trace the origins of MS to Bronze Age populations, but the movements and environments of these populations have contributed to the variations in MS risk that we observe today."
