Genetic origins of multiple sclerosis and various diseases unveiled through analysis of ancient DNA.
Scientists have successfully compiled the most extensive repository of ancient DNA by analyzing bones and teeth from nearly 5,000 individuals who inhabited Western Europe and parts of Central Asia spanning from 34,000 years ago to the medieval era. This unprecedented database, created through a five-year project led by a team of 175 international experts, integrates previously known ancient genomes with freshly sequenced DNA extracted from hundreds of skeletal specimens obtained from museums and institutions across Europe. As a result, the project has established the world’s largest ancient gene bank.
The comprehensive analysis of this unique genetic information has revealed intriguing insights. The data suggests that genes once believed to safeguard prehistoric hunter-gatherers or Bronze Age herders from pathogens may now elevate the susceptibility to neurodegenerative diseases, such as multiple sclerosis and Alzheimer’s, in present-day Europeans. The meticulous examination of genetic changes over time, influenced by migration patterns and interbreeding, sheds light on how specific alterations in the environment favored certain genetic variants, particularly during shifts from hunter-gatherer lifestyles to farming.
The project’s initial findings, published in four papers in the scientific journal Nature, illustrate the capacity of the database to trace the historical spread of genes and diseases. Professor Rasmus Nielsen, a geneticist at the University of California, Berkeley, emphasized the significance of the dataset, stating that it enables a detailed understanding of past genetic variants influenced by natural selection.
A significant discovery from the research involves the correlation between the genetic risk of multiple sclerosis and the proportion of ancestry from ancient pastoralists, specifically the Yamnaya group, who introduced domesticated animals to Europe approximately 5,000 years ago. These nomadic herders, originating from the Pontic steppe, carried genetic variants believed to have evolved to protect against pathogens transmitted by domesticated animals. The study posits that these variants, beneficial during the transition from hunting and gathering to farming, may contribute to the higher prevalence of multiple sclerosis in present-day northern Europeans due to the Yamnaya’s migration patterns.
Furthermore, the research delves into the genetic origins of Alzheimer’s disease, associating the APOE ε4 variant with early hunter-gatherer populations in prehistoric Europe. The ancient genetic information also provides insights into the evolutionary history of traits such as height and lactose tolerance.
In response to the findings, coauthor Astrid Iversen of the University of Oxford highlighted the diminished utility of the protective benefits conferred by these genetic variants in the modern era, given substantial lifestyle changes in terms of hygiene, diet, and medical treatments.
While the database represents a significant advancement in understanding the genetic history of the region, caution is urged by experts, including Professor Tony Capra of the University of California, San Francisco. Capra emphasized the complexity of genetic influences on health, acknowledging the role of environmental factors and the cumulative impact of multiple genetic variants in traits such as multiple sclerosis. Ultimately, the research underscores the importance of extending such studies beyond Europe to gain a more comprehensive understanding of autoimmune disease risks influenced by diverse population histories.
