New research shows that the migration of ancient people in Eurasia may have influenced the risk of various diseases in modern Europeans…
Common Diseases
The findings were published in the journal Nature. Along with two other articles by the co-authors of the study, the papers include DNA analysis from the bones and teeth of hundreds of ancient individuals, the oldest of whom date back to the Neolithic period or the Middle Stone Age. Scientists compared the DNA of these individuals with the gene pool of present-day Europeans.
The study shed light on the genetic legacy of three ancient human migrations to different regions of Europe. These include: the arrival of hunter-gatherers about 45,000 years ago; Neolithic farmers from the Middle East about 11,000 years ago; and herders of sheep and cattle from the Pontic Steppe—a region spanning Eastern Europe and Central Asia—around 5,000 years ago.
The risk variant known as ApoE4 increases the risk of developing Alzheimer’s disease but may enhance fertility in women.
The project also received collaboration from museums across Europe and Western Asia. This collaboration helped the research team create a gene bank, opening new opportunities for analyzing and understanding diseases based on ancient DNA, while also expanding to other neurological and psychiatric disorders such as Parkinson’s, Alzheimer’s, Attention Deficit Hyperactivity Disorder (ADHD), and schizophrenia. In total, researchers compared the gene pool of 1,750 ancient individuals with the gene pool of around 410,000 people contributing data to a repository known as the U.K. Biobank.
The authors estimated that these participants inherited ancient DNA. One of the new papers identified gene variants associated with autoimmune disease MS. This disease was carried by farmers from the Pontic Steppe when they primarily migrated to Northern Europe.
This may help explain why MS is most common among people of Northern European descent. The researchers concluded that these risk variants had “been positively selected.” This means they conferred some advantages to the migrants and therefore faced evolutionary pressure to persist.
Specific gene variants related to immune function are known to increase human susceptibility to MS. These include HLA gene variants, which help the body detect pathogens. However, like a double-edged sword, certain HLA variants are also closely associated with autoimmune diseases, where the body attacks its own cells.
The research authors hypothesized that in the past, these variants may have helped ancient farmers combat infectious diseases from animals. However, as human lifestyles changed over time—in terms of hygiene, diet, and medicine—these variants took on new significance.
The research team also suggested that understanding the evolutionary dynamics driving the selection of these genes could be significant for treating MS.
Dr. Lars Fugger, a senior co-author of the study and a Professor of Immunology at the University of Oxford (UK), stated: “Thinking of the double-edged sword, what we need to aim for is to attempt to recalibrate the immune response rather than completely eliminate it.”
Individuals with more DNA from the hunter-gatherer group may have a higher genetic risk of developing type 2 diabetes.
Risk Variants
In another article, the author group discovered the inheritance of risk variants for 35 complex traits. This means traits caused by the interaction of multiple genes and their interactions with the environment.
They found that genes related to lactose tolerance in adults appeared in Europe about 6,000 years ago. This phenomenon may be more prevalent among present-day Northern Europeans compared to Southern Europeans, partly because Northern Europeans inherited genes from farmers in the Pontic Steppe.
The research authors also found that individuals with more DNA from the hunter-gatherer group they studied may be at a higher genetic risk for type 2 diabetes and Alzheimer’s disease compared to those with fewer of those gene variants.
Modern populations carrying this hunter-gatherer DNA predominantly live in Eastern Europe. The risk variants for Alzheimer’s may have been positively selected. For example, a risk variant known as ApoE4 increases the risk of developing Alzheimer’s disease but may enhance fertility in women.
Dr. Astrid Iversen, a senior co-author of the study and a Professor of Virology and Immunology at the University of Oxford, noted that the increased fertility may have provided our ancestors with a “huge advantage.”
Meanwhile, Omer Gokcumen, a Professor of Evolutionary Anthropology at the University of Buffalo in New York, who did not participate in the research, stated: “These papers add evidence that diets and lifestyle changes, often accompanying migration, may have created advantageous alleles maintained in the context of evolutionary trade-offs.”
These two studies seek to find correlations between specific gene variants and the incidence of different diseases. Because of this, the research authors could not definitively prove that inheriting these ancient gene variants will certainly cause such diseases in modern Europeans.
Eske Willerslev, the project director and an evolutionary geneticist at the University of Cambridge (UK) and the University of Copenhagen (Denmark), stated: “What these studies are doing is establishing a framework for how you can use those ancient human gene pools to understand the origins and spread of disease risk.”
The ancient DNA research project led by scientists from the University of Cambridge and the University of Oxford has opened new insights into human genetic history, as well as having close ties to modern pathologies. International collaboration and support from museums and research organizations have made this project not only a scientific achievement but also an outstanding example of cooperation in international research.
