The most extensive genetic database of ancient humans to date is providing new insights into contemporary medical conditions, such as multiple sclerosis (MS), and shedding light on the variability in heritable traits like height among different populations.
One significant discovery suggests that genes associated with MS may have proliferated due to their role in defending against infections transmitted from animals.
Other findings include explanations for the varying prevalence of Alzheimer’s disease among different ethnic groups and the height disparities observed between individuals from northern and southern Europe.
Evan Irving-Pease, from the University of Copenhagen in Denmark, emphasizes the significant impact ancient events can have on the health and longevity of present-day populations.
The genetic makeup of individuals with European and west Asian ancestry has been influenced by three major migration waves: the arrival of hunter-gatherers around 45,000 years ago, followed by Middle Eastern farmers about 11,000 years ago, and subsequently by Eurasian steppe herders known as the Yamnaya.
To explore how these migrations shaped modern medical conditions, Irving-Pease’s team analyzed bone and teeth samples from nearly 5000 ancient remains found in museum collections across Europe and west Asia, with some specimens dating back 34,000 years.
Their latest research focuses on approximately 1600 individuals and compares their genetic data with that of 410,000 individuals from the UK Biobank, specifically targeting those of European descent.
The initial focus was on MS, an autoimmune disorder where the immune system attacks nerves, often leading to progressive disability. Previous studies identified 233 genetic variants associated with a higher MS risk.
The team found that individuals in the UK with a greater genetic susceptibility to MS also had more Yamnaya ancestry. Some of the MS-linked genetic variants originated in the Yamnaya and became more prevalent as they migrated westward through Europe.
Given that some of these MS-associated variants also impact the immune system, and considering the Yamnaya’s close proximity to animals, the researchers suggest that these genes may have aided in defending against bacteria and viruses transmitted from animals.
In another study, the researchers explored how ancestry influences genetic susceptibility to Alzheimer’s disease. They found that individuals with more ancestry from early European hunter-gatherer populations are more likely to carry the ApoE4 gene, associated with a higher risk of Alzheimer’s.
Conversely, an alternative variant of this gene, ApoE2, which lowers Alzheimer’s risk, seems to have emerged in the Yamnaya, possibly due to its protective effects against malaria or other viral infections.
Additionally, the analysis revealed that individuals with more Yamnaya ancestry in Europe tend to be taller, potentially explaining the height differences between populations in northern and southern Europe.
