Neanderthal genes have been linked both to allergies and innate immunity, acting as an efficient protection against pathogens and also causing the body’s defenses to go into overdrive at times.
The discovery was made independently by two teams of scientists, whose scientific papers have been featured in the American Journal of Human Genetics on Thursday, January 7.
One group of researchers was led by Janet Kelso, at the Max Planck Institute for Evolutionary Anthropology, based in Leipzig, Germany.
As Kelso explained, around 2% of the human genome identified across Europe ans Asia has been inherited from the now-extinct Neanderthal population, which interbed with early Homo Sapiens in the early beginnings of the human race.
Based on an investigation across various regions of the human genome, meant to examine the prevalence of Neanderthal DNA in each of these sections, scientists discovered that a significant amount of Neanderthal genes are responsible for the way our immune system functions.
More precisely, these sequences have been identified as TLR6, TLR10 and TLR1, a triad of toll-like receptors which influences the way our body responds in the initial stages, after being confronted with pathogens such as Helicobacter Pylori.
These first reactions appear instinctively, and are present from the moment a person is born; in contrast, the adaptive or acquired immune system develops following vaccination or prior attacks from outside microbes.
On the one hand, DNA associated with innate immunity helps humans stave off hazardous bacteria, viruses and other types of infection, without giving enough time for the contamination to manifest itself.
On the other hand, such genetic makeup can also cause excessive response against other stimuli found in the environment. Namely, Neanderthal genes may explain why some people are more likely to be allergic to cats, dust mites, pollen or mold.
The other team which came up with similar findings was coordinated by Lluis Quintana-Murci, head of the Department of Genomes and Genetics, at the Institut Pasteur’s Center of Bioinformatics, Biostatistics and Integrative Biology, in Paris, France.
Researchers based their study on the 1000 Genomes Project, and analyzed a group of 1,500 DNA sequences associated with innate immunity, against the total distribution of Neanderthal genome components across the human population.
They discovered that genes related to the immune system, which have been passed on by these mysterious ancestors, are present among half the humans located in Europe, Central Asia and the Middle East.
According to Peter Parham, professor of structural biology, microbiology and immunology at the Stanford University School of Medicine, the highly astounding prevalence of this type of Neanderthal DNA across modern-day human beings is indicative of the fact that these genes represent a key evolutionary advantage.
Survival of the fittest allows just the most effective and beneficial characteristics to persist across tens of thosands of years, and since these sequences have withstood the test of time, they are obviously vital to humans.
Basically, without coexisting and mating with their Neanderthal neighbors, Homo Sapiens populations migrating from Africa to Europe and Asia around 50,000 years ago would’ve never managed to vanquish local pathogens lurking in these unfamiliar regions.
Although further research will allow this intriguing conclusion to be more thoroughly tested, it appears that modern-day human beings may be indebted to their Neanderthal ancestors for their ability to successfully conquer previously life-threatening infections.
On the other hand, this genetic inheritance may also be to blame for allergies and other pesky problems associated with an overactive immune system.
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