We inherited allergies and a strong immune system from Neanderthals according to the findings of two new studies published in the American Journal of Human Genetics.
Thousands of years back, modern humans and Neanderthals started interbreeding. As the two species came together, new gene variations also surfaced, bringing about significant differences. It seems that among these gene variations, a set gave a healthy boost to the immune system. However, we inherited allergies and a strong immune system from Neanderthals.
The two studies have emphasized the role of interspecies relations in the fascinating process of human evolution. Moreover, our innate immune system was placed under the limelight. According to Janet Kelso with the Max Planck Institute for Evolutionary Anthropology (Leipzig, Germany):
“We found that interbreeding with archaic humans–the Neanderthals and Denisovans–has influenced the genetic diversity in present-day genomes at three innate immunity genes belonging to the human Toll-like-receptor family.”
Lluis Quintana-Murci with the Institut Pasteur and CNRS (Paris) added that in addition to these, other innate immunity genes were found to be more common with the Neanderthals than any other genomes studies. Thus, our innate immune system stole the spotlight through the Neanderthal ancestry it presented.
It has already been shown in previous studies that 1 to 6 percent of the Eurasian genomes today present Denisovan or Neanderthal ancestry. TLR genes mentioned by Janet Kelso are immune receptors expressed at the level of a cell’s surface. Here, they are crucial for detecting and then fending off bacteria or parasites creating a host of problems.
The findings of the two studies were the result of extensive research on the evolution of our innate immune system starting with the interspecies breeding between modern humans and the Neanderthals. Data retrieved from the 1000 Genomes Project in addition to available genome sequences from ancient hominis were studied for the two independent researches.
Both research papers found very little variation for a host of innate immunity genes over long periods of time. However, they also showed that some genes have undergone sweeps which triggered a strengthening process.
These sweeps may have been sparked by endemic disease as well as environmental changes. The hypothesis is also supported by the fact that the research teams found the gene adaptations occurred as the transition from hunting to farming was also taking place.
Photo Credits: Wikimedia