New research suggests that diversity in genes implicated in immunity might have facilitated the shift from hunter-gatherer lifestyles to agriculture that occurred in prehistoric Europe over the course of around 1,500 years.
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The agricultural revolution changed our societies and our genes
The agricultural revolution is considered one of the most important transformations to the human way of life that has ever happened. The shift from hunter-gatherer lifestyles facilitated the rise of modern civilization. It allowed humans to settle in one place, which led to the formation of towns and city-states that became the nucleus of early civilizations. Farming practices also forced humans to develop new tools and create pottery, developing their skill sets that they used in other applications.
8,000 years ago, Europe was home to a population of mesolithic hunter-gatherers. At this time, Neolithic farmers began moving into Europe from the east. Scientists have studied Europeans for many years to understand how our ancestors adapted to agriculture. Previous studies have revealed that in this period, human DNA underwent significant changes that resulted in height, skin color, digestion, and immune system alterations.
Understanding the role of immunity in Stone Age Europe
Now, scientists at the Francis Crick Institute have reported the results of their research that involved the study of DNA from 677 individuals who lived in Stone Age Europe roughly 8,000 years ago. Their findings suggest that diversity in genes coding for immunity that were already present in hunter-gatherer DNA facilitated the adaptation to the farming lifestyles of Neolithic farmers.
In looking for genes associated with hunter-gatherer ancestry, the team found that the major histocompatibility complex (MHC), the locus on DNA containing closely linked genes responsible for immune responses to disease, showed more hunter-gatherer ancestry than anticipated. The researchers theorize that these genetic variants in the MHC region were present in hunter-gatherers before the arrival of Neolithic farmers and were passed down preferentially. In looking at the MHC, the researchers also concluded that there was evidence of rapid evolution.
This research supports the idea that the transition from the hunter-gatherer lifestyle to farming is associated with increased natural selection on variants of genes linked with immunity. In addition, the team’s findings also show that diversity in such genes may be equally important to adaptation to lifestyle.
It is plausible that hunter-gatherers already had the genes to protect them from bacteria and viruses before the mesolithic farmers arrived, but it is also possible that it provided an advantage to have many different forms of these genes.
The researchers had expected to see more influence from Neolithic farmers in the MHC regions, given that later Neolithic people have far more ancestry from these early farmers. However, the team found a roughly 50:50 split in ancestry from Neolithic farmers and Mesolithic hunter-gatherers in this key, immune-associated region of the genome.
“At the moment, we’re not quite sure why this happened, but a proposal that the European hunter-gatherers had genetic variations which allowed them to fight Europe-specific disease. Or picking up a variety of genes from both hunter-gatherers and farmers was beneficial because it resulted in lots of diversity at this major group of genes, allowing people to better fight off disease.”
Tom Davy, Francis Crick Institute
Group leader of the Ancient Genomics Laboratory at the Francis Crick Institute, Pontus Skoglund, said: “By growing the ancient genomic record, we will be able to better understand the role of immunity in other periods of the human past.”
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