Scientists have found evidence of evolutionary changes in Europeans over the past two to three thousand years. They found three traits in Europeans that are subject to constant pressure from natural selection.
The characterization of natural selection of complex traits is important for understanding human evolution. Scientists from the University of Shanghai (China) have conducted a comparative study of modern British people with people who lived throughout Europe several thousand years ago. The goal was to understand how natural selection influenced Europeans during this time. The work was published in the journal Nature Human Behavior.
Scientists analyzed data from the Biobank of Great Britain. In addition, they studied genetic material extracted from the remains of people who have lived in Europe for the past thousand years. The team then selected 870 polygenic traits and tried to quantify the selection signals. These traits are associated with specific genes and phenotypes and have been compared to genes in Europe in the past.
After examining the data, the researchers concluded that evolutionary selection works in 755 genes associated with traits that have formed over the past two to three thousand years. These included specific skin pigmentation, dietary habits (nutrient intake), and body size. It turned out that all three traits are under almost constant selection pressure, and this leads to continuous changes in the genome.
The change in skin pigmentation was quite expected, because it is known that early migrants to Europe had dark skin, but in the absence of intense sunlight, it lightened over time. Scientists have also found changes related to vitamin D intake, regulation of body temperature and body size. Similar things, the researchers believe, were caused by various weather changes.
However, it turned out that some of the expected changes did not occur. For example, the genetic correlates of inflammatory bowel disease and anorexia nervosa have not changed much. Scientists emphasize that these are only preliminary results and need further evaluation.