The Covid-19 pandemic has certainly changed millions of lives forever, but many scientists wonder how the pandemic could affect the human genome. In a 2022 article in US news, researchers studied the Black Death, the 14th-century pandemic that wiped out nearly 25 million Europeans, and in particular, how it affected our bodies.
According to researchers, the Black Death led our bodies to select for certain genetic traits which at the time decreased their risk of infection. These specific genes increased the activity of the immune system to better help fight the plague, however, today these mutations are having dangerous consequences. Researchers have noticed a connection between such genes and the risk of numerous conditions, such as Crohn’s Disease, Lupus, and Rheumatoid Arthritis. These illnesses are known as Autoimmune Diseases, a class of illnesses that occurs when the body tricks itself into attacking its own cells.
These specific genes increased the activity of the immune system to better help fight the plague, however, today these mutations are having dangerous consequences
According to LibreTexts, this phenomenon occurs when certain pathogens have a very similar molecular structure to the antigens that our bodies produce. Therefore, our bodies are tricked into attacking their own cells thinking that they are pathogens. This destroys important structures in our bodies, the absence of which causes illness, such as Crohn’s disease and Rheumatoid Arthritis.
According to Dutch biologist Henrik Poinar of McMaster University, “A hyperactive immune system may have been great in the past.” This hyperactivity may have led to an increase in activity against the plague, which in turn could have increased survival rates. This groundbreaking research suggests that even the shortest event of monumental importance can forever change our bodies. As stated by senior researcher Luis Bareirro, “Our genome today is a reflection of our whole evolutionary history.”
The obvious question here is: will our current Covid-19 pandemic affect our bodies and are our bodies evolving? Researchers say no. According to Barreiro, Covid’s low fatality rate makes it unlikely to cause any significant genetic change. However, Covid’s mutations are difficult to predict, and we have no way of knowing how future mutations will affect our bodies. Furthermore, in a recent study from Stanford Medical school, researchers identified 1,000 genes linked to severe Covid infection. It is theoretically possible for these genes to be selected for as we evolve, and it is unclear how that could affect our ancestors.
Covid’s low fatality rate makes it unlikely to cause any significant genetic change
This selection is similar to the selection we are performing on fast-growing flowers in Biology class. Like the removal of flowers without hairs, certain human genetic traits (probably not hairs) perform more favorably in a pandemic environment and may prevail due to natural selection.
While it is impossible to know what the future will hold, it is interesting to analyze how major historical events, like the Black Death, have affected our bodies. While there isn’t consensus around how the current pandemic will affect our ancestors, scientists agree that these events are clearly linked to our evolution as a species. According to Barreiro, “It’s not going to stop. It’s going to keep going for sure.”