Around the 15th century, European settlers migrated towards America, coming in contact with Native Americans. Not only did they bring new perspectives on religion, but they brought diseases that ultimately killed a large number of Native Americans. Researchers have begun a study on how diseases stemming from the 15th century have affected the modern immune system genetically.
The immune system is designed to protect your body against bacteria, toxins, viruses, etc. As your body becomes infected, the antibodies, proteins that attack viruses, fight it off for the first time. If the same infection enters your body again, then these antibodies are able to recognize it much faster, and respond accordingly.The Europeans were typically more exposed to smallpox, measles, and influenza. Different antibodies were developed due to the diversity of disease and the different groups of people affected with these diseases.
A research team has decided to analyze the DNA from the remains of 25 people that lived in the general area 500-6000 years ago. Most of these remains were from those who encountered Europeans in the 1700s. They used a process called whole exome sequencing. They searched for genes related to the immune system. They also sequenced 25 current Tsimshian residents. After comparing both sequences, researchers noticed that some variants of the genes related to the immune system were rare among those that were living. HLA-DQA1 is one of those genes that was found in all ancient people but only found 36% of the time in the living ones.
Researchers believe that these genes were adapted to the local diseases but not to the new ones. They predict that the genetic shift occurred about 175 years ago. After this finding, researchers would also like to do a study on the immune related genes in other Native American communities.
This study is very interesting because it explains how the immune system has changed over time. It didn't just evolve as a way of being able to fight off infections much easier. It evolved with the genetic aspect as well, leading to much more research that could possibly be done.