The concept that microbes such as those in the gut and skin contribute to human health is not new. In fact, scientists have also discovered that hundreds of thousands of DNA fragments in the human body are derived from viruses; these fragments were embedded in the human body long ago and passed down from generation to generation; and these DNA fragments and the viruses from which they are derived are known as “endogenous retroviruses”.
What do these viral DNA do to the human body? It was not until recent years that people discovered that these foreign genetic materials may also play a role in boosting human immunity.
