Our DNA includes the DNA of probably defunct viruses. Viruses operate by making host cells create more of the virus’ DNA. Some of that stuck. Within our DNA is the DNA of ancient viruses that have become part of us. Surprise! Just as we now know that the majority of the cells in our bodies aren’t us, but are bacteria and such, some of our DNA isn’t really ours. The supposition is that the virus DNA is inactive. The possibility exists that it is like a vaccine, or the remnants of an immune response from generations ago. The other possibility exists that it may reactivate – in unpredictable ways. We continue to better understand who and what we are, and discoveries continue.
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