Actually, retroviruses have contributed ~8% of human DNA, so you could say that past rootkits have been incorporated into the current ("OS") platform. I underst

Actually, retroviruses have contributed ~8% of human DNA, so you could say that past rootkits have been incorporated into the current ("OS") platform. I understand the mammalian placenta required the added viral genetic components to evolve. These retrovirus fragments can surface as "transposons" where they will copy themselves up to thousands of times over the DNA of the cell, which can happen about once a month. There are also "gypsy transposons" that encapsulate these viral fragments in a package that can "infect" a neighboring cell. Germline cells have special mechanisms to silence transposon activity, otherwise reproduction would be much more problematic.