|Howard Temin, David Baltimore genetics
Meanwhile, this tiny enzyme (RNA-dependent DNA polymerase) generates DNA from an RNA template to help retroviruses replicate their genomes, and eukaryotic cells in creatures such as us extend their telomeres. Temin and Baltimore independently discovered this enzyme in Rous sarcoma and murine leukemia viruses.
They have no life outside of us. But yes they get inside our cells and use their own reverse transcriptase to produce DNA that an integrase enzyme incorporates into our cell’s DNA. Retroviral DNA produces protein chains that can do all sorts of damage including fevers, rashes, infections, immune system damage, cancer, and death.
Aliens have arrived and live inside us. Tiny spaceships injected their genomes. Secretly they fix our broken instructions.