"It is a difficult concept to get one's head around. Parasites, to us, are derivative, necessarily descendant from the biological entities they depend on for life. But simple does not always mean less evolved. Mimi's outsize complement of genes--so large that the virus is tantalizingly close to being an independent organism--suggest to many scientists that Mimivirus underwent reductive evolution early on and shed some of its genome, including the genes necessary to replicate on its own."
"The implications of that finding are truly radical: that Mimi, or a Mimi-like ancestor, emerged prior to the three other domains and played a key role in inventing the very cells of which humans and all complex cellular life-forms are made."