"On the contrary, humans were created by the Ancients." Carson frowns. "It's a wee bit complicated, but the Ancients were the first evolution of this form, and they were dying because of a plague." He folds his arms. "In order to make sure life survived, they reseeded the Milky Way galaxy with life in their image; Us. Well. Earth Humans. After that, they fled to the Pegasus Galaxy on Atlantis, a giant cityship, and seeded Pegasus with human life, too."

And then he frowns slightly.

"Although we never confirmed this, we suspect the nanovirus was made in response to a threat in the Pegasus Galaxy. The Wraith. They're a vampire-like species that suck the life energy out of humans to feed, so the nanovirus could have been made to cull the Wraith's feeding ground."