"I Put My Blue Genes On" is a short story by Orson Scott Card. It appears in his short story collections Unaccompanied Sonata and Other Stories and Maps in a Mirror. It was first published in the August 1978 issue of Analog.
The story takes place far in the future. Earth
has become an uninhabitable wasteland of biological warfare
. After fleeing Earth decades earlier, a contingent of humans returns to find a small band of beings, now not quite human, still fighting an enemy which has long since been annihilated. The title refers to the planet's surface, which has become a swirling mass of blue goo, a result of the biological agents acting and reacting one with another.