Enhanceds are humans, but they have extra genomes which help them to adapt to survive, therefore giving them superpowers.

One of the many extra genes in an enhanced.

These extra genomes are believed by some to be artificial, and made by extraterrestrial life. The genomes were actually created by the Alals, an advanced alien race, which was wiped out by one of them, who decided for the enhanced DNA to breed inside of the humans, and he will return to Earth once the enhanceds have shown themselves.