The star genome is a specific genetic profile which appears to allow one the potential to manipulate and interface with the fundamental forces of the universe. Much about its specifics are unknown.
Dr. Brahman abducted and conducted genetic experiments on homeless orphaned children to artificially synthesize the star genome and create two "angels", which would possess the ability to freeze the world's flow of time. They were brainwashed and implanted with what was known as the "angel egg". Most of the subjects were not compatible and did not survive however, except for two sisters named Kali and Durga. Brahman was not able to fully complete the star genome however, and it was still imperfect. The final component needed to perfect the star genome appeared connected to the gravity engine at Neu Hiraleon. Brahman had the children taken here and placed into what was known as the "cradle", while the gravity engine was set to an increasingly critical state in an attempt to awaken the star genome, but was unsuccessful. In the process, a massive Gravity Storm emerged, pulling in Neu Hiraleon and the cradle. While a setback, the robot Brahman programmed to overlook the process deduced that there were still other alternatives, and pleaded for the "angels" to find their way back to Hekseville again.
At some point following the accident, Kali's star genome was perfected and she was able to return to Hekseville. Later when Durga, now known as Cecie, came into direct contact with the gravity engine again, her hibernating star genome became awakened and was completed, restoring her old memories as Durga. When she reunited with Kali, she underwent a transformation into Durga Angel.
Kat herself is suggested to also possess this genetic profile, as when Durga did not return to Hekseville as Kali did, Brahman requested Kat to take her place and become the second angel in his project. From this it can be inferred that Gravity Shifters also possess the star genome, including Raven and Cai. It can be deduced from this that the star genome lies within the Eto royal family bloodline, connecting them to their guardians, which allows them power over the fundamental forces of gravity.