Gamma team was an android replica team of SG-1 created by the rogue NID. The team's goal was to collect advanced alien technology for NID so that it could be sent to Earth and used to defend Earth from the Goa'uld and other foreign threats.
History[]
After Theta team went rogue, Gamma O'Neill and Teal'c vanished and Carter and Jackson accompanied the project head Carlos Mendez to the NID's Beta Site, P4H-268. However, Carter and Jackson killed the rest of the NID personnel while Mendez was sleeping and destroyed all of the duplicating equipment, but prepared the power equipment to take with them. When Mendez woke up, O'Neill and Teal'c returned, having found a suitable site for their operations. Mendez managed to take Teal'c out with a P90 and damaged O'Neill before O'Neill killed him with a pistol.
When the real SG-1 arrived at the Beta Site, they found Mendez's body as well as the Gamma Teal'c and O'Neill's. Pinned to the Gamma O'Neill's chest was a message written by the Gamma Jackson reading "you're welcome." The Gamma O'Neill appeared to have chosen to remain there and allow himself to run out of power, but there was no sign of the other Gammas.
Having left the Beta Site, Gamma Jackson made contact with Mike Talbot, their handler on Perseus. It is unknown what happened to the remainder of Gamma team following this. (SG1: "Hydra")