Gamma was the term applied to the original Jem'Hadar soldiers created in the Gamma Quadrant after the creation of the Alphas in 2374. The Gammas were regarded as inferior to the Alphas, leading to friction between the two groups. (DS9: "One Little Ship")
Gammas were distinguished by a darker complexion and a bony Mohawk-like ridge down the center of their scalps.
List of Gammas