This family consists of bacterial and phage Gam proteins. The gam gene of bacteriophage Mu encodes a protein which protects linear double stranded DNA from exonuclease degradation in vitro and in vivo [1].

1: Purification of the gam gene-product of bacteriophage Mu and determination of the nucleotide sequence of the gam gene. Akroyd JE, Clayson E, Higgins NP; Nucleic Acids Res 1986;14:6901-6914. PMID:2945162