phi29-XT DNA Polymerase is efficient at amplifying circular DNA by Rolling Circle Amplification (RCA) as well as genomic DNA by Multiple Displacement Amplification (MDA). However, the phi29-XT polymerase included in the phi29-XT WGA Kit (NEB #E1604) has been formulated to reduce GC bias during amplification of human genomic DNA. For RCA, we suggest using the phi29-XT RCA Kit (NEB #E1603).