Expression of h-IFNγ over repeated rounds of subculturing in the absence of selection pressure. E.coli DH5α transformed with pCR2-IFNγ and pGP1-2 were grown without ampicillin at 30°C with subculturing for six days. Total cell lysates run on 15% SDS-PAGE. Lane 1: 4th hr post induction sample from Day 1. Lane 2: Protein molecular weight marker. Lane 3: Uninduced culture Lane 4–8: 4th hr post induction samples from day 2 to day 6.