Identification of hGPA-Tg mice by mPCR. The presence of the GYPA Tg was detected using mPCR of gDNA extracted from biopsied tail tissue with the primers described in “Materials and methods.” This yielded a 219-bp band if the GYPA Tg was present. Amplification of the endogenous mouse glycophorin gene was used as an internal standard and yielded an 88-bp band in each case.