PCR-RFLP of intron 2 of the Rhesus genes. An intron 2 polymorphism was analyzed by PCR amplification and digestion by PstI as previously described.25 Agarose gels are shown with fragment lengths25 and fragment specificities indicated. (A) The 1,177-bp product is specific for RHCalleles, the 1,068-bp product is representative for RHD orRHc or both. The CcD^VIee type III sample shows a strong band at the RHC position and a weaker band at theRHD/RHc position. In contrast, the CcD^VIee type II and the CcDee samples show a weak band at RHC position and a strong band at the RHD/RHc position. (B) The PCR products shown in (A) were digested with PstI to separate RHD fromRHc-specific products. The D^VI type III sample lacks the RHD-specific fragment (640 bp), whereas all other RhD positive samples show this fragment.