PFGE analysis of DNA from a lymphoblastoid cell line to localize the PAR-1 and PAR-2 genes. Fragment size was assigned using the λ multimer ladders (λ). (A) The largest fragments obtained withAsc I (A), Nru I (Nr), and Not I (N) are common to PAR-1 and PAR-2 whereas the smallest obtained with SacII (S) are specific for each probe. PFGE conditions: ramp from 110 to 140 seconds for 64 hours. (B) By varying the electrophoretic conditions (pulse time of 30 seconds for 24 hours, ramp from 30 to 40 seconds for 24 hours and then 40 seconds for 24 hours), we achieved an improved separation of the different 110-kb and 130-kb fragments. Whichever the combination of enzymes used (Not I, BssHII [B],SacII), each probe gave an identical pattern, indicating that the cutting sites for these enzymes are clustered.