Identification of genomic rearrangements by PCR. The initial (■) and terminal (□) repeats of an AMPL, and the recombinant structures characteristic of the del (╡) and of the amp (╞) of the AMPL are shown. The position of the PCR primers is shown by arrows. a, FP of the initial repeat; b, RP of the initial repeat; c, FP of the terminal repeat; d, RP of the terminal repeat.