Diagram of iPCR validation of inversions mediated by inverted repeats (IRs).

<p>Standard and inverted arrangements are represented by unique regions A, B, C and D, which are separated by IR1 and IR2 at each inversion breakpoint (BP). The iPCR involves three steps: digestion at the restriction enzyme target sites (RE), circularization of the digested fragments by self-ligation, and PCR amplification with primers (small arrows) flanking the restriction site to generate products of different size depending on the orientation of the segment between both repeats.