Genomic rearrangements resulting from recombination between duplicons. (a) Interchromosomal recombination between direct repeats results in deletion and/or duplication. (b) Intrachromosomal recombination between direct repeats results in deletion. (c) Intrachromosomal recombination between inverted repeats results in an inversion. Repeated sequences are depicted as yellow arrows with the orientation indicated by the direction of the arrows. Recombination is shown by the red X. Upper- and lowercase letters refer to both alleles of the flanking unique sequence (e.g., A and a). Adapted in part fromLupski (1998).