Fig. 3

Models for duplications and deletions of 22q11. Chromosome 22 is shown as a line. Black and red are used to distinguish the two homologs. Filled circles are used to indicate centromeres. LCRs are shown as blue or green boxes. A: Interchromosomal recombination between the two homologs of chromosome 22 leads to a deletion and duplication. B: Intrachromosomal recombination between LCRs on 22q11 leads to a deletion. C: Interchromosomal recombination between the two homologs of chromosome 22 leads to the formation of a bisatellited CES chromosome. D: Paracentric inversion within one homolog of chromosome 22 followed by recombination within an inversion loop leads to the formation of a CES chromosome.