Interstitial telomeric-like repeat insertion at staggered double-strand break sites. (A,B) Two examples of telomeric repeat insertions associated with flanking sequence duplications. The inserted telomeric nucleotides are shown in red and the direct repeats flanking the insertion are shaded in blue; the direct repeats flanking the AluY transposon are boxed. (C) A staggered double-strand break can give rise to a duplication by a gap-filling mechanism (telomeric arrays: red boxes; direct repeats: light blue boxes). (HSA) Homo sapiens; (PTR) Pan troglodytes; (PPA) Pan paniscus; (GGO) Gorilla gorilla; (PPY) Pongo pygmaeus; (HLA) Hylobates lar; (HKL) Hylobates klossii; (PAN) Papio anubis; (PCR) Presbytis cristata; (MMU) Macaca mulatta; (CAE) Cercopithecus aethiops. (A) The human ITS locus is the AF237881 sequence from Chromosome 2q31; (B) AC026696, Chromosome 5q14.