Structure of the fusion point. (A) Restriction maps of the JT-specific fragment and the normal 1q21 allele. The restriction enzymes used are: B, Bgl I; E, EcoT14 I; H,Hinf I; T, Tsp509 I. The position of probe A is shown. (B) The nucleotide sequences of the fusion point of the jumping translocation. The fusion point of 1q21 was determined by a sequence comparison between the JT-specific fragment and the normal 1q21 allele. The telomeric regions (indicated by capital letters) found at the fusion point were composed of variant repeats, such as TTGGGG, TGAGGG, and TCAGGG (indicated by italic letters), along with the authentic telomeric repeats (TTAGGG). The subtelomeric sequence distal to the variant repeat is underlined. The unique nucleotide sequence derived from 1q21 is indicated by small letters.