FISH using DOP-PCR products. FISH using DOP-PCR products of the nanodissected duplication (1p)(p22-p23). Hybridization of the biotinylated probe DNA is detected with FITC-avidin (green signals). Chromosomes are counterstained with DAPI (blue). The tree signals show that the band (1p)(p22-p23) results duplicated in one of the two homologous chromosomes.