Identification of the NOR in the AFLP physical map. Pachytene FISH of BAC clone RH127D02 showed its localisation in the compound structure of the Nucleolar Organizer Region (NOR) on the short arm of chromosome 2 (see Tang et al.  for methodology). Both brighter fluorescing regions and relatively weaker ones are visible, suggesting differences in NOR chromatin density. In the AFLP physical map the NOR is represented by a 96-clone BAC contig containing RH127D02. In the WGP physical map this NOR contig is absent.