Schematic representation of the multi-step gr/gr deletion screening procedure and categories of gr/gr subtypes defined. A) Gene dosage and RFLP analysis was used to i) distinguish between “simple” gr/gr deletions, false deletions and deletion/duplications events and ii) to define the missing gene copies, i.e. gr/gr deletion subtypes (examples of electropherograms shown; see Materials and Methods for further details). (*) STS: Sequence Tagged Site-based PCR method, according to Repping et al. [9]. B) Molecular characterization of the different gr/gr rearrangement types. Gene dosage of CDY1 and DAZ and the possible combinations on the basis of missing DAZ (DAZ1/DAZ2/DAZ3/DAZ4) and CDY1 (CDY1a/CDY1b) copy types are shown for each rearrangement. “+” and “-” represent positive and negative results, respectively. * in the AZFc region: sY142, sY1258, sY1161, sY1197, sY1191, sY1206, sY1201. § 6 cases showed a combination of DAZ copies from each DAZ duplex, possibly DAZ1/3 or DAZ3/4. Abreviations: del=deletion; dupl=duplication; ampl=amplification.