FISH analysis with locus-specific probes in sperm from two translocation carrier men

Meiotic segregation of normal and derivative chromosomes was analysed in sp erm samples from two balanced reciprocal translocation carrier men by use o f dual-colour fluorescence in situ hybridisation (FISH) technique. The tran slocations were t(4;8)(p15;p12) and t(15;22)(q(23;q13.2), and the digoxigen in-labelled FISH probes were specific to either the translocated or centric segments of the chromosomes involved in the translocations. A total of 100 0 spermatozoa for each probe were analysed and the modes of segregation wer e described on the basis of signals in each sperm cell. The mean frequency of alternate and/or adjacent-1 (adj-1) segregation types was 69.47%, wherea s they were 30.51 and 78.70% for the adjacent-2 (adj-2) and alternate/adj-2 segregation types, respectively. This study illustrated that FISH is a val uable technique for analysing the meiotic segregation products of the heter ozygotes in respect to aneuploidy risk.