Analysis of segregation in a human male reciprocal translocation carrier, t(1;11) (p36.3;q13.1), by two-colour fluorescence in situ hybridization.

Using centromeric probes specific for chromosomes 1 and 11, 13,071 sperm nuclei from a male reciprocal translocation heterozygote, 46,XY,t(1;11) (p36.3;q13.1), were analyzed by fluorescence in situ hybridization (FISH). Decondensed sperm nuclei were simultaneously hybridized with DNA probes for chromosome 1 (pUC177) and chromosome 11 (D11Z1). Results were as follows: 1/11 (82.45%), 1/1/- (3.45%), -/11/11 (4.85%), 1/1/11 (1.20%), 1/11/11 (1.14%), 1/- (4.33%), -/11 (2.50%), 1/1/11/11 (0.06%), 1/1/1/- (0.02%). Because both the normal chromosome and its translocated derivative carry the same centromeric sequences, FISH cannot differentiate between sperm resulting from alternate segregation and those produced by adjacent I segregation. Using the same donor, comparable segregation patterns were obtained from sperm chromosome karyotypes (Spriggs et al., 1992: Hum Genet 88:447-452) and from MII spermatocytes (Goldman and Hulten, 1993: Cytogenet Cell Genet 63:16-23), demonstrating that selection is not a factor in the human sperm/hamster oocyte fusion technique or during meiosis. Although FISH does not provide the detailed information afforded by sperm karyotyping, it is a valuable technique for studying segregation patterns in translocation heterozygotes.