SPERM NUCLEI ANALYSIS OF A ROBERTSONIAN T(14Q21Q) CARRIER, BY FISH, USING 3 PLASMIDS AND 2 YAC PROBES

The meiotic segregation of chromosomes 14 and 21 was analysed in 1116 spermatozoa from an oligo-asthenospermic carrier of a Robsertsonian translocation t(14q21q), and in 16 392 spermatozoa from a control donor, using two-colour fluorescence in situ hybridisation (FISH). Two YAC probes (cloned in yeast artificial chromosomes) specific for regions on the long arms of these chromosomes were co-hybridised. Of the spermatozoa, 12% were unbalanced, resulting from adjacent segregations. Chromosomes X, Y and 1 were also simultaneously detected in 1335 spermatozoa from the same carrier. Whereas gonosomal disomy rates were not significantly different from those of the control donors, disomy 1 were slightly but significantly increased to 0.7%. The diploidy rate was also slightly increased to approximately 1% in the translocation carrier.