3-PROBE FLUORESCENCE IN-SITU HYBRIDIZATION TO ASSESS CHROMOSOME-X, CHROMOSOME-Y, AND CHROMOSOME-8 ANEUPLOIDY IN SPERM OF 14 MEN FROM 2 HEALTHY GROUPS - EVIDENCE FOR A PATERNAL AGE EFFECT ON SPERM ANEUPLOIDY

The method of simultaneous three-chromosome fluorescence irt situ hybr idization (FISH) was developed using repetitive DNA sequence probes fo r chromosomes 8, X and Y and applied to semen of 14 men from two healt hy groups who differed in their average ages (46.8 +/- 3.1 years, n = 4 v. 28.9 +/- 5.0 years, n = 10). The frequencies of disomic sperm det ermined by FISH compared well with frequencies obtained using the hams ter-egg technique for human-sperm cytogenetics and with the frequencie s of disomic and diploid sperm reported in previous FISH studies in th is laboratory. The two groups of men did not differ in their baseline frequencies of sperm disomic for chromosome 8 (similar to 6.5 per 10(4 ) sperm), sperm with XY8 aneuploidy (similar to 9.5 per 10(4) sperm), or sperm with autodiploidy XX88 or YY88 (similar to 2 per 10(4) sperm) . However, the older group had statistically higher frequencies of spe rm carrying sex chromosomal disomy than the younger group (5.1 v. 2.2 per 10(4) sperm for XX8; 5.9 v. 2.0 per 10(4) sperm for YY8; P < 0.005 ). A recent report from this laboratory of sex-chromosomal aneuploidy in sperm of aged mice provides inter-species corroborating evidence fo r this preliminary finding of a paternal age effect on sperm aneuploid y in human males.