Simultaneous detection of structural and numerical chromosome abnormalities in sperm of healthy men by multicolor fluorescence in situ hybridization

Abstract

Both structural and numerical chromosome aberrations in sperm represent important categories of paternally transmitted genetic damage. Therefore, a new multiprobe fluorescence in situ hybridization (FISH) method, using DNA probes for three targets (centromere and telomere of chromosome 1, centromere of chromosome 8), was developed to detect human sperm carrying three types of chromosomal defects: (1) terminal duplications or deletions in chromosome 1p, (2) aneuploidy involving chromosomes 1 or 8, and (3) diploidy. Baseline frequencies were determined for three healthy donors who had been previously evaluated for sperm cytogenetics by the human-sperm/hamster-oocyte cytogenetic technique (hamster technique). Among ∼120 000 sperm analyzed by the new FISH method, the average baseline frequencies of sperm carrying telomeric duplications and deletions of 1p were 3.2 ± 1.9 and 2.9 ± 3.6 per 10⁴, respectively. Diploid sperm was found in an average frequency of 6.6 ± 4.0 per 10⁴. Average frequencies of disomic sperm for chromosomes 1 or 8 were 1.7 ± 2.2 and 1.9 ± 2.3 per 10⁴, respectively. Inter-individual differences were observed for deletions of 1p but not for the other sperm phenotypes. A good correlation was obtained between the frequencies of sperm with structural chromosome aberrations detected with the new assay and the frequency of sperm carrying premeiotic or meiotic cytogenetic damage detected with the hamster technique. The observed levels of numerical aberrations with the new FISH assay were within range of the baseline frequencies reported by the hamster technique. The newly developed FISH assay has promising applications in genetic, clinical, physiological and toxicological studies.