The relationship between meiotic recombination in human spermatocytes and aneuploidy in sperm

BACKGROUND: We have previously demonstrated that a decreased recombination frequency between human X and Y chromosomes is associated with the production of aneuploid 24,XY sperm. This study's aim was to determine the relationship between recombination frequency in human pachytene spermatocytes and aneuploidy frequencies in individual chromosomes in sperm from the same men. METHODS: Six previously fertile vasectomy reversal patients donated testicular tissue for meiotic analysis of pachytene spermatocytes using immunocytogenetic techniques for visualization of the synaptonemal complex and recombination sites (MLH1). Individual meiotic chromosomes were identified with centromere-specific multicolor fluorescence in situ hybridization (FISH), and the number of MLH1 signals was recorded for individual chromosomes. An ejaculated sperm sample was obtained from each patient 2-26 months post-reversal for FISH analysis of sperm aneuploidy frequencies of chromosomes 1, 9, 13, 21, X and Y. RESULTS: There was no significant correlation between meiotic recombination frequency and sperm aneuploidy for any individual chromosome. Similarly, there was no correlation between aneuploid sperm and bivalents with no recombination. CONCLUSIONS: The study provides unique data on intra-individual human recombination and aneuploidy events. It also demonstrated for the first time that men do not have an increased frequency of sperm aneuploidy 5-9 years post-vasectomy.