Related Experiment Video
Updated: Aug 22, 2026
Preparation of Meiotic Chromosome Spreads from Mouse Oocytes for Assessment of Synapsis and Recombination
Published on: July 18, 2025
Identification of meiotic anomalies with multiplex fluorescence in situ hybridization: Preliminary results
Zaida Sarrate1, Joan Blanco, Susana Egozcue
1Unitat de Biologia Cel.lular, Edifici Ciències, Universitat Autònoma de Barcelona, Bellaterra 08193, Spain.
Objective:
To characterize meiotic anomalies in infertile men by multiplex fluorescence in situ hybridization (M-FISH) and to determine whether synaptic problems affect specific bivalents or whether anomalies are random.
Design:
Analysis of meiotic preparations with standard techniques and M-FISH.
Setting:
Assisted reproduction centers and Universitat Autònoma de Barcelona.
Patient(S):
Three fertile men undergoing vasectomy, four sterile patients with oligoasthenoteratozoospermia, and one patient with a Robertsonian translocation t(13;14).
Intervention(S):
Unilateral testicular biopsy in controls and patients with oligoasthenoteratozoospermia and collection of a semen sample from the translocation carrier.
Main Outcome Measure(S):
Identification of bivalents in metaphase I and chromosomes in metaphase II and characterization of chromosome abnormalities.
Result(S):
All bivalents in metaphase I and all chromosomes in metaphase II could be identified. In controls and in one patient with oligoasthenoteratozoospermia, meiosis was normal. Other patients with oligoasthenoteratozoospermia showed different types of anomaly: desynapsis, breaks, precocious XY separation, or cryptic reorganizations. The Robertsonian translocation t(13;14) was easily identified.
Conclusion(S):
Results confirm the high incidence of synaptic errors in oligoasthenoteratozoospermia patients. Bivalents in metaphase I and chromosomes in metaphase II were individually identifiable. Nondisjunctional errors or small reorganizations overlooked in classic meiotic preparations were identified. Synaptic anomalies seem to affect meiotic bivalents at random.
