title: Acrocentric bivalents positioned preferentially nearby to the XY pair in metaphase I human spermatocytes.
abstract: OBJECTIVE
  To analyze whether the preferential proximity between acrocentric bivalents and the XY pair described at pachytene was maintained in metaphase I human spermatocytes.
  
  
  METHODS
  Proximity frequencies of autosomic bivalents to the sex bivalent were evaluated with the analysis of meiotic preparations combining sequentially standard techniques and multiplex fluorescence in situ hybridization.
  
  
  METHODS
  Assisted reproduction centers.
  
  
  METHODS
  Thirty-seven men consulting for fertility problems.
  
  
  METHODS
  Unilateral testicular biopsies.
  
  
  METHODS
  Proximity frequencies analysis to the XY pair, evaluated individually and grouping bivalents, was carried out using a logistical regression model with repeated measures.
  
  
  RESULTS
  Bivalents 22 and 15 were observed more frequently near to the sex bivalent than the others. Significant interindividual differences were not observed.
  
  
  CONCLUSIONS
  Results suggest that bivalents distribution to the metaphase plate is nonrandom. The maintenance of the acrocentric chromosomes' proximity to the sex bivalent from pachytene to metaphase I would indicate that the relative bivalents position would be notably preserved. The observation of non-interindividual variability, despite different infertility etiology, suggests that the nuclear organization pattern remains largely unaffected even if spermatogenesis is compromised.
authors.affiliation: Unitat de Biologia Cel·lular, Facultat de Biociències, Universitat Autònoma de Barcelona, Bellaterra, Spain. zaida.sarrate@uab.cat
authors.forename: Zaida
authors.initials: Z
authors.lastname: Sarrate
authors.forename: Joan
authors.initials: J
authors.lastname: Blanco
authors.forename: Francesca
authors.initials: F
authors.lastname: Vidal
mesh_terms: D001706:Biopsy; D002467:Cell Nucleus / Q000473:pathology; D041321:Chromosomes, Human, X; D041322:Chromosomes, Human, Y; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007248:Infertility, Male / Q000235:genetics* / Q000473:pathology*; D007621:Karyotyping; D016015:Logistic Models; D008297:Male; D008677:Metaphase; D049471:Pachytene Stage; D013090:Spermatocytes / Q000473:pathology*; D013737:Testis / Q000473:pathology*