Cytological Monitoring of Meiotic Crossovers in Spermatocytes and Oocytes

Yan Yun, Masaru Ito, Sumit Sandhu, Neil Hunter

Research output: Chapter in Book/Report/Conference proceedingChapter


Crossing-over between homologous chromosomes is essential for accurate chromosome segregation at anaphase-I of meiosis. Defective crossing-over is associated with infertility, pregnancy miscarriage, and congenital disease. This chapter presents optimized protocols for the analysis of meiotic crossovers at the cytological level in spermatocytes and oocytes from mouse. The first approach employs immunocytology to detect MLH1, a DNA mismatch-repair protein that specifically marks crossover sites in the pachytene stage of meiotic prophase-I. These immunocytological methods have general utility for the analysis of other recombination steps, such as initiation and DNA strand exchange. The second approach visualizes chiasmata, the points of physical exchange between homologous chromosomes that are present during the diakinesis and metaphase-I stages. Both approaches are readily adaptable to the analysis of crossing over in other vertebrate species.

Original languageEnglish (US)
Title of host publicationMethods in Molecular Biology
PublisherHumana Press Inc.
Number of pages20
StatePublished - 2021

Publication series

NameMethods in Molecular Biology
ISSN (Print)1064-3745
ISSN (Electronic)1940-6029


  • Aneuploidy
  • Chiasma
  • Chromosome spread
  • Crossover
  • Homologous recombination
  • Meiosis
  • MLH1
  • Oocytes
  • Spermatocytes

ASJC Scopus subject areas

  • Molecular Biology
  • Genetics


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