Meiotic recombination in human oocytes

PLoS Genet. 2009 Sep;5(9):e1000661. doi: 10.1371/journal.pgen.1000661. Epub 2009 Sep 18.


Studies of human trisomies indicate a remarkable relationship between abnormal meiotic recombination and subsequent nondisjunction at maternal meiosis I or II. Specifically, failure to recombine or recombination events located either too near to or too far from the centromere have been linked to the origin of human trisomies. It should be possible to identify these abnormal crossover configurations by using immunofluorescence methodology to directly examine the meiotic recombination process in the human female. Accordingly, we initiated studies of crossover-associated proteins (e.g., MLH1) in human fetal oocytes to analyze their number and distribution on nondisjunction-prone human chromosomes and, more generally, to characterize genome-wide levels of recombination in the human female. Our analyses indicate that the number of MLH1 foci is lower than predicted from genetic linkage analysis, but its localization pattern conforms to that expected for a crossover-associated protein. In studies of individual chromosomes, our observations provide evidence for the presence of "vulnerable" crossover configurations in the fetal oocyte, consistent with the idea that these are subsequently translated into nondisjunctional events in the adult oocyte.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adaptor Proteins, Signal Transducing / metabolism
  • Adolescent
  • Adult
  • Chromosomes, Human / genetics
  • Confidence Intervals
  • Female
  • Fetus / cytology
  • Genome, Human / genetics
  • Humans
  • Meiosis / genetics*
  • MutL Protein Homolog 1
  • Nuclear Proteins / metabolism
  • Oocytes / cytology*
  • Oocytes / metabolism*
  • Protein Transport
  • Recombination, Genetic*
  • Sister Chromatid Exchange / genetics
  • Time Factors
  • Trisomy / genetics
  • Young Adult


  • Adaptor Proteins, Signal Transducing
  • MLH1 protein, human
  • Nuclear Proteins
  • MutL Protein Homolog 1