Genome-wide variation in recombination in female meiosis: a risk factor for non-disjunction of chromosome 21

Hum Mol Genet. 2000 Mar 1;9(4):515-23. doi: 10.1093/hmg/9.4.515.


Altered recombination patterns along non-disjoined chromosomes is the first molecular correlate identified for non-disjunction in humans. To understand better the factors related to this correlate, we have asked to what extent is recombination altered in an egg with a disomic chromosome: are patterns limited to the non-disjoined chromosome or do they extend to the entire cell? More specifically, we asked whether there is reduced recombination in the total genome of an egg with a non-disjoined chromosome 21 and no detectable recombination. We chose this subclass of non-disjoined chromosomes to enrich potentially for extremes in recombination. We found a statistically significant cell-wide reduction in the mean recombination rate in these eggs with non-disjoined chromosomes 21; no specific chromosomes were driving this effect. Most importantly, we found that this reduction was consistent with normal variation in recombination observed among eggs. Thus, given that recombination is a multifactorial trait, these data suggest that when the number of genome-wide recombination events is less than some threshold, specific chromosomes may be at an increased risk for non-disjunction. Further studies are required to confirm these results, to determine the importance of genetic and environmental factors that regulate recombination and to determine their impact on non-disjunction.

Publication types

  • Comparative Study
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Case-Control Studies
  • Chromosomes, Human, Pair 21 / genetics*
  • Female
  • Genetic Markers
  • Genome, Human*
  • Humans
  • Hybrid Cells
  • Meiosis / genetics*
  • Recombination, Genetic*
  • Risk Factors
  • Trisomy / genetics*


  • Genetic Markers