Definition of non-disjunction in English:



  • [mass noun] The failure of one or more pairs of homologous chromosomes or sister chromatids to separate normally during nuclear division, usually resulting in an abnormal distribution of chromosomes in the daughter nuclei.

    • ‘The origin of the extra chromosome 21 due to meiotic non-disjunction was 79.24 per cent maternal and 20.76 per cent paternal.’
    • ‘Although the non-disjunction of chromosome 21 in cultured lymphocytes was reported to be increased by age, there was no age or sex effect on chromosome 21 micronucleation in healthy persons.’
    • ‘Although this assay is very sensitive for detecting chromosomal loss, it is unable to detect non-disjunction and chromosome gain.’
    • ‘In principle, non-disjunction during spermatogenesis could lead to aneuploidy, which might cause fetal death.’
    • ‘For example, a family history of multiple relatives with Down syndrome suggests an inherited translocation, not sporadic non-disjunction.’