nondisjunction


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nondisjunction

[¦nän′dis‚jaŋk·shən]
(genetics)
Failure of homologous chromosomes to separate symmetrically during cell division, with both ending up in the same daughter cell instead of in each daughter cell.
References in periodicals archive ?
B chromosome nondisjunction in corn: control by factors near the centromere.
Edwards syndrome occurs because of meiotic nondisjunction.
For younger mothers, the mechanism behind the nondisjunction is not well understood.
Trisomy 21: association between reduced recombination and nondisjunction.
They have utility in mapping the A genome, in maize, modulating recombination, exploring the structure of the centromere and the process on nondisjunction, as well as other aspects of genome evolution (JONES et al.
Soybean (Glycine max) and tobacco (Nicotiana tabacum), formation of mosaicism which leads to leaf spots varying in their color and morphology; detection of somatic crossing over, chromosome deletions, nondisjunction and point mutations are used (Vig, 1982).
However, it does not appear that the process of microsporogenesis in Carex would prevent meiotic nondisjunction (Hoshino & Shimizu, 1986), and consequently it is not clear how it could play a role in limiting polyploidization.
This condition results from nondisjunction of the sex chromosomes during meiosis in parents.
The second "bit" is the elimination of the wild-type allele through nondisjunction, deletion, recombination, and/or chromosome loss and duplication This results in the primary mutation.
These plants must have experienced somatic loss or gain of single chromosomes following the chromosome doubling event, perhaps by nondisjunction.
The clones are assayed for autosomal meiotic nondisjunction by crossing clone-bearing females to males that carry a compound autosome (C(3)EN to screen 2L and C(2)EN to screen 3R).
Diploids may enter the population from several sources: chromosomal nondisjunction in tetraploid males producing haploid gametes, low level hermaphrodism in diploid females yielding self-fertilized embryos, and cross-contamination between diploid and triploid cultures (cf.