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 ?
Altered recombination has an effect on nondisjunction (Ferguson et al.
The majority of aneuploidy is believed to be due to nondisjunction during meiosis (4).
On the other hand, it has been postulated that chemicals inducing crosslinks increase the probability of chromosomal nondisjunction (7,17).
The recently established 4-fold increase in maternal risk of having a child with Down syndrome, when affected by abnormal folate metabolism (35), has shown that pathologic conception is the culprit of meiotic nondisjunction in this continuum of pregnancy wastage.
Thus, the probability that a hit in the embryonal DNA will cause a nondisjunction depends on dose rate at that time; cumulative dose over a longer period is not relevant.
Although increasing maternal age is irrefutably associated with an increased risk of nondisjunction in the oocyte, the relationship between paternal age and the frequency of nondisjunction has not been clearly elucidated.