Nondisjunction
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(Date:3/28/2011)... has discovered that descendants of "exploratory" butterflies that colonized ... The team, led by James Marden, a professor of ... post-doctoral scholar working at both Penn State and the ...
meiotic nondisjunction
the failure of two members of a chromosome pair to separate properly during meiosis, so that both members go to one daughter cell, and the other daughter cell receives neither ...
Disjunction: Separation of homologous chromosomes during anaphase of mitotic or meiotic divisions (see also nondisjunction).
nondisjunction The failure of chromosomes to separate properly during cell division. The unequal segregation of chromosomes during meiosis.
nondisjunction
[L. non, not + disjungere, to separate]
An accident of meiosis or mitosis, in which both members of a pair of homologous chromosomes or both sister chromatids fail to move apart properly.
nonpolar covalent bond ...
Nondisjunction The failure of a chromosome pair to separate at the first meiotic division, or for two chromatids of a replicated chromosome to separate at mitosis (or at the second meiotic division), so that both pass to the same daughter cell.
Nondisjunction
Nondisjunction occurs when chromosomes fail to "disjoin" during meiosis or mitosis.
Meiosis ...
Nondisjunction
Chromosome pairs do not disjoin (separate) during cell division so that both chromosomes go to one daughter cell and none to the other. Nondisjunction causes errors in chromosome number (trisomy).
Related Terms:
Chromosome ...
Nondisjunction- homologues don't separate in meiosis 1
Results in aneuploidy
Usually embryo lethal
Trisomy 21, exception leading to Downs syndrome
Sex chromosomes
Turner syndrome: monosomy X
Klinefelter syndrome: XXY ...
nondisjunction. Failure of a pair of homologous chromosomes to separate during meiosis, leading to one gamete with n + 1 chromosomes (see trisomy) and another gamete with n _ 1 chromosomes.
Ideal disjunction; discrepancy; contrariety.
8. Length or interval of time; period, past or future, between two eras or events. Ten years distance between one and the other. (Prior) The writings of euclid at the distance of two thousand years.
Nonclaret disjunctional (ncd) A member of the kinesin family of proteins that, in contrast with most family members, moves toward the negatively charged end of microtubules.
In humans, nondisjunction is most often associated with the 21st chromosome, producing a disease known as Down's syndrome (also referred to as trisomy 21).
The rate of non disjunction is correlated with maternal age. The probability of a woman having a fetus with a chromosome defect increases with age.
become more frequent as a woman ages.
Aneuploidy — the gain or loss of whole chromosomes — is the most common chromosome abnormality. It is caused by nondisjunction, the failure of chromosomes to correctly separate: ...
Advanced maternal age -- women over age 34 (age 35 at delivery) at increased risk for nondisjunction trisomy in fetus. Alcoholism -- a chronic and progressive condition characterized by the inability to control the consumption of alcohol.
Examples of major genetic principles established by Drosophila researchers in the early 1900s are nondisjunction and its consequences, the genetic behavior of chromosome aberrations, the mutagenicity of ionizing radiation, ...
Keywords: chromosomes, chromatid, centromere, cell cycle, interphase, mitosis, prophase, metaphase, anaphase, telophase, cytokinesis, meiosis, random segregation, diploid, haploid, Down's syndrome, non-disjunction, trisonomy, chromosome 21, ...
Trisomy
The term proposed by Blakeslee (1922) to describe an otherwise diploid individual which has one of the chromosomes represented three times instead of twice. Caused by nondisjunction during cell division.
 See also: Chromosome, Chromosomes, Cell, Cells, Nondisjunction
  
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