nondisjunction of chromosomes

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• Nondisjunction — ( not coming apart ) is the failure of chromosome pairs to separate properly during meiosis stage 1 or stage 2. This could arise from a failure of homologous chromosomes to separate in meiosis I, or the failure of sister chromatids to separate… …   Wikipedia

• nondisjunction — [nän΄dis juŋk′shən] n. Biol. the failure of paired chromosomes to pass to separate cells in meiosis …   English World dictionary

• Nondisjunction — Failure of paired chromosomes to 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 such as trisomy 21 (Down s syndrome) and monosomy X …   Medical dictionary

• nondisjunction — noun Etymology: International Scientific Vocabulary Date: 1913 failure of homologous chromosomes or sister chromatids to separate subsequent to metaphase in meiosis or mitosis so that one daughter cell has both and the other neither of the… …   New Collegiate Dictionary

• nondisjunction — n. a condition in which pairs of homologous chromosomes fail to separate during meiosis or a chromosome fails to divide at anaphase of mitosis or meiosis. It results in a cell with an abnormal number of chromosomes (see monosomy, trisomy) …   The new mediacal dictionary

• nondisjunction — noun meiosis in which there is a failure of paired homologous chromosomes to separate; results in an abnormal number of chromosomes in the daughter cells • Hypernyms: ↑meiosis, ↑miosis, ↑reduction division …   Useful english dictionary

• nondisjunction — n. [L. non, not; disjunctus, unyolked] The failure to separate of paired chromosomes during meiosis …   Dictionary of invertebrate zoology

• nondisjunction — /non dis jungk sheuhn/, n. Biol. the failure of chromosomes to separate and segregate into daughter cells at division. [1910 15; NON + DISJUNCTION] * * * …   Universalium

• nondisjunction — n. nonseparation of paired chromosomes during cell division (Biology) …   English contemporary dictionary

• nondisjunction — /nɒndɪsˈdʒʌŋkʃən/ (say nondis jungkshuhn) noun the failure of chromosomes to follow normal separation into daughter cells at division …  

• Meiotic nondisjunction — Failure of two members of a chromosome pair to separate (disjoin) during meiosis so that both go to one daughter cell and none to the other. This mechanism is responsible for the extra chromosome 21 in trisomy 21 (Down syndrome) and for extra and …   Medical dictionary