non-disjunctionn.
/ˌnɒndɪsˈdʒʌŋ(k)ʃn/, U.S. /ˌnɑndɪsˈdʒəŋ(k)ʃ(ə)n/ 1. Genetics and Cell Biology. The failure of one or more pairs of homologous chromosomes (at meiosis) or sister chromatids (at mitosis) to separate and move away normally from the equatorial plate during nuclear division, usually with the result that one of the daughter nuclei has too few chromosomes and the other too many.
ΘΚΠ
the world > life > biology > biological processes > genetic activity > [noun] > other processes in mitosis or meiosis
zonation1899
diakinesis1902
parasynapsis1909
syndesis1909
parasyndesis1911
non-disjunction1913
non-conjunction1925
asynapsis1930
stathmokinesis1938
misdivision1939
metakinesis1948
tandem duplication1959
1913 Jrnl. Exper. Zool. 15 587 (heading) Non-disjunction of the sex chromosomes of Drosophila.
1925 Jrnl. Genetics 15 251 Non-disjunction was long ago observed in the diploid Oenothera.
1961 Lancet 5 Aug. 319/2 Mitotic nondisjunction in a normal diploid embryo could result in 1 cell with forty-eight chromosomes..and 1 non-viable cell with forty-four chromosomes.
1995 Atlantic Monthly June 62/2 Trisomies are the result of a glitch known as nondisjunction, which occurs principally during the creation of egg cells.
2. Logic. The relation of the terms in a proposition asserting the negative of a disjunctive proposition (‘neither——nor——’).
ΘΚΠ
the mind > mental capacity > philosophy > logic > predicate or propositional logic > [noun] > propositional relation > other terms relating to
domain1903
field1903
referent1903
biconditional1940
non-disjunction1949
1949 Jrnl. Symbolic Logic 14 170 x y is interpreted as (x ↓ y), in which ↓ is the joint-denial connective (likewise known as non-disjunction, ‘neither x nor y’).
1956 A. Church Introd. Math. Logic (rev. ed.) I. ii. 134 Sheffer uses the sign of disjunction, ∨, inverted as a sign of non-disjunction.
1965 G. E. Hughes & D. G. Londey Elements Formal Logic viii. 54 The following are valid: (i) (p ↑ q) ≡ ∼ (p.q), (ii) (p ↓ q) ≡ ∼ (p ∨ q), which suggests the names ‘non-conjunction’ and ‘non-disjunction’ for ‘↑’ and ‘↓’ respectively.
1974 MLN 89 915 The incorporations of the inversions and transformations..of carnival is crucial to the ambiguous complexity of the novel and to its characteristic trans-valuation of values and ‘non-disjunction’ of categories.
This entry has been updated (OED Third Edition, December 2003; most recently modified version published online March 2022).
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n.1913