postreductionn.adj.
/ˈpəʊs(t)rᵻˌdʌkʃn/, U.S. /ˈpoʊs(t)rəˌdəkʃ(ə)n/, /ˈpoʊs(t)riˌdəkʃ(ə)n/ A. n. Genetics.
1. The halving of the chromosome number by the separation of homologous chromosomes at the second, rather than the first, of the two divisions of meiosis (as in certain plants and arthropods). Cf. prereduction n. 1a.
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the world > life > biology > biological processes > genetic activity > [noun] > stages of mitosis or meiosis > reduction
reduction1891
reduction division1891
pseudoreduction1899
postreduction1905
prereduction1905
1905 Proc. Acad. Nat. Sci. Philadelphia 57 188 To the idea of postreduction we can apply the criticism ‘not proven’.
1915 Jrnl. Morphol. 26 122 In regard to the question of pre- and post-reduction, I have evidence here that the first maturation division is the reduction division.
1921 L. W. Sharp Introd. Cytol. xi. 245 Such tetrads separate reductionally at the second mitosis (postreduction) rather than at the first (prereduction) in certain orthopterans.
1967 U. Mittwoch Sex Chromosomes ix. 152 The sex chromosomes of Apodemus frequently exhibit postreduction, in contrast to most other mammals in which the X- and Y-chromosome show prereduction.
2. Separation of the different alleles at a particular heterozygous locus at the second division of meiosis (as a result of the occurrence of crossing over). Cf. prereduction n. 1b.
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the world > life > biology > biological processes > genetic activity > [noun] > stages of mitosis or meiosis > separation of chromatids
metakinesis1887
postreduction1934
prereduction1934
1934 L. W. Sharp Introd. Cytol. (ed. 3) xvi. 254 Disjunction in [meiosis] I is called ‘prereduction’; that in II, ‘postreduction’.
1950 Adv. Genetics 3 221 The prereductional or postreductional division of the heterozygous allele pair depends on its situation in the bivalent. Let us consider only the most common bivalent type, a bivalent with prereduction in respect to centromere, and provided with one chiasma. (In contradistinction to this, the Lecanium species have postreduction.)
1976 Molecular & Gen. Genetics 146 101 This occurs when there is a postreduction of at least one of the genes by which the parents of the cross differ.
2004 Fungal Genetics & Biol. 41 1091/2 A crossing-over between the centromer and the marker allele leads to the generation of ascospores with nuclei which both contain a different marker allele (postreduction or ‘second division segregation’, SDS).
B. adj. Surgery and Medicine.
Occurring or carried out after a process of reduction (of a fracture, dislocation, intussusception, etc.).
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1929 Amer. Jrnl. Surg. 6 518/1 Always obtain a post-reduction roentgen-ray examination.
1953 Jrnl. Louisiana State Med. Soc. 105 474 (title) Pitfalls in the postreduction management of fractures.
1989 Lancet 1 Apr. 704/1 Postreduction roentgenograms..in congenital dislocation of the hip.
2003 Pediatrics 112 1302 (title) Postreduction management of intussusception in a children's hospital emergency department.
Derivatives
postreˈductional adj. Genetics involving or relating to postreduction; relating to or occurring at the second division of meiosis.
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the world > life > biology > biological processes > genetic activity > [adjective] > stages of mitosis or meiosis > reduction
reductional1901
postreductional1905
prereductional1905
1905 Proc. Acad. Nat. Sci. Philadelphia 57 187 He is the solitary worker on the spermatogenesis of the Hemiptera who has taken the postreductional view.
1950 Adv. Genetics 3 221 The prereductional or postreductional division of the heterozygous allele pair depends on its situation in the bivalent.
1991 Theoret. & Appl. Genetics 82 645 This precocious chromosome division may impose postreductional (SDR) or prereductional (FDR) ‘restitution’ of the sporophytic chromosome number under normal synaptic and desynaptic conditions, respectively.
postreˈductionally adv. Genetics.
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the world > life > biology > biological processes > genetic activity > [adverb] > reduction
prereductionally1905
reductionally1905
postreductionally1950
1950 Adv. Genetics 3 221 Since the number and situation of chiasmata, as a rule, varies even in the eggs of a single female, certain parts of a bivalent and consequently the gene pairs included in them may separate either prereductionally or postreductionally depending on the number and position of chiasmata.
2004 Genetica 122 199 Autosomes divide pre-reductionally while the sex chromosomes do so post-reductionally.
This entry has been updated (OED Third Edition, December 2006; most recently modified version published online March 2022).
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n.adj.1905