prereductionn.

Brit.

/ˌpriːrᵻˈdʌkʃn/, U.S.

/ˌprirəˈdəkʃ(ə)n/,

/ˌpririˈdəkʃ(ə)n/

Origin: Formed within English, by derivation; modelled on a German lexical item. Etymons: pre- prefix, reduction n.

Etymology: < pre- prefix + reduction n., after German Praereduction ( E. Korschelt& K. Heider Lehrb. der vergleichenden Entwicklungsgeschichte der wirbellosen Thiere (Allgemeiner Theil) (1903) II. vi. 586). Compare postreduction n.

1. Genetics.

a. The halving of the chromosome number by the separation of homologous chromosomes at the first of the two divisions of meiosis. Cf. postreduction n. 1.

ΘΚΠ

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 57 186 He has to assume a complex axial metamorphosis, which is wholly unnecessary on the basis of a prereduction.

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.

1926 Q. Rev. Biol. 1 429/2 A..review of the slides..failed to reveal any case of post-reduction of the members of the unequal pair, so..I have recorded these five instances as giving 100 per cent pre-reduction.

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.

b. Separation of the different alleles at a particular heterozygous locus in the first division of meiosis. Cf. postreduction n. 2.

ΘΚΠ

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 Let us consider only the most common bivalent type, a bivalent with prereduction in respect to centromere, and provided with one chiasma.

2004 Fungal Genetics & Biol. 41 1091/2 If a marker segregates in the first meiotic division, both nuclei of one ascospore carry the same allele (prereduction or ‘first division segregation’).

2. Prior chemical reduction.

ΚΠ

1952 Analyt. Chem. 24 761/2 (caption) Effect of solvent for prereduction upon per cent of nitrogen found.

1978 Jrnl. Assoc. Official Analyt. Chemists 61 1299 No pre-reduction of As and Se was necessary.

2005 Sci. Total Environment 339 279/1 Water samples were measured after prereduction with 3% KI and 5% ascorbic acid.

Derivatives

prereˈductional adj. Genetics involving or relating to prereduction; occurring at or relating to the first division of meiosis.

ΘΚΠ

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 describes a prereductional division of the bivalent chromatin nucleolus.

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.

prereˈductionally adv. Genetics in the manner of prereduction.

ΘΚΠ

the world > life > biology > biological processes > genetic activity > [adverb] > reduction

prereductionally1905

reductionally1905

postreductionally1950

1905 Proc. Acad. Nat. Sci. Philadelphia 57 195 Whenever the heterochromosomes occur in pairs in the spermatogonia..their univalent components become separated in the first maturation mitosis, i.e., divide prereductionally.

1950 Adv. Genetics 3 221 Certain parts of a bivalent..may separate either prereductionally or postreductionally depending on the number and position of chiasmata.

This entry has been updated (OED Third Edition, March 2007; most recently modified version published online March 2022).

单词	prereduction
释义	prereductionn. Brit. /ˌpriːrᵻˈdʌkʃn/, U.S. /ˌprirəˈdəkʃ(ə)n/, /ˌpririˈdəkʃ(ə)n/ Origin: Formed within English, by derivation; modelled on a German lexical item. Etymons: pre- prefix, reduction n. Etymology: < pre- prefix + reduction n., after German Praereduction ( E. Korschelt& K. Heider Lehrb. der vergleichenden Entwicklungsgeschichte der wirbellosen Thiere (Allgemeiner Theil) (1903) II. vi. 586). Compare postreduction n. 1. Genetics. a. The halving of the chromosome number by the separation of homologous chromosomes at the first of the two divisions of meiosis. Cf. postreduction n. 1. ΘΚΠ 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 57 186 He has to assume a complex axial metamorphosis, which is wholly unnecessary on the basis of a prereduction. 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. 1926 Q. Rev. Biol. 1 429/2 A..review of the slides..failed to reveal any case of post-reduction of the members of the unequal pair, so..I have recorded these five instances as giving 100 per cent pre-reduction. 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. b. Separation of the different alleles at a particular heterozygous locus in the first division of meiosis. Cf. postreduction n. 2. ΘΚΠ 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 Let us consider only the most common bivalent type, a bivalent with prereduction in respect to centromere, and provided with one chiasma. 2004 Fungal Genetics & Biol. 41 1091/2 If a marker segregates in the first meiotic division, both nuclei of one ascospore carry the same allele (prereduction or ‘first division segregation’). 2. Prior chemical reduction. ΚΠ 1952 Analyt. Chem. 24 761/2 (caption) Effect of solvent for prereduction upon per cent of nitrogen found. 1978 Jrnl. Assoc. Official Analyt. Chemists 61 1299 No pre-reduction of As and Se was necessary. 2005 Sci. Total Environment 339 279/1 Water samples were measured after prereduction with 3% KI and 5% ascorbic acid. Derivatives prereˈductional adj. Genetics involving or relating to prereduction; occurring at or relating to the first division of meiosis. ΘΚΠ 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 describes a prereductional division of the bivalent chromatin nucleolus. 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. prereˈductionally adv. Genetics in the manner of prereduction. ΘΚΠ the world > life > biology > biological processes > genetic activity > [adverb] > reduction prereductionally1905 reductionally1905 postreductionally1950 1905 Proc. Acad. Nat. Sci. Philadelphia 57 195 Whenever the heterochromosomes occur in pairs in the spermatogonia..their univalent components become separated in the first maturation mitosis, i.e., divide prereductionally. 1950 Adv. Genetics 3 221 Certain parts of a bivalent..may separate either prereductionally or postreductionally depending on the number and position of chiasmata. This entry has been updated (OED Third Edition, March 2007; most recently modified version published online March 2022). < n.1905
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