| 释义 |
prereˈduction Genetics.
[ad. G. praereduction (Korschelt & Heider Lehrb. der Vergleichenden Entwicklungsgeschichte der Wirbellosen Thiere (Allgemeiner Theil) (1903) II. vi. 586): see pre- A. 2 and reduction.]
a. Reduction of chromosome number at the first of the two meiotic cell divisions, rather than at the second. Opp. postreduction a.
1905Proc. Acad. Nat. Sci. Philadelphia LVII. 186 He has to assume a complex axial metamorphosis, which is wholly unnecessary on the basis of a prereduction. 1915,1921[see postreduction a].
b. Separation of homologous chromatids or genes at the first of the two meiotic cell divisions, rather than at the second. Opp. postreduction b.
1934, etc. [see postreduction b].
Hence prereˈductional a., involving or pertaining to prereduction; prereˈductionally adv.
1905Proc. Acad. Nat. Sci. Philadelphia LVII. 187 He describes a prereductional division of the bivalent chromatin nucleolus. Ibid. 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[see postreduction b]. 1950[see postreductionally adv.]. |