| 释义 |
diploid, n. and a.|ˈdɪplɔɪd|
[f. Gr. διπλό-ος double + εἶδος form.]
A. n.
a. Cryst. A solid belonging to the isometric system, contained within twenty-four trapezoidal planes; = diplohedron.
b. Biol. A diploid organism.
B. adj. Biol. [a. G. diploid (E. Strasburger 1905, in Jahrb. f. wissensch. Bot. XLII. 62): see -ploid.]Of a cell or its nucleus: having two homologous sets of chromosomes, one from each parent, each containing the haploid number of chromosomes; also, of or pertaining to diploidy, (of an organism) having somatic cells that are diploid. Hence ˈdiploidy, the condition of being diploid; ˌdiploidiˈzation; ˈdiploidize v. trans. (see quot. 1930).
1908[see haploid a.]. 1914G. N. Calkins Biol. ix. 209 Each has the number of chromosomes characteristic of the species (in modern terminology the diploid number). 1924E. W. Macbride Study Heredity viii. 216 Other examples of such ‘tetraploidy’ (i.e. doubling the ordinary ‘diploid’ number of chromosomes) are known to occur amongst the progeny of hybrids between different species. 1928Amer. Naturalist LXII. 57 Stronger evidence for diploidy of biparental males appears when three character differences, all affecting one structure, the wing, are involved. 1930A. H. R. Buller in Nature 1 Nov. 687/1 The term diploidisation has been introduced here for the first time to designate the process by which a haploid cell is converted into a diploid cell or a haploid mycelium into a diploid mycelium by the formation of conjugate nuclei within the cell's or the mycelium's interior. A haploid mycelium of one sex may be said to diploidise a haploid mycelium of opposite sex. 1952New Biol. XIII. 31 Most animals and many flowering plants are diploids. 1955Sci. Amer. June 56/3 The body cells of a normal salamander are diploid. 1957Encycl. Brit. XI. 486 Forty-eight is the diploid chromosome number in man... Haploid cells arise from diploid ones by a complex process known as meiosis. 1957[see haploid a.]. 1964G. H. Haggis et. al. Introd. Molecular Biol. x. 277 It is possible by exploiting a special phenomenon, known as sexduction, to bring about a stable state of diploidy for a short length of the chromosome. 1968[see haploid a.]. 1971Nature 7 May 49/2 If a diploid spermatozoon fertilizes a normal ovum, the resulting zygote would be triploid. |