单词 | b chromosome |
释义 | > as lemmasB chromosome B chromosome n. Genetics (a) a chromosome reckoned as the second in various classifications; now disused; (b) a small extra chromosome, found esp. in plants and invertebrates, which has no equivalent in the basic chromosome set of a species, and has an irregular, non-Mendelian, mode of inheritance. ΚΠ 1909 Amer. Naturalist 43 243 For each pair in the cells of a given individual there is a homologous pair in the cells of other individuals of the species.... We may designate one of these pairs as A chromosomes, a second as B chromosomes, etc., the same pairs as a rule being found in different individuals of the same species. 1927 Amer. Jrnl. Bot. 14 80 The A-chromosomes are shown in this nucleus in the lower part of fig. 15. The second large pair (B-chromosomes) are represented in figure 20. 1928 L. F. Randolph in Anat. Rec. 41 102 In maize have been found supernumerary chromosomes of three types:... b) Chromosomes of approximately the same size as the smallest members of the typical set, but differing from them in form and behavior... Type-B chromosomes are present in many commercial varieties and genetical cultures.] 1941 Genetics 26 608 Among 440 plants of these varieties of Indian maize, there were 63 with one or more B chromosomes. 1983 J. R. S. Fincham Genetics vi. 167 With the exception of those occasional ‘optimal extras’ the B-chromosomes.., all chromosomes seem to have unique and essential functions. 2005 F. P.-M. de Villena in A. Ruvinsky & J. A. M. Graves Mammalian Genomics xiii. 321/2 B chromosomes are comparatively rare among mammals. < as lemmas |
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