| 单词 | basic number |
| 释义 | > as lemmasbasic number basic number n. Genetics the haploid number of chromosomes; spec. the lowest haploid number of a polyploid series (symbol x; see X n. 3i). ΚΠ 1932 C. D. Darlington Rec. Adv. in Cytol. iii. 61 Since a zygote usually receives two similar sets of chromosomes from its two parental gametes, their number is conventionally referred to as 2n; where the chromosmomes pair regularly at meiosis they therefore form n pairs. Now in a particular individual these 2n chromosomes may consist of three sets or four sets of chromosomes relative to its own parents or ancestors. In the present work, therefore, the ‘basic number’ of this ancesteral set is distinguished by the sign x. Thus in Triticum vulgare 2n = 42 and x = 7. 1997 Ann. Missouri Bot. Garden 84 128 A literature survey was made of chromosome number counts for Rubus species. Numbers are presented for 387 species, representing about 40 percent of the total number, and including 11 of the 12 subgenera. The basic number is universally 7 and ploidy levels include 2x, 3x, 4x, 5x, 6x, 8x, 9x, 10x, 11x, 12x, 14x and questionably, 13x and 18x. < as lemmas |
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