减数分裂

Two signals of 45S rDNA were mapped on the mitotic metaphase chromosomes in the F1 hybrids, respectively, and one signal was present on a bivalent during meiotic of synaptene, diakinesis, and metaphase I. We inferred that the two mitotic chromosomes carrying 45S rDNA were homolo-gous pairs.

在有丝分裂中期染色体上2个杂种分别检测到2个杂交信号，在减数分裂粗线期、终变期、中期Ⅰ染色体上45S rDNA位于一个二价体上，说明这两个杂种携带45S rDNA的染色体为同源染色体。

Centromere The region of the chromosome that contains the kinetochore, the structure that becomes attached to the nuclear spindle during mitosis and meiosis.

着丝粒：染色体上包含着丝点的区域，在细胞有丝分裂和减数分裂期间与纺锤体相整合的一种结构。

Meiosis, which occurs only in the form ation of gametes, is a specialized form of cell division

仅仅发生在配子形成中的减数分裂是一种特殊形式的细胞分裂。

Chromosomes are distributed by spindles in mitosis and meiosis.

染色体是通过纺锤体的有丝分裂和减数分裂而分配的。

However, accidental changes in DNA methylation can be transmitted through mitosis or meiosis, leading to epiallelic variation.

但是，DNA甲基化的意外变化能够通过有丝分裂或减数分裂，导致表观变异。

However,the ratio ofunivalent misdivision was about 10 per cent.This wouldoffer the posibility to creat whole arm chromosometranslocation.

然而，发现在减数分裂时，单价体错分裂频率达到10%左右，为产生染色体整条臂的相互易位提供了可能。

Small cell of the mother after the cytoplasm of simultaneous type, tetrad of epidermis, mature pollen of two cell types.

小孢子母细胞减数分裂后胞质分裂为同时型，四分体为四面体型排列，成熟的花粉粒为二细胞型。

Tetraploid organisms may arise by the fusion of two diploid gametes that have resulted from the nondisjunction of chromosomes at meiosis, or by nondisjunction of the chromoosomes during the mitotic division of a zygote.

四倍体的产生可能是由于两个二倍体配子发生融合，这种二倍体配子又是在减数分裂中染色体不发生分离而形成。四倍体也可能因为受精卵进行有丝分裂时染色单体未发生分离而形成。

They are often morphologically distinct from A chromosomes, being smallerand more highly heterochromatic in most cases. B chromosomes do not pair with Achromosomes, and they are inherited in a non-Mendelian way, exhibiting meiotic andmitotic instability and nondisjunction. However, B chromosome DNA is quiteidentical to the corresponding sequence on the A chromosome complement. So far afew B chromosome specific DNA sequence have been identified. Specific DNAsequences on B chromosome have been the attractive research area on Bchromosomes.

现已在千余种植物和近三百种动物中被发现。B染色体与物种中正常染色体不同：独立于整倍体基因组之外，减数分裂时不与A染色体发生联会和配对，细胞分裂后期不分离，非孟德尔遗传，富含异染色质，不含对宿主主要性状有影响的基因等。B染色体DNA的分子组成既与A染色体极为相似，具有A染色体DNA分子组成的一般特征：富含重复序列和转座成分，染色体三大功能组件DNA高度同源；又与之相区别，含有B染色体特异的DNA序列，这些DNA序列可以为探讨B染色体的起源和进化提供有价值的信息。

As with the male gametes the remaining cytoplasma binding serves the synchronization of the division and maturation of the cells: just as for the 1rst polar body at the time of the termination of the 2nd meiosis.

和雄性配子一样，这些残留的细胞质连接有助于细胞分裂和成熟的同步化：就像第二次减数分裂结束时的第一极体一样。

However, as the name（read－only memory）implies, CD disks cannot be written onorchanged in any way.

然而，正如其名字所指出的那样，CD盘不能写，也不能用任何方式改变其内容。

Galvanizes steel pallet is mainly export which suits standard packing of European Union, the North America. galvanizes steel pallet is suitable to heavy rack. Pallet surface can design plate type, corrugated and the gap form, satisfies the different requirements.

镀锌钢托盘多用于出口，替代木托盘，免薰蒸，符合欧盟、北美各国对出口货物包装材料的法令要求；喷涂钢托盘适用于重载上货架之用，托盘表面根据需要制作成平板状、波纹状及间隔形式，满足不同的使用要求。