染色体

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。

The results in L.awera demonstrated all 10 chromosome of type I were not telocentric but acrocentric chromosome.

在1号和6号染色体上，信号位点与数量在各自的3条同源染色体间没有明显区别。5号染色体的3条染色体间的信号有明显区别，其中的2条染色体上各有1个信号，而在另一条染色体上有2个信号，但强度较弱，推测这3条同源染色体可能起源不同，或者在进化过程中发生过染色体结构变异。

The number of the chromosomes in Henan large tail sheep is 2n=54, the karyotypes of male and female sheep are 54, XY and 54, XX, respectively. There are 26 pairs of autosomes and 1 pair of sex-chromosome. Among 26 pairs of autosomes, 3 pairs are metacentric chromosomes, 23 pairs are telocentric chromosomes. X chromosome is the biggest subtelocentric chromosome and Y chromosome is the smallest submetacentric chromosome.

河南大尾寒羊二倍体染色体数目为2n=54，公羊核型54，XY；母羊核型54，XX.27对染色体中包括26对常染色体和1对性染色体，常染色体中有3对为中着丝粒染色体，23对为端着丝粒染色体；性染色体中，X染色体为最大的端着丝粒染色体，Y染色体为最小的中着丝粒染色体。

Software and results were saved in EXCEL for consequent statistic operation and obtaining chromosome patterns. 4 indexes were chose, such as chromosome karyotype, C-band pattern, chromosome behavior and B chromosome for comparative analyses, and adopted SPSS to reconstruct dendrogram. Combined with studies on insect morphology and insect geography, we made a detailed analysis and speculation on the relationship of taxa concerned. Finally we got the conclusions as follows: 1. The number of chromosomes in grasshoppers of Oedipodiae is 2n 〓=23=22+XO. All chromosomes are telocentric chromosomes. Most of the genome formulas are 3L+6M+2S+X and 3

论文选取染色体核型、C-带带型、染色体行为和B染色体这4个方面的指标进行比较分析，运用SPSS系统分析软件建立表达各属和各种之间亲缘关系的系统树，并结合昆虫形态学和昆虫地理学等方面的研究成果，对其亲缘关系进行了比较详细的分析和推测，得出以下结论：一、斑翅蝗科蝗虫的染色体数目都稳定在2n〓=23条，性别决定机制是XO型，染色体均为端部着丝粒，染色体组式以3L+6M+2S+X和3L+7M+1S+X这两种类型为主，即3对大型染色体，6～7对中型染色体和2～3对小型染色体，X染色体以中型为主，在染色体组中主要排列为4～7位。

The data show that:(1) The chromosome number of Andrias davidianus is 2n=60.(2) The karyotype consists of macrochromosomes and microchromosomes.(3) In macrochromosomes, eight pairs are metacentric and two pairs are submetacentric.(4) Andrias davidianus has 20 pairs of microchromosomes, among which are four pairs of bi-armed chromosomes. They are No.11, No.25, No.23 and No.24. Other microchromosomes are telecentric.

结果表明：(1)中国大鲵染色体数目为2n=60；(2)染色体由大染色体和微小染色体组成，属于两型性染色体；(3)大染色体中有8对中部着丝粒染色体和2对亚中部着丝粒染色体；(4)微小染色体有20对，大多是端部着丝粒染色体，在雌性中发现了4对双臂染色体，第11、25号是亚中部着丝粒染色体，第23、24号是中部着丝粒染色体。

Other three alien translocation lines referring to chromosome Lr.14 of L.racemosus were also induced via irradiated pollens.After irradiated by gamma raysof 1KR does,the pollens of T.aestivum-L.racemosus Lr.14 disomic addition lineswere used to pollinate wheat varieties"Yangmai No.5"and"Mianyang No.11".M1plants have pairing between wheat chromosomes and Lr.14 ofL.racemosus at PMCMI stage were self-pollinated,and the M2 seeds used to be Giemsa C-banded andfluorescence in situ hybridized.As the result,three alien translocation lines wereobtained and T12 was observed to have distal translocation chromosomes betweenLr.14S and a wheat chromosome segment(TW-Lr.14S·Lr.14L).T13 wasidentified to contain mostly-alien-translocation chromosome(TLr.14L·Lr.14S-W).T14 was proved to contain a translocation between Lr.14L and 6BS,with approximatebreakpoint at 6BS2.2 region, FL0.22 in the short arm of chromosome T6BL.6BS-Lr.14L.

用普通小麦-大赖草Lr.14二体异附加系经辐射处理过的花粉给扬麦5号和绵阳11号授粉，M1代植株进行PMC MI染色体配对分析和Giemsa C-分带，选出PMCMI小麦和大赖草染色体发生配对的植株进行自交，M2代经RTC M期染色体C-分带和原位杂交，鉴定出3个小麦-大赖草易位系，其中T12为由Lr.14大部分和一个小麦染色体片段组成的易位染色体(TLr.14L·Lr.14S-W)；T13含由Lr.14染色体绝大部分与小麦染色体的一个小片段组成的易位染色体(TLr.14L·Lr.14S-W)；T14易位系的染色体易位发生在小麦6BS2.2区和大赖草Lr.14L之间，易位断点在T6BL·6BS-Lr.14L易位染色体的FL0.22附近。

The results showed that karyotypic type of Ya01-21was 2n=104＝100m+4sm（4SAT）, Chromosome length ratio of the longest and the shortest 4.25, the average arm-ratio 1.35, belonging to 2C type of chromosome. Molecule identified combine with chromosome studied indicated that Ya01-21 was a progenies of Erianthus arundinaceum. following the law of n+n; ITS identify showed that Ya01-21 is a progenies of Erianthus arundinaceum, the somatic chromosome karyotypic type of Ya01-36 was 2n=132＝130m+2sm, Chromosome length ratio of the longest and the shortest 3.94, the average arm-ratio 1.27, belonging to 2B type of chromosome, combining the advance of characters the law of 2n+n can be resumed.

研究结果表明，崖城01－21的体细胞染色体核型公式为2n＝104＝100m+4sm（4SAT），最长与最短染色体的长度比为4.25，平均臂比1.35，染色体属2C型，分子鉴定结合细胞学研究认为其为斑茅的真实后代，其染色体遗传为n+n；崖城01－36经ITS签定为真实杂种，其体细胞染色体核型公式为2n＝132＝130m+2sm，最长与最短染色体的长度比为3.94，平均臂比1.27，染色体属2B型，结合其性状的进展，推断亲本向其传递染色体可能以2n+n的方式进行。

Compared the similarity and difference of distribution of homologous fragments on X and Y, we suggested that the sex chromosomes of spiny eel have evolved from a pair of homologous ancestral chromosomes, and during the evolution, a pericentric inversion might have occurred on the original Y chromosome, and subsequently terminal regional duplication might have followed, eventually resulting in the differentiation and formation of X and Y chromosomes, then the recombinants between sex chromosomes were repressed, so the sex chromosomes could be inherited steadily.

根据X、Y染色体上同源片段的分布的相似和相异，我们对刺鳅性染色体的分化历程进行了推测，即：刺鳅的性染色体起源于一对原始的同源染色体，通过原Y染色体上的一个明显的臂间倒位，以及染色体末端的异染色质成分的扩增，导致原始Y染色体与X染色体在染色体结构上的分化，从而抑制了X、Y性染色体之间的遗传物质的重组交换，为性染色体的稳定遗传奠定了基础。

The results are as follow:The diploid chromosome number of Taihe Silkies was 2n=78,the basic number of chromosome arms was AF=90 and the sex chromosome type was ZZ/ZW.According to the measured relative length,arm ratio and centromeric index,the first 10 pairs of macro-chromosomes are described as follows:No.1 ,9 and Z,W chromosomes were metacentrics,No.2,4,7 were submetacentrics,and No.3,6,8,10 were telocentrics.Studies on Taihe Silkies′ G-band showed that the first 10 pairs of macro-chromosomes can be divided into 29 zones and 190 bands.

结果表明：泰和乌骨鸡体细胞染色体数目2n=78，染色体基本臂数AF=90，1、9号染色体及Z、W性染色体为中央着丝粒染色体，2、4、7号染色体为亚中央着丝粒染色体，3、6、8、10号染色体为端着丝粒染色体。G带研究表明：前10对大型染色体可分为29个区，190条带。C带处理发现，所有母鸡分裂相中W性染色体都出现C带并整条深染。

State University and the Chemical (Genomics 染色体组的)Center at N.I.

化学染色体中心的科学家在自然药物期刊上报道了这个发现。

In the United States, chronic alcoholism and hepatitis C are the most common ones.

在美国，慢性酒精中毒，肝炎是最常见的。

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如果有任何问题，你可以随时联系我。