异染色体

There was also not any haploid metaphases (n=16 or 19) was detected in hybrids. However, about 1-2% metaphases observed in this study was allopolyploid. GISH proved that they was made up of haploid genomes of M. nobilis (n=16) and triploid genomes of C. farreri (n=57). GISH was also employed to detect different chromosome components and identify donor chromatin in hybrids between C. farreri♀×A.

但我们检测到了约1-2%异源多倍体的分裂相，GISH分析后发现这些分裂相是由单倍的华贵栉孔扇贝的染色体和多倍的栉孔扇贝染色体组成，比如论文中图示了一个异源四倍体的分裂相，它是由单倍的华贵栉孔扇贝的染色体(n=16)和三倍的栉孔扇贝染色体(3n=57)组成。

Discussions are given of the fate of Ms2 during translocation in the hexoploid triticale, the exchange of the names for 4A and 4B chromosomes in common wheat and the possible expoitation of the new locus Ms2 (4BS), and the following speculations are made: In geneic genes of allopolyploid organisms the donor chromosomes tend to be intergenomically translocated to their phylogically and evolutionarily close chromosomes with the same order number and the same arm; it is cofirmed that the 7th International Conference of Wheat Genetics was right to exchange the names between chromosomes 4A and 4B of common wheat in 1988; and as a new genetic marker and a breeding tool for all the chromosome B-carrying species in the tribe of Tritceae, Ms2 (4BS) may have wide application in building and expanding the gene pool of germplasm resources of various species of wheat.

对 Ms2基因在六倍体小黑麦与原太谷核不育小麦远缘杂交中易位时的走向，普通小麦4A与4B染色体的互换更名以及 Ms2(4BS)新位点的开发利用进行了讨论：认为异源多倍体生物核基因的组间易位倾向于从供体染色体向进化亲缘关系较密切，且染色体序数与染色体臂相同的部分同源染色体易位；1988年第7届国际小麦遗传学会对普通小麦4A与4B染色体的互换更名是正确的； Ms2(4BS)作为一个新型的遗传标记，作为小麦族内所有携带B染色体组的物种的育种工具和在拓建各类小麦种质资源的基因库等方面均有广泛的用途。

The result is: out of 187 cases of azoospermia, 77(41.18%)patients with abnormal chromosome(number and structural aberration); heteromorphic chromosome(Y chromosome polymorphisms and pericentric inversion of 9) and 46,XX sex reversal. Out of 30 cases of severe oligospermia, 4 patients with abnormal chromosome(structural aberration and 46,XX sex reversal).

发现187例无精症患者中检出异常核型77例（41.18%）（其中46，XY，t(6；14)(p21；p13)，46，XY，t(8；12)(p21；q24)为世界首报核型），主要涉及染色体异常；染色体异态（Y染色体异态和9号染色体臂间倒位）及46，XX性反转；30例严重少精症患者中检出异常核型4例（13.33%）（结构异常和46，XX性反转）。

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 spiny eel , belonging to Perciformes, Osteichthyes, is a kind of little freshwater fish distributed in Southern China. In 1998, Our lab detected XX/XY differentiated sex chromosomes in this specie with karyotypic analysis, and then with chromosomal binding and SC observation, we identified that its two largest metacentric chromosomes were X, Y sex chromosomes in 1999. X, Y chromosomes differ each other not only in the distribution of heterochromatin but also in their shapes, which make them could be recognized directly under the light-microscope without any banding treatment.

刺鳅，属鲈形目、刺鳅科(Perciformes，Mastacembelidae)，是广泛分布于中国南方的小型淡水鱼类。1998年，我室通过核型分析，首次发现该物种具有明显分化的异形性染色体，其性别决定类型为XX／XY型。1999年，本室通过染色体显带、精母细胞联会复合体观察，再次确认刺鳅染色体组中最大的一对中部着丝粒染色体为X、Y性染色体，两者不仅已经出现结构异染色质分布上的不同，同时在外部形态上也存在明显差异，识别特征鲜明，在光镜观察下无需显带即能清晰辨认性染色体。

Among the fish which were cytogenetically studied, most of them do not possess any morphologically differentiated sex chromosomes. On the other hand, karyotypic analysis, chromosome binding, synaptonemal complex observation and comparative genomic hybridization show in few fish species, that there exist sex chromosomes which differentiated at different levels and types.

在进行过细胞遗传学研究的鱼类中，绝大部分没有发现异形性染色体，然而通过核型分析、染色体显带、联会复合体观察和比较基因组杂交等方法，发现在少部分鱼类中确实存在有异形分化的性染色体，并且分化程度高低不等，性别决定方式多种多样。

In the BC〓F〓 and BC〓F〓 generation of Yannong15×Thinopyron intermedium hybrid, 4 octoploids which had chromosome number of 2n=56 and could form 28 bivalent at PMC MI, 14 disomic addition lines which had chromosome number of 2n=44 and could form 22 bivalent at PMC MI; three monosomic addition lines which had chromosome number 2n=43 and had the chromosome configuration of 21Ⅱ+1Ⅰ at PMC MI, 1 substitution line which had chromosome number 2n=42 and could form 21 bivalent at PMC MI were selected by observation of mitosis in root tip cell and meiosis in pollen mother cell.

在烟农15与中间偃麦草杂交的BC〓F〓和BC〓F〓代中，通过根尖有丝分裂和花粉母细胞减数分裂中期Ⅰ观察选出4个2n=56，PMC MI染色体构型为28Ⅱ的八倍体小偃麦；14个2n=44，PMC MI染色体构型为22Ⅱ的双体异附加系；3个2n=43，PMC MI染色体构型为21Ⅱ+1Ⅰ的单体异附加系；1个2n=42，PMC MI染色体构型为21Ⅱ的异代换系。

By phenotype observation, combined with root tipchromosome counting, PMC MI pairing analysis and chromosome C-banding, a ditelosomic addition line 94K227 and a disomic addition line 94K280 was identified among BC2F2 and BC2F3 population respectively.C-banding results showed that 94K227 contains 1 pair of long arms in chromosome B, and 94K280 contains 1 pair of chromosome D from R.

用普通小麦-纤毛鹅观草双倍体与普通小麦中国春连续回交两次，然后连续自交，通过形态观察、根尖细胞染色体计数、花粉母细胞减数分裂中期Ⅰ染色体配对分析及染色体C－分带，在BC2F3和BC2F3群体中，分别筛选到一个端二体异附加系94K227和一个二体异附加系94K280，其中C-分带显示94K227添加的是纤毛鹅观草染色体B的一对长臂， 94K280添加的是纤毛鹅观草的一对染色体D。

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。

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。

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。

If you have any questions, you can contact me anytime.

如果有任何问题，你可以随时联系我。