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1.
着丝粒是真核染色体上的重要细胞器,是真核染色体作为基因载体行使其遗传功能的关键结构.着丝粒DNA首先是从酵母中分离克隆并被用以构建酵母人工染色体.鉴于真核有丝分裂机制研究和构建高等动物人工染色体研究的需要,从分离和检定过的小鼠着丝粒DNA库中筛选出了6#着丝粒DNA(SFADNA),并用荧光原位杂交法(FISH)对其进行了在染色体上的定位检定.用缺口平移法和PCR法分别标记了SFA DNA和SFA DNA中的小鼠寡份卫星DNA作为探针,分别与小鼠腹水癌细胞和小鼠L929细胞进行原位杂交;并用荧光抗体显示杂交信号的位置.结果,SFA DNA在两种细胞的中期染色体上的杂交信号都位于亚末端的初级缢痕处,表现为单一粗大的斑块.寡份卫星DNA在两种细胞的中期染色体上的杂交信号亦都位于亚末端的初级缢痕处,但极大多数的斑点均表现为成对的细小斑点.初级缢痕正是染色体着丝粒所在的特征性部位.故以上结果说明定位于该部位的克隆的6#SFA DNA,和其中的小鼠寡份卫星DNA都来源于小鼠着丝粒DNA.  相似文献   

2.
通过荧光原位杂交(FISH)利用来源于A基因组栽培稻的中高度重复序列C0t-1DNA和基因组DNA作为探针,对栽培稻、斑点野生稻和短药野生稻进行了比较基因组分析。结果发现C0t-1DNA杂交信号主要分布在这3种染色体的着丝粒、近着丝粒和端粒区域,在斑点野生稻染色体上的信号多于短药野生稻,与gDNA作为探针FISH的结果相一致,说明A和B基因组间的亲缘关系明显近于A和F基因组。确定了含有中高度重复序列的C0t-1DNA用于属内种间关系研究的可行性,并根据C0t-1DNA的FISH结果进行了染色体核型分析。  相似文献   

3.
吴绮  覃瑞  李刚  刘虹 《植物科学学报》2010,28(6):654-659
利用AA染色体组栽培稻的中高度重复序列C0t-1 DNA和基因组DNA作为探针,通过荧光原位杂交技术对宽叶野生稻(Oryza latifolia)(CCDD染色体组)进行了比较基因组分析。结果显示,在宽叶野生稻染色体上,C0t-1 DNA的杂交信号没有基因组DNA的杂交信号明显;杂交信号主要分布在着丝粒、近着丝粒及端粒区域;随着洗脱严谨度的不同,杂交信号呈现出较高的种特异性。本研究以不同洗脱严谨度下的荧光原位杂交结果为依据,对宽叶野生稻进行的核型分析,可进一步提高稻属染色体识别的准确性。  相似文献   

4.
着丝粒是真核染色体上的重要细胞器,是真核染色体作为基因载体行使其遗传功能的关键结构。着丝粒DNA首先是从酵母中分离克隆并被用以构建酵母人工染色体。鉴于真核有丝分裂机制研究和构建高等动物人工染色体研究的需要,从分离和检定过的小鼠着丝粒DNA库中筛选出6#着丝粒DNA(SAF DNA),并用荧光原位杂交法(FISH)对其进行了在染色体上的定位检定。用缺口平移法和PCR法分别标记了SFA DNA和SFA DNA中的小鼠寡份卫星DNA作为探针,分别与小鼠腹水癌细胞和小鼠929细胞进行原位杂交;并用荧光抗体显示杂交信号的位置。结果:SFA DNA在两种细胞的中期染色体上的杂交信号都位于亚末端的初级缢痕处,表现为单一粗大的斑块。寡份卫星DNA在两种细胞的中期染色体上的杂交信号亦都位于亚末端的初级缢痕处,但极大多数的斑点均表现为成对的细小斑点。初级缢痕正是染色体着丝粒所在的物征性部位。故以上结果说明定位于该部位的克隆的6#SFA DNA,和其中的小鼠寡份卫星DNA都来源于小鼠着丝粒DNA。  相似文献   

5.
利用AA染色体组栽培稻的中高度重复序列C0t-1 DNA和基因组DNA作为探针,通过荧光原位杂交技术对宽叶野生稻(Oryza latifolia)(CCDD染色体组)进行了比较基因组分析。结果显示,在宽叶野生稻染色体上,C0t-1 DNA的杂交信号没有基因组DNA的杂交信号明显;杂交信号主要分布在着丝粒、近着丝粒及端粒区域;随着洗脱严谨度的不同,杂交信号呈现出较高的种特异性。本研究以不同洗脱严谨度下的荧光原位杂交结果为依据,对宽叶野生稻进行的核型分析,可进一步提高稻属染色体识别的准确性。  相似文献   

6.
本工作用Hoechst 33258及着丝粒特异抗体间接免疫荧光法显示的小鼠粗线期染色体主缢痕区,与以小鼠富集着丝粒(SFA)DNA为探针在粗线期染色体上的原位杂交主缢痕区作了比较。发现SFA DNA探针不仅杂交于全部常染色体联会复合体上的着丝粒区,并且杂交于着丝粒周围的异染色质区;而且,也杂交于X,Y染色体的着丝粒区。由此结论:此富集SFA DNA中含有全套常染色体及X,Y染色体的SFA DNA。  相似文献   

7.
采用生物素标记的拟南芥基因组DNA探针在75%杂交严谨度下对双子叶植物番茄、蚕豆和单子叶植物水稻、玉米、大麦的染色体进行了比较基因组荧光原位杂交(comparative genomic in situ hybridization,cGISH)分析,以揭示拟南芥与远缘植物基因组间的同源性.cGISH信号代表了拟南芥基因组DNA中的重复DNA与靶物种染色体上同源序列的杂交.探针DNA在所有靶物种的全部染色体上都产生了杂交信号.杂交信号为散在分布,并呈现随基因组增大,杂交信号增多,且分布更加分散的趋势.所有靶物种的核仁组织区(NOR)都显示了明显强于其他区域的杂交信号,表明拟南芥基因组DNA探针可用于植物NOR的物理定位.在所有的靶物种中,信号主要分布在染色体的臂中间区和末端,着丝粒或近着丝粒区有少数信号分布.大麦染色体显示了与C-和N-带不同的独特的cGISH信号带型,表明此探针可用于不同植物染色体的识别.这些结果表明,拟南芥基因组与远缘植物基因组之间,除rDNA和端粒重复序列外,还存在其它同源的重复DNA;一些重复DNA序列在被子植物分歧进化为单子叶和双子叶植物之前就已存在,虽经历了长期的进化过程,至今在远缘物种之间仍保持了较高的同源性.结果还提示,大基因组中古老而保守的重复DNA在进化过程中发生了明显的扩增.  相似文献   

8.
重复DNA沿染色体的分布是认识植物基因组的组织和进化的要素之一。本研究采用一种改良的基因组原位杂交程序,对基因组大小和重复DNA数量不同的6种植物进行了自身基因组原位杂交(self-genomic in situ hybridization,self-GISH)。在所有供试物种的染色体都观察到荧光标记探针DNA的不均匀分布。杂交信号图型在物种间有明显的差异,并与基因组的大小相关。小基因组拟南芥的染色体几乎只有近着丝粒区和核仁组织区被标记。基因组相对较小的水稻、高粱、甘蓝的杂交信号分散分布在染色体的全长,但在近着丝粒区或近端区以及某些异染色质臂的分布明显占优势。大基因组的玉米和大麦的所有染色体都被密集地标记,并在染色体全长显示出强标记区与弱标记或不标记区的交替排列。此外,甘蓝染色体的所有近着丝粒区和核仁组织区、大麦染色体的所有近着丝粒区和某些臂中间区还显示了增强的信号带。大麦增强的信号带带型与其N-带带型一致。水稻自身基因组原位杂交图型与水稻Cot-1DNA在水稻染色体上的荧光原位杂交图型基本一致。研究结果表明,自身基因组原位杂交信号实际上反映了基因组重复DNA序列对染色体的杂交,因而自身基因组原位杂交技术是显示植物基因组中重复DNA聚集区在染色体上的分布以及与重复DNA相关联的染色质分化的有效方法。  相似文献   

9.
佘朝文  蒋向辉  宋运淳  刘伟 《遗传》2010,32(3):264-270
为分析玉米着丝粒卫星DNA(CentC)和着丝粒反转录转座子(CRM)在玉米种的亚种及近缘种中的保守性,采用双色荧光原位杂交检测了这两种重复序列在墨西哥玉米、二倍体多年生类玉米、多年生类玉米、摩擦禾、薏苡、高粱中的存在和分布。CentC、CRM探针在墨西哥玉米、二倍体多年生类玉米和多年生类玉米的所有染色体的着丝粒区产生了强或较强的杂交信号, 而且不同染色体的杂交信号的强度存在差异, 表明两种玉米着丝粒重复序列在不同着丝粒中的数量不同; 此外, 部分着丝粒中的CentC和CRM信号的强度存在差异, 不完全重叠。CentC、CRM探针仅在摩擦禾的多数染色体的着丝粒区产生了弱的杂交信号。在薏苡和高粱中仅测检到主要分布在着丝粒区的较强或强的CRM信号。这些结果表明, CentC在玉米种的亚种间及玉蜀黍属的物种间高度保守, 在与玉蜀黍属亲缘关系最近的摩擦禾属物种中也具有较高的保守性; CRM在与玉蜀黍属亲缘关系较近和较远的禾本科种属中都具有保守性。  相似文献   

10.
目的:探讨高特异性HER2/CEP17双色探针在浸润性乳腺癌中的诊断价值。方法:制备高特异性HER2/CEP17双色探针,通过外周血细胞核型滴片检测该探针的特异性,同时用传统探针和新制备探针对425例浸润性乳腺癌患者进行FISH检测,并对结果进行对比分析,评估高特异性HER2/CEP17探针在浸润性乳腺癌中的临床诊断价值。结果:染色体定位显示,传统的CEP17探针在17号染色体着丝粒处杂交信号明亮,在Y染色体着丝粒处可见一个较17号染色体略弱但肉眼可辨的杂交信号点;而新制备CEP17探针在17号染色体着丝粒处具有明亮的杂交信号,在其余染色体中未见明显的杂交信号点,表明该探针具有较高的特异性。临床样本检测中,新制备探针与传统探针对浸润性乳腺癌HER2基因扩增的检测无统计学差异(P=0.500,χ~2=0.5),然而,对于CEP17杂信号,统计结果表明新制备探针明显少于传统探针(P=0.013,χ~2=5.29)。结论:新方法制备HER2/CEP17探针具有较高的特异性,相比于传统探针更具有临床应用优势。  相似文献   

11.
Summary Genomic in situ hybridization was used to identify alien chromatin in chromosome spreads of wheat, Triticum aestivum L., lines incorporating chromosomes from Leymus multicaulis (Kar. and Kir.) Tzvelev and Thinopyrum bessarabicum (Savul. and Rayss) Löve, and chromosome arms from Hordeum chilense Roem. and Schult, H. vulgare L. and Secale cereale L. Total genomic DNA from the introgressed alien species was used as a probe, together with excess amounts of unlabelled blocking DNA from wheat, for DNA:DNA in-situ hybridization. The method labelled the alien chromatin yellow-green, while the wheat chromosomes showed only the orange-red fluorescence of the DNA counterstain. Nuclei were screened from seedling root-tips (including those from half-grains) and anther wall tissue. The genomic probing method identified alien chromosomes and chromosome arms and allowed counting in nuclei at all stages of the cell cycle, so complete metaphases were not needed. At prophase or interphase, two labelled domains were visible in most nuclei from disomic lines, while only one labelled domain was visible in monosomic lines. At metaphase, direct visualization of the morphology of the alien chromosome or chromosome segment was possible and allowed identification of the relationship of the alien chromatin to the wheat chromosomes. The genomic in-situ hybridization method is fast, sensitive, accurate and informative. Hence it is likely to be of great value for both cytogenetic analysis and in plant breeding programmes.  相似文献   

12.
The structure and variation of nuclear ribosomal DNA (rDNA) units of Picea abies, (L.) Karst. was studied by restriction mapping and Southern hybridization. Conspicuous length variation was found in the internal transcribed spacer (ITS) region of P. abies, although the length of this region is highly conserved both within and among most of the plant species. Two types of ITS variants (A and B), displaying a size difference of 0.5 kb in the ITS2 region, were present within individuals of P. abies from Sweden, Central Europe and Siberia. A preliminary survey of 14 additional Eurasian and North American species of Picea suggested that length variation in the ITS region is widespread in this genus. Alltogether three length variants (A, B and C) were identified. Within individuals of eight Picea species, two length variants were present within the genome (combinations of A and B variants in P. glehnii, P. maximowiczii, P. omorika, P. polita and P. sitchensis and variants B and C in P. jezoensis, P. likiangensis and P. spinulosa). Within individuals from five species, however only one rDNA variant was present in their genome (variant A in P. aurantiaca, P. engelmannii, P. glauca, P. koraiensis and P. koyamai; variant B in P. bicolor). The ITS length variation will be useful as a molecular marker in evolutionary studies of the Picea species complex, whose phylogeny is controversial. The presence of intraindividual variation in, and shared polymorphism of the, ITS length variants raises questions about the occurrence of interspecific hybridization during the evolutionary history of Picea.  相似文献   

13.
A two year-old child presented with mild developmental delay. On karyotype analysis, a supernumerary small marker chromosome (SMC) was found in all cells examined. This SMC was approximately the size of an isochromosome 18p, being symmetrical with a central constriction. C-banding and silver staining were negative and FISH with all chromosome-specific paints, centromere probes and telomere probes showed no hybridization to the SMC; telomere repeat sequences were however present on both arms. Comparative genomic hybridization showed no amplification of any chromosome region. Flow sorting of the SMC and reverse painting onto normal metaphase spreads showed no hybridization to any chromosome, whereas reverse painting onto the patient's own metaphases showed hybridization to the SMC only. This SMC may thus represent either a complex amplicon of different genomic regions, or a multifold amplification of a very small region, with a neocentromere comprising an active kinetochore but no alphoid DNA. Prognostic implications for the proband were difficult to assess due to the absence of reports of similar marker chromosomes in the literature.  相似文献   

14.
A detailed karyotype analysis was made on the somatic complement ofPicea rubens andP. glauca. B-chromosomes were observed in someP. glauca populations. The karyotypes are generally asymmetrical with most of the chromosomes having median to median-submedian centromeres.Picea glauca chromosomes 2, 3, 7, and 8 have secondary constriction on their short arm and chromosome 10 has a secondary constriction on the long arm. Chromosome 3 was the most easily identifiable, as it has two secondary constrictions located on the short arm. InP. rubens, all the chromosomes but chromosomes 8 and 9 have one to four distinctive secondary constrictions. In general, the diagrammatic comparisons show a high degree of similarity amongP. mariana, P. rubens, andP. glauca. GenomicP. mariana probe strongly hybridized to dots of genomic DNA fromP. rubens andP. glauca indicating that there is a high sequence homology among these three species. The synchronizing agent, hydroxyurea was used at different concentrations to enhance the mitotic index of cell suspensions derived from embryogenic cultures. Hydroxyurea at 1.25 mM increased significantly the mitotic index. An increase of hydroxyurea from 1.25 mM to 5 mM and 10 mM resulted in a steady decrease of mitotic index.  相似文献   

15.
Wang J  Xiang F  Xia G 《Planta》2005,221(2):277-286
The introgressed small-chromosome segment of Agropyron elongatum (Host.) Neviski (Thinopyrum ponticum Podp.) in F5 line II-1-3 of somatic hybrid between common wheat (Triticum aestivum L.) and A. elongatum was localized by sequential fluorescence in situ hybridization (FISH), genomic in situ hybridization (GISH) and karyotype data. Karyotype analysis offered basic data of arm ratios and relative lengths of 21 pairs of chromosomes in parent wheat Jinan177 and hybrid II-1–3. Using special high repetitive sequences pSc119.2 and pAs1 for FISH, the entire B- and D-genome chromosomes were detected. The FISH pattern of hybrid II-1-3 was the same as that of parent wheat. GISH using whole genomic DNA from A. elongatum as probe determined the alien chromatin. Sequential GISH and FISH, in combination with some of the karyotype data, localized the small chromosome segments of A. elongatum on the specific sites of wheat chromosomes 2AL, 1BL, 5BS, 1DL, 2DL and 6DS. FISH with probe OPF-031296 from randomly amplified polymorphic DNA (RAPD) detected E-genome chromatin of A. elongatum, which existed in all of the small chromosome segments introgressed. Microsatellite primers characteristic for the chromosome arms above were used to check the localization and reveal the genetic identity. These methods are complementary and provide comprehensive information about the genomic constitution of the hybrid. The relationship between hybrid traits and alien chromatin was discussed.  相似文献   

16.
Leaf traits and physiology are species-specific and various with canopy position and leaf age. Leaf photosynthesis, morphology and chemistry in the upper and lower canopy positions of Pinus koraiensis Sieb. et Zucc and Quercus mongolica Fisch. ex Turoz in broadleaved Korean pine forest were determined in September 2009. Canopy position did not significantly affect light-saturated photosynthetic rate based on unit area (P area) and unit dry mass (P mass), apparent quantum yield (α), light compensation point (LCP), light saturation point (LSP); total nitrogen (Nm), phosphorus (Pm), carbon (Cm), and chlorophyll content (Chlm) per unit dry mass; leaf dry mass per unit area (LMA) and photosynthetic nitrogen-use efficiency (PNUE) for P. koraiensis current-year needles and Q. mongolica leaves. While in P. koraiensis one-year-old needles, P area, P mass, α and LCP in the upper canopy were lower than those in the lower canopy. The needles of P. koraiensis had higher Cm and LMA than leaves of Q. mongolica, but P mass, Chlm and PNUE showed opposite trend. There were no differences in P area, LSP, Nm, and Pm between the two species. Needle age significantly influenced photosynthetic parameters, chemistry and LMA of P. koraiensis needles except LCP, LSP and Cm. In contrast to LMA, P area, P mass, Nm, Pm, Chlm, and PNUE of one-year-old needles were significantly lower than those of current-year needles for P. koraiensis. The negative correlations between LMA and P mass, Nm, Pm, Chlm, and positive correlations between P mass and Nm, Pm, Chlm were found for P. koraiensis current-year needles and Q. mongolica leaves. Our results indicate that leaf nitrogen and phosphorus contents and nutrient absorption from soil are similar for mature P. koraiensis and Q. mongolica growing in the same environment, while difference in carbon content between P. koraiensis and Q. mongolica may be attributed to inherent growth characteristics.  相似文献   

17.
Two contrasting genome-specific DNA sequences were isolated from Aegilops speltoides (wild goat grass) and Hordeum chilense (wild barley), each representing more than 1 % of the genomes. These repetitive DNA fragments were identified as being genome-specific before cloning by genomic Southern hybridization (using total genomic DNA as a probe), and hence extensive screening of clones was not required. For each fragment, up to six recombinant plasmid clones were screened and about half were genome-specific. Clone pAesKB52 from Ae. speltoides was a 763 by EcoRI fragment, physically organized in simple tandem repeats and shown to localize to sub-telomerec chromosome regions of species with the Triticeae S-genome by in situ hybridization to chromosomes. The sequence data showed an internal duplication of some 280 bp, which presumably occurred before sequence amplification and dispersion, perhaps by unequal crossing-over or reciprocal translocation. In situ hybridization showed that the sequence distribution varied between closely related (S-genome) species. Clone pHcKB6 was a 339 by DraI fragment from H. chilense, also tandemly repeated but more variable; loss of the DraI site resulting in a ladder pattern in Southern blots which had little background smear. In situ hybridization showed that the tandem repeats were present as small clusters dispersed along all chromosome arms except at a few discrete regions including the centromeres and telomeres. The clone hybridized essentially specifically to the H-genome of H. chilense and hence was able to identify the origin of chromosomes in a H. chilense x Secale africanum hybrid by in situ hybridization. It has a high A + T content (66%), small internal duplications, and a 50 by degenerate inverted repeat. We speculate that it has dispersed by retrotransposition in association with other sequences carrying coding domains. The organization and evolution of such sequences are important in understanding long-range genome organization and the types of change that can occur on evolutionary and plant breeding timescales. Genome-specific sequences are also useful as markers for alien chromatin in plant breeding.  相似文献   

18.
A species-specific repetitive DNA fragment has been isolated from a genomic library of Solanum brevidens. Sequence analysis revealed a regular organization of three non-homologous subrepeats forming tandemly-arranged composite repetitive units. Interpretation of Southern hybridization patterns based on the known sequence data suggests that the isolated sequence element represents an abundant organization type, although the presence of simple tandem arrays of the subrepeats is also indicated. Seventy-four percent sequence similarity was found between one of the S. brevidens subrepeats (Sb4AX) and a satellite DNA (TGRI) localized as a subtelomeric repeat on almost all Lycopersicon esculentum chromosomes. Insitu hybridization indicated that, similarly to TGRI, the S. brevidens-specific repeats are located at the ends of the arms of several chromosomes. On the basis of the data obtained, a common ancestral sequence can be proposed for the tomato (TGRI) and the S. brevidens (Sb4AX) repeat however, the molecular organization of this element in these two species evolved in a basically different manner.  相似文献   

19.
Karyotype and cytogenetic markers of Oligosarcus hepsetus from two Brazilian locations in the Paraíba do Sul River Basin (Brazil) were investigated using differential staining techniques (C-banding, silver (Ag)- and chromomycin A3 (CMA3)-staining) and fluorescent in situ hybridization (FISH) using 18 S rDNA and 5 S rDNA probes. The diploid chromosome number was invariably 2n = 50 with 3 pairs of metacentric, 5 pairs of submetacentric, 8 pairs of subtelocentric and 9 pairs of acrocentric chromosomes. No heteromorphic sex chromosomes were observed. The nucleolar organizer regions (NORs) were detected in the short arms of the largest acrocentric pair using Ag-, CMA3- stainings and FISH with 18 S rDNA probe, the latter showing also positive labeling in the short arms of a small acrocentric pair, not visualized by the former methods. FISH with 5 S rDNA probe showed positive labeling in the two chromosome pairs. While the CMA3-staining exhibited GC-rich heterochromatin segments in two pairs of chromosomes, including those coincided with Ag-NORs, the DAPI staining did not reveal any signal, indicating the absence of AT-rich heterochromatin. FISH with an As-51 satellite DNA probe derived from the closely related Astyanax scabripinnis did not reveal any positive signal, demonstrating the absence of this class of DNA in the genome of the specimens under study.  相似文献   

20.
张琦  苑丹阳  王晓春 《生态学报》2024,44(11):4876-4888
树龄是影响树木生长的最重要因素之一。在气候变暖背景下,利用树干木质部解剖特征,分析不同树龄生长-气候关系,对准确评估树木对气候变化的响应和适应策略、预测气候变化下的森林动态至关重要。利用木材解剖学方法,比较了小兴安岭溪水地区针阔混交林内大、小龄红松(Pinus koraiensis)木质部解剖特征及其对气候变化的响应异同。结果表明:大龄红松主要管胞特征值随年龄增加而呈上升趋势,但小龄红松的变化趋势并不明显,两者均在1840-1890年和1980-2010年间出现剧烈的波动。大、小年龄红松部分管胞特征与气候因子的关系具有一致性,管胞数量和理论导水率分别与月最高温度负相关和正相关;总管胞面积(负相关)、理论导水率(正相关)、平均水力直径(正相关)与月最低温度的关系一致;理论导水率与月总降水正相关;管胞占比、平均管胞面积、理论导水率、平均水力直径均与平均相对湿度正相关,且大龄红松相关性更强。大、小年龄红松管胞特征与气候因子的关系的不一致表现在,大龄红松管胞占比、平均管胞面积、总管胞面积和平均水力直径与月最高温度正相关,而这些关系在小龄红松则表现为负相关。大龄红松管胞数量与7-9月最低温度正相关,而在小龄红松表现为显著负相关;大、小龄红松除理论导水率外其他管胞特征与降水关系基本相反,其中管胞数量的相关性更强;大龄红松与7月、9月、年总降水量显著正相关,而小龄红松与6月和年总降水显著负相关;与月平均相对湿度的相关关系大龄红松表现为正相关或不显著,而小龄红松呈负相关关系。温度是限制大、小龄红松管胞特征生长的主要气候因子,降水的影响相对较弱,平均相对湿度对大小龄红松的影响差异不大。近几十年,小兴安岭地区气候暖干化趋势逐渐增强,这种暖干化会造成大、小龄红松生长的响应差异。若气候持续变暖或加剧,小龄红松会出现严重生长衰退。  相似文献   

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