Between rat and mouse zoo-FISH reveals 49 chromosomal segments that have been conserved in evolution

Mouse single chromosome paints were applied to rat prophase/prometaphase chromosomes to detect homologous chromosome regions. The analysis revealed 49 rat chromosomal regions ranging in size from whole chromosomes down to small bands near the limit of detection with this method, which was estimated to be 2-3 Mb. When all the painted regions were taken into account, the whole rat genome was covered with mouse-homologous regions, with the exception of small segments near the centromeres and the short arms of Chromosomes (Chrs) 3, 11, 12, and 13. These regions were shown to contain high levels of rat-specific repetitive DNA. The number of conserved segments between rat and mouse detected by our high-resolution zoo-FISH method was significantly higher than that reported in previous studies.     

Chromosome ideograms of the laboratory rat (Rattus norvegicus) based on high-resolution banding, and anchoring of the cytogenetic map to the DNA sequence by FISH in sample chromosomes

A detailed banded ideogram representation of the rat chromosomes was constructed based on actual G-banded prometaphase chromosomes. The approach yielded 535 individual bands, a significant increase compared to previously presented ideograms. The new ideogram was adapted to the existing band nomenclature. The gene locus positions in the rat draft DNA sequence were compared to the chromosomal positions as determined by dual-color FISH, using rat (RNO) chromosomes 6 and 15 and a segment of RNO4 as sample regions. It was found that there was generally an excellent correlation in the chromosome regions tested between the relative gene position in the DNA molecules and the sub-chromosomal localization by FISH and subsequent information transfer on ideograms from measurements of chromosomal images. However, in the metacentric chromosome (RNO15), the correlation was much better in the short arm than in the long arm, suggesting that the centromeric region may distort the linear relationship between the chromosomal image and the corresponding DNA molecule.     

Karyotypes and Giemsa C-banding patterns of Zebrina pendula, Z. purpusii and Setcreasea purpurea, compared with those of Tradescantia ohiensis.

It has been proposed that the genera Zebrina and Setcreasea of the family Commelinaceae should be united and reunited, respectively, with the genus Tradescantia, mainly based on morphological studies. In the present study, karyotypes and Giemsa C-banding patterns in the root-tip cells of three Zebrina and two Setcreasea clones were analyzed, and were compared with those of a triploid Tradescantia clone. Z. pendula and Z. purpusii (both 2n = 24) were found to have similar karyotypes (4 M + 6 ST + 14 T; M = meta-, ST = subtelo-, T = telocentric chromosomes), while Z. pendula cv Quadricolor (2n = 23) had a unique karyotype (6 M + 5 ST + 11 T + 1 SA; SA = short acrocentric chromosome). The only clear difference between Z. pendula and Z. purpusii was that one and two subtelocentric chromosomes, respectively, had satellites at the short arms. Two clones of S. purpurea (2n = 24) had karyotypes (8 M + 8 M' + 8 SM; M' = nearly meta-, SM = submetacentric chromosomes) similar to each other. T. ohiensis (2n = 18) had a symmetric karyotype (9 M + 9 SM) consisting of larger chromosomes than S. purpurea. Many clear Giemsa C-bands were detected, in addition to centromeric bands in all chromosomes of all clones. Z. pendula and Z. purpusii commonly had single clear interstitial bands in eight telocentric chromosomes each, but they also had unique telomeric and other interstitial bands, respectively. Z. pendula cv Quadricolor had a unique banding pattern, i.e., satellite bands in the unique short chromosome, telomeric bands at the long arms of all metacentric chromosomes, and single interstitial bands in six telocentric chromosomes. Two clones of S. purpurea had telomeric bands at many chromosome arms and satellite bands in two nearly metacentric and one submetacentric chromosomes, but some differences were found between them. On the other hand, all the chromosomes of T. ohiensis had telomeric bands at both arms, and three submetacentric chromosomes had satellite bands. These result prove structural differentiation of chromosomes occurred among the clones, especially in Zebrina, and show that S. purpurea is relatively close to T. ohiensis, while Zebrina is obviously distant from the other two genera. Therefore, there remains a question cytologically at least for uniting Zebrina with Tradescantia.     

Characterization of G-banded chromosomes of the Indian muntjac and progression of banding patterns through different stages of condensation

Muntjac prophase and metaphase chromosomes were G-banded following methotrexate-mediated synchronization of peripheral lymphocytes. Bands and subbands were characterized from prophase through metaphase, and the progression of band patterns from late prophase to mid-metaphase was analyzed. Extended prophase chromosomes exhibited more bands and subbands, a number of which became fused with each other, giving rise to fewer and thicker bands in the condensed metaphase chromosomes. It appeared that the dark bands condensed relatively more than the light bands. Precise delineation of the bands and subbands on extended prophase chromosomes and the usage of a proposed banding pattern nomenclature should aid in better detection and localization of induced chromosomal rearrangements with this extremely useful experimental material.     

BrdU处理的鱼类染色体高分辨G-带带型分析

本文应用鱼类染色体高分辨G-带技术,重点将黄鳝培养细胞具不同长度染色体的正中期分裂相做成G-带核型加以比较分析。随着染色体长度的增加,带纹数目也增加。但增加是有限度的。染色体带纹数目的增加,明显地表现在深染带再分为若干亚带。当染色体从前期向中、后期过渡收缩变短时,一些亚带融合为原来数目的带。染色体上各个带的收缩程度、收缩时间是不均等的。实验证明大剂量的BrdU不仅能阻断鱼类细胞于中S期,也可使染色体伸长、小剂量的伸长作用不明显。最后讨论了BrdU处理与G-显带的关系、染色体带纹数目相对恒定以及染色体伸长缩短问题。     

Segmental Duplications Are Common in Rice Genome

Segmental duplications on rice (Oryza sativa L.) chromosomes 8, 9, 11, and 12 were studied by examining the distributions of sequences resolved by 13 probes detecting multiple copies of DNA sequences. Four of the hybridization bands detected by a repetitive sequence probe, rTRS, were mapped to the ends of all the four chromosomes. Two or three of the bands detected by each of the other 12 probes were also mapped to different chromosomes. The bands detected by the same probe usually occurred in similar locations of different chromosomes. Loci detected by different DNA probes were often similarly arranged on different chromosomes. Chromosomes 8 and 9 showed colinearity of marker loci arrangement indicating a possible common origin. A segment on chromosome 9 was also very similar to the previously reported duplicated fragments on the ends of chromosomes 11 and 12 which were also detected in this study, indicating a likely common origin. Moreover, the various degrees of distributional similarity of the segments suggest a complex relationship among the chromosomes in the evolution of the rice genome. These results support the proposition that chromosome duplication and diversification may be a mechanism for the origin and evolution of the chromosomes in the rice genome.     

羊驼染色体核型及其G分带的研究

为了从选种、杂交改良、疾病诊断以及性别决定的遗传机制等方面为羊驼的繁育与推广提供更为有效的细胞遗传学资料,本试验采用外周血淋巴细胞培养法及胰酶-EDTA法分析了23只胡阿基亚型羊驼（Huacaya alpaca,雌20只,雄3只）的染色体核型及其G-分带,结果表明：羊驼二倍体染色体数目为2n=74,雄性羊驼核型为74,XY;雌性羊驼核型为74,XX。其中,1～20对常染色体为亚端着丝粒染色体,21～36对常染色体为亚中着丝粒染色体和中着丝粒染色体,X为中着丝粒染色体,Y为端着丝粒染色体。G-带分析表明,羊驼G带明暗相间,显现出不同的带纹,且羊驼每对染色体都有其独特的带纹特征,其带纹数目和精细程度随着染色体长度的增加而增加。Abstract: Blood samples from 23 Huacaya alpacas, 3 males and 20 females, were used to study chromosomes and karyotypes, so as to provide some effective cytogenetic bases for the selection, improvement by crossing, disease diagnosis of alpacas, and genetic mechanisms of sex determination. Peripheral blood lymphocyte culture was used to prepare chromosome. A method of trypase-EDTA was used for G-banding. The results showed as follows: The number of diploid chromosomes was 2n=74, with the karyotype 74, XY and 74, XX for males and females respectively. Thirty-six homologous pairs of chromosomes were autosomes, in which chromosomes pairs No.1 to No.20 were acrocentric-subterminal and No.21 to No.36 metacentric-submetacentric. And X chromosome was metacentric, Y chromosome telocentric. The analysis of G-bands showed that bright and dark bands appeared by turn. It showed different bands. And every pair of chromosomes had its distinct band, and the longer the chromosomes, the more the number of bands, and the more clear the bands.     

水稻基因组中的节段重复

利用１３个多拷贝探针,研究水稻（Ｏｒｙｚａ ｓａｔｉｖａ Ｌ．）基因组第８、９、１１和１２染色体上的节段重复。由同一探针检测到的多拷贝位点通常位于不同染色体的相同部位。不同探针检测到的多拷贝位点在不同染色体上的位置顺序相同。第８种９染色体上的相同多拷贝位点的线性排列,提示这两条染色体在进行上可能来源于同一原始染色体。而第９染色体上的一个节段与前人报道的以及本研究进一步证实的第１１和第１２染色体短臂     

Methylation-sensitive restriction endonuclease digestion patterns revealed in Vicia faba L. chromosomes by in situ nick-translation

Restriction endonucleases sensitive to cytosine methylation (HpaII, MspI and HhaI) and 5-azacitidine were used to study the localization of target sequences in Vicia faba metaphase chromosomes by in situ digestion and radioactive or non-radioactive nick-translation. In control experiments, neither isolated DNA nor chromosomes in situ were digested by HpaII and MspI. Pretreatment with demethylating agent, 5-azacitidine resulted both in increased effectiveness of in situ digestion and nick-translation. In 5-azacitidine-treated material, negative bands in M chromosomes appeared. HhaI cleaved isolated DNA, digested it in situ and gave positive signals as a result of nick-translation procedure in metaphase chromosomes. In S chromosomes containing heterochromatin without target sequences for HpaII and MspI, negative bands were shown after nick-translation. Such heterochromatin contains FokI sequences and in situ nick-translation driven by that restriction enzyme resulted in positive bands.     

Simultaneous staining of sister chromatid exchanges and Q-bands in human chromosomes after treatment with methyl methane sulphonate,quinacrine mustard,and quinacrine

Summary Human peripheral lymphocyte chromosomes were stained simultaneously for sister chromatid exchanges (SCEs) and Q-banding. No effect of treatment with MMS, QM, and Q on the distribution of SCEs in chromosomes was found compared with controls. The SCEs were distributed between chromosomes roughly according to metaphase length, with the shorter chromosomes underrepresented. The majority of SCEs were located to pale bands, while a few occurred in bright bands and at interfaces between pale and bright bands. A greater frequency than expected of SCEs had occurred at identical sites in homologous chromosomes. This frequency was significantly increased after treatment with MMS.     

Localization of the gene-richest and the gene-poorest isochores in the interphase nuclei of mammals and birds

At a resolution of 850 bands, human chromosomes comprise two subsets of bands, the GC-richest H3⁺ and the GC-poorest L1⁺ bands, accounting for about 17 and 26%, respectively, of all bands. The former are a subset of the R bands and the latter are a subset of the G bands. These bands showed the highest and the lowest gene densities, respectively, as well as a number of other distinct features. Here we report that human and chicken interphase nuclei are characterized by the following features. (1) The gene-richest/GC-richest chromosomal regions are predominantly distributed in internal locations, whereas the gene-poorest/GC-poorest DNA regions are close to the nuclear envelope. (2) The interphase chromosomes seem to be characterized by a polar arrangement, because the gene-richest/GC-richest bands and the gene-poorest/GC-poorest bands are predominantly located in the distal and proximal regions, respectively, of chromosomes, and because interphase chromosomes are extremely long. While this polar arrangement is evident in the larger chromosomes, it is not displayed by the chicken microchromosomes and by some small human chromosomes, namely by chromosomes that are almost only composed by GC-rich or by GC-poor DNA. (3) The gene-richest chromosomal regions display a much more spread-out conformation compared to the gene-poorest regions in human nuclei. This finding has interesting implications for the formation of GC-rich isochores of warm-blooded vertebrates.     

Genetic map of AFLP markers in the rat (Rattus norvegicus) derived from the H x B/Ipcv and B x H/Cub sets of recombinant inbred strains

The amplified fragment length polymorphism (AFLP) technique has been used to enhance marker density in a large set of recombinant inbred strains (H × B and B × H) derived from a spontaneously hypertensive rat (SHR/OlaIpcv) and a Brown-Norway (BN.lx/Cub) inbred strain. Thirteen different primer combinations were tested and a total of 191 polymorphic bands were detected. From these polymorphic bands 89 AFLP markers could be assigned to specific chromosomes. Several of these AFLP markers were mapped to regions with low marker density, thus filling up gaps in the existing genetic map of these recombinant inbred strains. These results substantiate the value of the AFLP technology in increasing marker density in genetic maps.     

AluI and HaeIII restriction enzyme banding patterns of Macaca fuscata and Cercopithecus aethiops sabaeus chromosomes

AluI and HaeIII restriction endonuclease banding patterns were analyzed in Macaca fuscata and Cercopithecus aethiops sabaeus chromosomes. AluI produced C-negative bands in both species of monkeys, while HaeIII induced the appearance of C-negative bands on Macaca chromosomes and of simultaneous G + C bands on Cercopithecus metaphases.     

番茄的CPD带型和45S rDNA位点的鉴别

采用CPD（PI和DAPI组合）染色对番茄减数分裂粗线期和有丝分裂中期染色体进行了显带分析,随后用两种不同的45S rDNA克隆在相同的分裂相进行了荧光原位杂交定位分析。CPD染色在8条粗线期染色体上显示出了10条红色的CPD带纹,在6对有丝分裂中期染色体上显示出了12条CPD带纹。有丝分裂中期染色体上的CPD带纹与粗线期染色体上显著的带纹具有对应性。用改良的CPD染色程序清晰而稳定地显示出这些特征性的CPD带纹为番茄的染色体,特别是有丝分裂中期染色体提供了新的识别标记。用番茄的一个45S rDNA克隆进行的荧光原位杂交,不仅在位于2号染色体短臂的随体上显示了强的杂交信号,而且在粗线期染色体的5个CPD带区或有丝分裂中期染色体的4对CPD带区显示了弱的杂交信号。然而,用来自小麦的45S rDNA克隆pTa71进行的原位杂交却只在随体上显示了杂交信号。鉴于所用的两个45S rDNA克隆在序列上的差异,推断在番茄基因组中只有随体含有45S rDNA单位的编码区,即番茄只有一对45S rDNA位点。     

The distribution of radiation-induced breaks in the chromosomes of irradiated subjects

Distribution of radiation-induced breakpoints in chromosomes and its bands in persons recovered from acute radiation sickness and personnel from Chernobyl NPP were investigated using G-banding staining. The frequency of damaged bands and breakpoints in groups exposed to radiation was significantly higher as compared with the control group. It was shown that in exposed to radiation persons damage depends on its length. Most frequently damaged bands in the observed groups were determined. The G-negative bands and telomeres of chromosomes were more sensitive to radiation.     

Karyomorphology of six taxa in Chrysanthemum sensu lato (Anthemideae) in Egypt and their genetic relationships by Giemsa C‐banding

Abstract Giemsa C‐banding was applied to the chromosome complements of six diploid species belonging to six genera in Chrysanthemum sensu lato (Anthemideae) distributed in Egypt. Four types of C‐banding distribution were observed in the taxa as follows: (i) negative C‐banding in Anacyclus monanthos (L.) Thell.; (ii) all bands in terminal regions in Achillea fragrantissima (Forssk.) Sch. Bip, which showed 32 bands on 18 chromosomes; (iii) all eight bands at centromeric regions on eight chromosomes in Matricaria recutita L.; and (iv) bands at terminal and centromeric regions in Brocchia cinerea Vis. (12 terminal and six centromeric bands on 12 chromosomes), Cotula barbata DC. (four terminal, six centromeric, and eight short arm bands on 16 chromosomes), and Glebionis coronaria (L.) Cass. ex Spach. (eight terminal on the short arms and four large bands in centromeric regions on 12 chromosomes).     

Isozyme variations inAegilops andTriticum. III. Chromosomal basis of the esterase isozyme production in different organs of Chinese spring wheat

Developmental changes of esterase isozymes from the germination to the heading stage of normal and aneuploid lines of common wheat,Triticum aestivum cv. Chinese Spring were studied. A total of twenty major isozymes (Bands 1E to 20E) were observed, some of which were further separated to two to three closely located bands. Among these bands, 1E, 2E, 3E, 5E, 7E, 11E, 14E and 16E were found to be leaf-specific isozymes and 9E, 10E, 13E, 15E, 17E and 18E were seed-specific. Leaf-specific isozyme bands 1E, 2E and 5E are controlled by genes on three homoeologous chromosomes group 6, leaf-specific bands 7E, 11E, 14E and 16E and seed-specific bands 9E, 10E, 13E, 15E, 17E and 18E are under control of genes on homoeologous chromosomes of group 3. On the other hand, two bands, 19′E and 19″E are controlled by genes on chromosomes of homoeologous group 2 in roots of seedlings 10 days old. The present investigation showed that the genes for esterase production located on chromosome 6B had large effects in mature leaves, but chromosomes 6A and 6D had little effect on the esterase isozymes in homoeologous group 6. Genes located on chromosomes 3A, 3B and 3D have a large function in germinating seed; however, chromosomes 3B had little effect on the esterase isozymes in the mature leaf. Present findings confirmed that the chromosomes of the A, B and D genomes have different functions in the production of proteins or enzymes. Contribution from the Laboratory of Genetics, Faculty of Agriculture, Kyoto University, Japan, No. 401.     

Correlation between genetic and cytogenetic maps of the rat

To correlate rat genetic linkage maps with cytogenetic maps, we localized 25 new cosmid-derived simple sequence length polymorphism (SSLP) markers and 14 existing genetic markers on cytogenetic bands of chromosomes, using fluorescence in situ hybridization (FISH). Next, a total of 58 anchor loci, consisting of the 39 new and 19 previously reported ones, were integrated into the genetic linkage maps. Since most of the new anchor loci were developed to be localized near the terminals of the genetic or cytogenetic maps for each chromosome, the orientation and coverage of the whole genetic linkage maps were determined or confirmed with respect to the cytogenetic maps. Thus, we provide here a new base for rat genetic maps. Received: 9 September 1997 / Accepted: 11 November 1997