牛蛙染色体的高分辨晚复制带

以培养的牛蛙(Rana cataesbeiana)外周血淋巴细胞为材料,采用复制带显示技术,在牛蛙染色体上获得高分辨复制带带型。早、晚复制带纹可多达526条。确定了可作为每一条染色体标记的特征性晚复制区,绘制了牛蛙的染色体高分辩晚复制带带型模式图。以前人对蛙属某些其它种晚复制区及晚复制带型为参考,对蛙属一些种间染色体同源性进行了初步分析。     

用放线菌素D法在植物染色体上显示高分辨带

本文探索了植物染色体高分辨显带中的放线菌素 D(actinomycin D 简称 AM D)法,并报道了该方法在一粒小麦、圆锥小麦、大麦、玉米、黑麦等植物染色体上进行高分辨显带的结果。AMD 法的流程主要包括:放线菌素 D 和秋水仙素共同预处理植物种子根尖,Ohnuki′s液低渗,纤维素酶和果胶酶酶解,3:1的甲醇冰乙酸固定液固定,涂片法制片和 Wright-Giemsa 染色。该方法在多数实验植物的染色体上均显示出丰富的高分辨带纹。在早中期,多数染色体可显示出10条左右的清晰带纹。文章还分析了植物染色体较难显示高分辨带或 G带的原因,并讨论了放线菌素 D 在显带中的应用。     

斑马鱼粗线期二价体高分辨多重带模式图构建

采用碱性低渗结合高氯仿固定法, 由斑马鱼(Danio rerio)初级精母细胞获得了分散良好的减数分裂粗线期二价染色体分裂相, 且二价体上具有高分辨多重带, 其带纹特征和数目相对稳定, 重复性好. 参照人类细胞遗传学的国际命名法体制, 构建了斑马鱼粗线期二价染色体599条带纹的高分辨带模式图, 并对每条二价体进行了区带划分, 描述了其识别要点.     

中国人体细胞染色体高分辨G带模式图

本工作应用高分辨染色体技术,分析了31名健康汉族人外周血的高分辨G带,制作了中国人体细胞染色体的高分辨G带核型图。并经镜下比较和照片剪贴配对分析,认为中国人体细胞高分辨G带的带纹顺序与宽窄基本与人类细胞遗传学高分辨显带命名的国际体制(ISCN,1981)中高分辨G带模式图一致,但在850条带阶段,1、2、8和Y染色体的某些区带与ISCN(1981)的模式图有些差别,故重新描绘了这四个染色体的模式图。     

植物染色体G带及螺旋的研究

本文报道了采用胰酶,尿素,SDS和NaOH原位诱导黑麦,小麦和蚕豆染色体G带和螺旋的结果,所得的G带带纹众多,分布于整个染色体上,带纹数目与染色体收缩程度相关,个别细胞的同源染色体带纹可以配对,一些晚前期染色体的带纹已达高分辨水平,G显带处理时间过长,染色体螺旋结构往往被诱导出来,螺纹数与染色体收缩程序有关,螺旋方向具有多样性,本文还首次报道了植物染色体G带到螺旋的转化现象,在光镜下显G带的染色体在扫描电镜下呈现出螺旋的特征,作者还对植物染色体G带与螺旋的关系作了初步的讨论。     

植物染色体G带及螺旋的研究

本文报道了采用胰酶,尿素,SDS和NaOH原位诱导黑麦,小麦和蚕豆染色体G带和螺旋的结果,所得的G带带纹众多,分布于整个染色体上,带纹数目与染色体收缩程度相关,个别细胞的同源染色体带纹可以配对,一些晚前期染色体的带纹已达高分辨水平,G显带处理时间过长,染色体螺旋结构往往被诱导出来,螺纹数与染色体收缩程序有关,螺旋方向具有多样性,本文还首次报道了植物染色体G带到螺旋的转化现象,在光镜下显G带的染色体在扫描电镜下呈现出螺旋的特征,作者还对植物染色体G带与螺旋的关系作了初步的讨论。     

斑马鱼二价体制备与多重带显带的方法学探讨

采用碱性低渗结合高氯仿一步显带技术获得了斑马鱼二价体高分辨多重G带,所出现的带纹丰富,反差明显。采用地高辛为标记的以限制性内切酶AfuⅠ介导的原位切口平移技术使斑马鱼二价体上呈现出类G带的多重带,获得了明暗反差强烈的带纹结果。通过比较多个不同分裂相的多条染色体,发现带纹的分布具明显特征性．并且特征一致,带纹数目基本吻合。首次从方法学上对斑马鱼二价体的制备过程及多重带显带技术进行了分析、探讨和总结,力求将该技术程序化、系统化,使其具有可重复性和可操作性,并对显带的可能机理进行了讨论。     

大鳞副泥鳅粗线期二价染色体分带研究

报道了一种鱼类二价体显带的新,采用ＰＨ值在７．２－７．４之间的低涌液对大鳞副泥鳅精巢进行整体长低渗、卡诺固定液处理方法得到粗线期二阶染色体的高分辨Ｇ带,其带纹特征和数目相对稳定且清晰可辨。与胰酶显和ＥＤＴＡ显相比具有操作简单,耗时短以及二价体分散相对较好等特点,这一方法在所有显带方法中最为简便。     

家畜及实验动物高分辨染色体研究进展

高分辨染色体(High Resolution chromosome HRC)是指通过某种处理,获得有丝分裂早期染色体分裂相,早期染色体较中中期染色体长,显带后可以得到更多更细的带纹,从而提高人们对染色体的分辨力.Yuns, J. J(1976)首先以氨甲喋呤使细胞同步化法,建立了人类高分辨染色体技术.随之国内外许多学者对人类高分辨染色体进行了广泛而深入的研究.近几年,关于家畜和实验动物的高分辨染色体研究陆续亦有一些报道,但理论和应用方面的进展依然有限.本文试图就家畜和实验动物高分辨染色体研究的方法、进展以及意义进行阐述,同时提出值得探讨的几个问题.     

植物染色体G-带的初步研究

本文首次报道了川百台(Lilium davidii)、华山松(Pinus armardii)和七叶一枝花(Paris polyphylla)等植物染色体G-带研究结果。本试验的G-带与以往的C-带不同,C-带每条染色体上一般只有1-4条带,多分布在着丝点附近,而G-带则多达几十条,分布在整条染色体上,带纹清晰,前期染色体带呈颗粒状,中期染色体呈明显的带状,与哺乳动物染色体G-带很相似。G-带的数目取决于染色体浓缩的程度。前期染色体带纹数目是中期的三倍,接近人类高分辨带水平。对G-带带纹采用了自动光谱分析,波峰数值与带纹相符。作者同时介绍了胰酶法在植物染色体G-带中的应用。认为此方法既适合动物亦适用于植物。但植物G-带显示的关键可能不在胰酶法本身,而在合适的分裂时期及染色体处理技术。     

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。     

小麦染色体高分辨率G带的神经网络自动分析的研究

应用自组织特征映射神经网络原理与方法,建立了双层Ｋｏｈｏｎｅｎ神经网络,其第一层是从二维图象平面到二维特征平面的映射,用于染色体高分辨率带纹的提取和带纹参数的计算,第二层是高维特征参数阵列到二维聚类平面的映射,用于同源染色体的自动配对和分类。应用结果表明,该方法能快速、准确地实现对栽培小麦染色体高分辨率Ｇ带带纹图象的特征参数自动提取和自动配对。     

High-resolution analysis of DNA replication domain organization across an R/G-band boundary.

Establishing how mammalian chromosome replication is regulated and how groups of replication origins are organized into replication bands will significantly increase our understanding of chromosome organization. Replication time bands in mammalian chromosomes show overall congruency with structural R- and G-banding patterns as revealed by different chromosome banding techniques. Thus, chromosome bands reflect variations in the longitudinal structure and function of the chromosome, but little is known about the structural basis of the metaphase chromosome banding pattern. At the microscopic level, both structural R and G bands and replication bands occupy discrete domains along chromosomes, suggesting separation by distinct boundaries. The purpose of this study was to determine replication timing differences encompassing a boundary between differentially replicating chromosomal bands. Using competitive PCR on replicated DNA from flow-sorted cell cycle fractions, we have analyzed the replication timing of markers spanning roughly 5 Mb of human chromosome 13q14.3/q21.1. This is only the second report of high-resolution analysis of replication timing differences across an R/G-band boundary. In contrast to previous work, however, we find that band boundaries are defined by a gradient in replication timing rather than by a sharp boundary separating R and G bands into functionally distinct chromatin compartments. These findings indicate that topographical band boundaries are not defined by specific sequences or structures.     

达乌尔黄鼠显带染色体的研究

达乌尔黄鼠分布在我国北方及蒙古和苏联等区域,对牧草及农田危害甚大。有关达乌尔黄鼠的核型国内外已有报道(Lyapunova等,1970;蔡有余等,1985;马继霞等,1985)。签于其染色体的一些特征,达乌尔黄鼠有可能成为染色体工程及检测环境诱变剂等方面的实验材料。虽然苏联Lyapunova等(1978,1980)对黄鼠属某些种的G-带和C-带进行过比较研究,我国蔡有余等(1985)对达乌尔黄鼠的C-带和Ag-NOR进行了观察,但无法对其染色体进行逐个地准确识别,特别是对Χ染体色的正确识别。为此,我们对达乌尔黄鼠的显带染色体进行了较详细的研究。     

A high-resolution cytogenetic map of human chromosome 12: Localization of 195 new cosmid markers by direct R-banding fluorescence in situ hybridization

We have constructed a high-resolution cytogenetic map of human chromosome 12 with 195 newly isolated cosmids by direct R-banding flourescence in situ hybridization. The fluorescent signals of 195 clones were evenly distributed throughout chromosome 12, but sublocalized preferentially to R-positive bands. This high-resolution cytogenetic map with an average map distance of 0.73 Mb on bands can, in conjunction with a genetic linkage map, facilitate the analysis of chromosomal and molecular aberrations in genetic diseases and cancers. Moreover, the cytogenetic mapping data provide starting points for establishing contig maps with cosmid clones and yeast artificial chromosomes.     

Delineation of human prometaphase paracentromeric regions using sequential GTG- and C-banding

The centromeric-paracentromeric regions of high-resolution human chromosomes have not been examined in detail. It is not clear which bands in the paracentromeric regions are included within the heterochromatin and are therefore not clinically meaningful, and which bands are excluded. This makes breakpoint analysis in these regions difficult. Using sequential G- and C-banding of high-resolution chromosome preparations from four clinically normal subjects and from one patient with a very small interstitial deletion of the chromosome 16 long arm, we have made a detailed analysis of the centromeric-paracentromeric regions of each chromosome and of the entire Y chromosome at the 400, 550, and 800-850 band stages. We present here the results of analysis of preparations at the 800-850 band stage.     

金线蛙染色体G显带的方法学探索

采用自然老化、氯仿处理及EDTA显带法,首次在金线蛙（R.plancyt）有丝分裂中期染色体上成功显示出G带,带纹反差强烈、特征鲜明。比较了多个来自同一分裂相的同源染色体和不同分裂相的4条大染色体,发现其特征带纹高度一致,带纹数目基本吻合。该方法经济简便,结果稳定可靠。探讨了G显带的可能机制,对进一步开展金线蛙等两栖类的细胞遗传学研究具有一定的参考价值。 Explore on the Advanced Method of G-banding of Rana Plancyt QIAN Shui-ming,YU Qi-xing College of Life Sciences,Wuhan University,Wuhan 430072,China Abstract:Using the technique of natural aging,chloroform and EDTA treatment,well-resolved G-banding patterns were successfully obtained in Rana plancyt's mitosis chromosome firstly.The G-banding patterns appeared distinctive.When analyzing some homologous chromosomes from the same metaphase figures and four macrochromosomes from different metaphase figures,the characteristic and the number of the bands were well matched.The method in this study is also economic and simple and the result is stable and reliable.The possible mechanism of G-banding was primarily discussed.The application of this method in the cytogenetics research of Rana plancyt and other amphibians is expected. Key words：Rana plancyt; mitosis; G-banding     

Evidence for chromosome number reduction and chromosomal homosequentiality in the 24-chromosome Korean frog Rana dybowskii and related species

The karyotype of the Korean frog Rana dybowskii with its pattern of C-band heterochromatin distribution was numerically analyzed. There are 2n = 24 chromosomes in the karyotype representing a reduction in number from the typical 2n = 26 chromosome karyotype of Rana. The karyotype shows other evidence of reorganization relative to 26-chromosome species. The chromosomes grade smoothly in size from largest to smallest without the two size classes that are characteristic for 26-chromosome species. In contrast to many 26-chromosome species, there are few centromeric C-bands but many interstitial ones. C-bands for each homologous chromosome pair are distinctive. A prominent secondary constriction is located on one of the smallest chromosomes, chromosome 11, in a position similar to that seen in most 26-chromosome species. The karyotype of R. dybowskii is compared to those of other species of Rana known to have 2n = 24 chromosomes; it is most similar to that of R. chensinensis, less so that of R. ornativentris and less still to that of R. arvalis in terms of the positions of centromeres and secondary constrictions. C-bands as well as secondary constrictions in the karyotypes of these frogs show evidence of chromosomal homosequentiality. The process and possible consequences of chromosome number reduction from an ancestral 26-chromosome karyotype is also evident in the karyotypes of these closely allied palearctic frogs. Pericentric inversions followed by fusion of two small elements apparently produced a new chromosome, chromosome 6, occurring originally among northeast Asian populations.     

黑斑蛙的减数分裂研究

本文研究了黑斑蛙的减数分裂,发现其性染色体所形成的性二价体主要呈末端与末端联接,浓缩期占79.6％,中期Ⅰ占75％,这进一步证明黑斑蛙确实存在XY型性别决定机制,这种XY型性染色体虽形态相同,但已发生了质的分化,可能是同型异质。黑斑蛙的性染色体并不形成性泡,少数二价体有中间交叉。     

黑斑蛙核型、C-带及Ag-NORs 研究

本文采用外周血淋巴细胞培养法制备染色体标本,观察黑斑蛙的染色体标本,研究黑斑蛙的核型,C-带和Ag-NORs。研究结果表明：（1）黑斑蛙淋巴细胞染色体数目为2n=26,其中有5对大染色体和8对小染色体,核型是二型性核型;（2）分别对雌雄个体的中期分裂相进行观察,在第11号染色体长臂中部有明显的次缢痕,但变异核型次缢痕在第8号染色体长臂的中部;（3）在第5号染色体长臂上有一条明显的近端粒C-带;（4）第11号染色体是一对具有银染核仁形成区的同源染色体,且雌雄个体的银染位置相同。