鱼类染色体显带的研究进展

全世界现存鱼类约有２００００种左右,分属４６目,４５０科,４０３２属［１］。其中淡水鱼类占４１２％,是脊椎动物分布最广,种类最多的类群,具有多种多样的生物学特性和重大的经济价值［１］。在脊椎动物中,鱼类的染色体较小,数目偏多,研究工作难度较大。早期...     

应用G显带染色体荧光原位杂交（FISH）技术研究复杂的染色体易位

建立常规Ｇ显带染色体标本的荧光原位杂交（ＦＩＳＨ）技术,用于分析患者复杂的染色体易位。原位杂交前,用甲醛固定Ｇ显带标本,是获得良好显带和荧光杂交效果的关键步骤。仅用常规细胞遗传学方法分析,显示一例习惯性流产患者的核型为４６,ＸＸ,ｔ（１;５;１２）（１ｐｔｅｒ→１ｑ２５：：１２ｑ２４→１２ｑｔｅｒ;５ｑｔｅｒ→５ｐ１１：：１ｑ２５→１ｑｔｅｒ,１２ｐｔｅｒ→１２ｑ２４：．５ｐ１１→５ｐｔｅｒ）,而采用本方法确定患者的核型实际为４６,ＸＸ,ｔ（１;５,１２）（１ｐｔｅｒ→１ｑ２３：：１２ｑ２２→１２ｑｔｅｒ,５ｑｔｅｒ→５ｐ１１：：１ｑ２５→１ｑｔｅｒ;１２ｐｔｅｒ→１２ｑ２２：：１ｑ２３→１ｑ２５：５ｐ１１→５ｐｔｅｒ）。结果表明,新建立的Ｇ显带染色体荧光原位杂交（ＦＩＳＨ）技术能更有效地检测患者复杂的染色体易位。     

鱼类染色体BSG-G显带法

鱼类染色体多重带技术的应用,对鱼类遗传变异、分类进化、基因定位、基因表达与调控等问题的深入研究,显得日益重要。然而,鱼类染色体的多重带显带一直是个尚未过关的技术难题。近年来,许多学者尤其是国内学者在这个领域中进行了很多探索,并已取得一定进展。鉴于鱼类染色体短小,中期染色体螺旋     

染色体显带机制研究若干进展

染色体分带技术的迅速发展,尤其是当今植物染色体高分辨G-带技术的突破,不仅为染色体鉴别、基因定位等提供了重要手段,对细胞分类学、物种生物学、细胞地理学、体细胞遗传学,以及育种学、人类遗传学和环境保护等领域的应用与发展,发挥着越来越大的作用。众多学者对染色体显带机制进行了研究。最早,用DNA变性与复性理论作为染色体显带的基础,认为是DNA的彻底变性和高度重复DNA的差别退火,导致分带程序中选择性染色的出现。实际上,染色体显带机制并非如此简单,许多实验结果均与上述解释相矛盾。近来的研究表明,染色体显带的核心问题是,     

应用G显色带染色体荧光原位杂交（FISH）技术研究复杂的染色体易位

建立常规Ｇ显带染色体标的荧光原位杂交（ＦＩＳＨ）技术,用于分析患者复杂的染色体易位,原位杂交前,用甲醛固定Ｇ显带标本,是获得良好显带和荧光杂交效果的关键步聚,仅用常细胞遗学方法分析,显示一例习惯性流产患者的核型为４６,ＸＸ,ｔ（１;５;１２）（１ｐｔｅｒ→１ｑ２５：：１２ｑ２４→１２ｑｔｅｒ;５ｑｔｅｒ→５ｑ１１：：１ｑ２５→１ｑｔｅｒ;１２ｐｔｅｒ→１２ｑ２４;：５ｐ１１→５ｐｔｅｒ）而采用本方     

哺乳动物染色体高分辨显带研究现状

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休 （指晚前期、前中期、早中期染色体）分裂相,此时分裂 相的染色体较中中期染色体长,显带后可得到更多更 细的带纹,从而提高了人类对染色体的分辨力。Yunis (1976)134'首先以氨甲喋吟使细胞同步化,再使细胞 短时暴露于秋水酸胺中,从而提出了对400, 5-50,850 和1200条带时期的染色体进行研究的技术,高分辨染 色体应运而生。接着国内外许多学者对人类染色体进 行了高分辨分带研究『’一,,‘,一,‘’。人类细胞遗传学命名 常务委员会（1981)制定了人类高分辨染色体显带命名 的国际体制‘’‘’。这项工作大大促进了人类染色体高 分辨的研究,目前这项技术已经广泛应用于临床医 学‘4-1,t8,11,37 3。动物遗传学家借鉴人类高分辨染色 体技术对一些哺乳动物的染色体进行了高分辨研 究“,,,,之盆,川,但理沦和应用方面的研究均进展较'R o 本文对哺乳动物高分辨染色体研究的方法、进展以及 意义进行了阐述,同时提出了值得探讨的几个问题。     

大熊猫与黑熊显带染色体的比较研究

以体外培养的大熊猫（Ａｉｌｕｒｏｐｏｄａｍｅｌａｎｏｌｅｕｃａ）与黑熊（Ｓｅｌｅｎａｒｃｔｏｓｔｈｉｂｅｔａｎｕｓ）外周血淋巴细胞为实验材料,应用ＢｒｄＵ复制带显示技术,研究了大熊猫和黑熊染色体晚复制带带型。通过对大熊猫与黑熊显带染色体带型的比较,发现黑熊部分具端着丝粒的染色体与大熊猫部分具中,亚中,或亚端着丝粒的染色体的整个短臂或整个长臂有明显的带型相似性,在黑熊具中,亚中着丝粒染色体中,仅３３     

大熊猫(Ailuropoda melanolenca)显带染色体的研究

大熊猫系我国特产的世界珍稀动物,素有“活化石”和“国宝”之称。限于材料来源,虽有核型的少数报道（邓承宗等,1980;陈文元等,1984;Newnham et al.,1966）,但研究尚不够深入。1980年,Wurster-Hill和Bush首先报道了大熊猫（）的显带核型,并与杂交熊等比较,探讨了大熊猫的分类地位。本文对四只大熊猫的G带、C带核型和Ag-NORs作了分析,绘制了G带核型模式图,并提出了某些商榷的意见。     

三倍体草鱼染色体限制性内切酶带分析

本文报道运用Ｇｉｅｍｓａ染色、Ｃ－带显带、ＮＯＲ－显带和多种限制性内切酶消化对草鱼三倍体的染色体进行分析。其中,内切酶ＨａｅⅢ和ＨｉｎｄⅢ等使染色体产生Ｇ－带,其余内切酶产生与常规Ｃ－带不同的分化,即所谓修饰Ｃ－带。实验结果表明,限制性内切酶可使鱼类染色体产生多种带型,各种显带技术的结合使用,可探讨鱼类染色体及染色质结构与进化。     

植物染色体G—显带的AEG法

目前,植物染色体G—显带的方法很多,有胰酶法、尿素法,改良的Seabright法、Utakoji法、醋酸地衣红法、ASG法和风油精诱导等几种,都取得了显著的效果。在广泛实验研究的基础上,我们摸索出了     

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。     

两栖动物性染色体的多样性及其进化机制的研究进展

两栖动物性别决定类型和性染色体具有多样性的特点。在已发现异形性染色体两栖动物中,大部分物种Y或W染色体大于其对应的X或Z染色体,少数物种具有高度分化的Y或W染色体。同时两栖动物类群内基因组大小差异大,性染色体间分子水平上也存在差异。高频转换、偶然重组和染色体重排可能是两栖动物性染色体进化过程中的关键机制。本综述通过对两栖动物性染色体进化的深入探讨,揭示其遗传性别决定的机理,有助于对两栖动物性别人工调控的进一步探索。     

Karyotype and Sex Chromosomes in Cephalotaxus sinensis

In Cephalotascus sinensis (Rehd. et Wils. ) Li the somatic chromosome number was found to be of 2n=24. Eleven pairs of chromosomes possessed their centromeres at median or median-submedian regions. The shortest pair of chromosomes was the SAT chromosome which possessed their centromeres at the submedian regions. The sex chromosomes were demonstrated by the Giemsa C-banding technique. The sexual determination mechanism of female was WZ type (2n=24=22A+WZ), and that of male was ZZ type (2n=24=22A +ZZ).     

Banding Human Chromosomes Using a Combined C-Banding-Fluorochrome Staining Technique

Slides pretreated for C-banding and stained with DAPI or CMA3 show different banding patterns in human metaphase chromosomes compared to those obtained with either standard Giemsa C-banding or fluorochrome staining alone. Human chromosomes show C-plus DA-DAPI banding after C-banding plus DAPI and enhanced R-banding after C-banding plus Chromomycin A3 staining. If C-banding preferentially removes certain classes of DNA and proteins from different chromosome domains, C-banding pre-treatment may cause a differential DNA extraction from G- and R-bands in human chromosomes, resulting in a preferential extraction of DNA included in G-bands. This hypothesis is partially supported by the selective cleavage and removal of DNA from R-bands of restriction endonuclease HaeIII with C-banding combined with DAPI or Chromomycin A3 staining. Structural factors relating to regional differences in DNA and/or proteins could also explain these results.     

Sex Determination by Sex Chromosomes in Dioecious Plants

Abstract: Sex chromosomes have been reported in several dioecious plants. The most general system of sex determination with sex chromosomes is the XY system, in which males are the heterogametic sex and females are homogametic. Genetic systems in sex determination are divided into two classes including an X chromosome counting system and an active Y chromosome system. Dioecious plants have unisexual flowers, which have stamens or pistils. The development of unisexual flowers is caused by the suppression of opposite sex primordia. The expression of floral organ identity genes is different between male and female flower primordia. However, these floral organ identity genes show no evidence of sex chromosome linkage. The Y chromosome of Rumex acetosa contains Y chromosome-specific repetitive sequences, whereas the Y chromosome of Silene latifolia has not accumulated chromosome-specific repetitive sequences. The different degree of Y chromosome degeneration may reflect on evolutionary time since the origination of dioecy. The Y chromosome of S. latifolia functions in suppression of female development and initiation and completion of anther development. Analyses of mutants suggested that female suppressor and stamen promoter genes are localized on the Y chromosome. Recently, some sex chromosome-linked genes were isolated from flower buds of S. latifolia.     

Specific Heterochromatic Banding of Metaphase Chromosomes Using Nuclear Yellow

The bis-benzimidazole compound nuclear yellow (NY) belongs to the same chemical family as the DNA binding fluorochromes Hoechst 33258 and Hoechst 33342. Spectroscopic studies of NY alone and in the presence of calf thymus DNA show high DNA binding affinity and behavior similar to the Hoechst fluorochromes above. Mitotic metaphase chromosomes from Balb/c mice stained with NY show C-banding and weak G/Q-banding, both of them disappearing after distamycin A (DA) or methyl green (MG) counterstaining. The same staining of human metaphase chromosomes from lymphocyte cultures, however, reveal only faint G/Q-banding (NY) and a characteristic DA-DAPI-like banding (NY-DA, NY-MG). Image analysis of NY stained human chromosomes, confirms that NY is suitable for studying polymorphisms affecting size in the pericentromeric hete-rochromatin of pairs 1, 9 and 16, and shows significant enhancement of NY fluorescence induced by DA in DA-DAPI heterochromatin. Our spectroscopic and cytological results show that NY, either alone or counterstained with DA or MG, can be used for DNA cytochemistry and chromosome banding. Possible mechanisms for the banding patterns induced by NY are discussed.     

Specific Heterochromatic Banding of Metaphase Chromosomes Using Nuclear Yellow

The bis-benzimidazole compound nuclear yellow (NY) belongs to the same chemical family as the DNA binding fluorochromes Hoechst 33258 and Hoechst 33342. Spectroscopic studies of NY alone and in the presence of calf thymus DNA show high DNA binding affinity and behavior similar to the Hoechst fluorochromes above. Mitotic metaphase chromosomes from Balb/c mice stained with NY show C-banding and weak G/Q-banding, both of them disappearing after distamycin A (DA) or methyl green (MG) counterstaining. The same staining of human metaphase chromosomes from lymphocyte cultures, however, reveal only faint G/Q-banding (NY) and a characteristic DA-DAPI-like banding (NY-DA, NY-MG). Image analysis of NY stained human chromosomes, confirms that NY is suitable for studying polymorphisms affecting size in the pericentromeric hete-rochromatin of pairs 1, 9 and 16, and shows significant enhancement of NY fluorescence induced by DA in DA-DAPI heterochromatin. Our spectroscopic and cytological results show that NY, either alone or counterstained with DA or MG, can be used for DNA cytochemistry and chromosome banding. Possible mechanisms for the banding patterns induced by NY are discussed.     

鱼类基因组结构研究——Ⅰ.染色体的限制性内切酶显带

本文报道了1种新的鱼类染色体研究方法——限制性内切酶显带技术。我们应用限制性内切酶Bsp631等分别对黄鳝和长春鳊的染色体进行显带处理,结果表明,Bsp631能使这两种鱼的染色体发生稳定的带纹分化:适度的处理产生多重的G-带状带型,而过度的处理则产生特殊的限制性内切酶抗性带型。根据显带结果分析,我们对鱼类染色体限制性内切酶显带的可行性和实用价值进行了讨论。     

Trypsin-Orcein Banding in Plant Chromosomes

A convenient and quick method using trypsin-orcein for handing plant chromosomes (O-banding) is suggested. The technique is directly applicable to meristematic tissues (e.g. root tip) and involves the treatment of root tip with 1-2% solution of trypsin either in buffer or in 05 N HCI for 5-10 minutes at 37 C or for 30-60 minuta near 0 C followed by staining with 1.5% acetic orcein: 1 N HCI (19:1). Dark staining bands are reproducible and species specific. These bands possibly represent specific DNA-protein-dye interaction.