植物减数分裂染色体配对与染色体组分析的研究进展

简要介绍了植物减数分裂染色体配对研究。综述了减数分裂染色体配对研究在鉴定异源易位系、确定多倍体物种类型、分析物种间亲缘关系和物种的染色体组来源及探讨杂种不育的细胞遗传学机制等诸多方面的应用进展。分析了影响染色体配对的主要因素, 如配对控制体系、遗传背景和外界环境条件等,并展望了染色体配对研究与其他技术结合在染色体组分析中的应用前景。     

雄性东亚钳蝎减数分裂和染色体组型

本文作者对我国药用动物东亚钳蝎——Buthusmartensi的精母细胞减数分裂和染色体组型进行初步观察。该虫的减数分裂有细线期、偶线期、粗线期、双线期和终变期。染色体数目24者居多,2n=24,即2n=22A+xy。染色体组型有3对为中部着丝粒染色体,7对亚中部着丝粒和1对端部着丝粒染色体。1对性染色体xy均为亚中部着丝粒染色体。     

卵巢发育阻滞的人工三倍体鱼减数分裂染色体配对的光镜观察

采用界面铺张制片和硝酸银一步染色的方法,对人工三倍体水晶彩鲫卵巢发育阻滞型个体的减数分裂染色体配对进行了光镜观察。在分化有初级卵母细胞的卵巢发育阻滞型的三倍体鱼中,减数分裂粗线期细胞主要的由二价体和单价体组成,也见有少量三价体和其它多价体,其染色体成员数大多在９０左右;在不同细胞间,染色体的大小变化较大;配对联会过程中形成的配对叉和产生的特异蛋白在一些细胞中明显可见。文中讨论了三倍体染色体配对紊乱     

中国雄鸡减数分裂SC组型和有丝分裂染色体组型的比较研究

以微铺展一硝酸银染色技术制备中国准鸡sc标本。电镜的定量SC组型分析表明：中国难鸡的so 组型和有丝分裂染色体组型有良好的一致性。并对个别SC与其相应的有丝分裂染色休在长度、形态士 的差异以及sc组型分析在鸟类细胞遗传学研究中的可能意义进行了讨论。     

长鬣蜥的染色体组型和减数分裂联会复合体的研究

本文报道长鬣蜥(Physignathus cocincinus)有丝分裂染色体及C-,Ag-带以及减数分裂联会复合体核型。染色体数2n=36,NF=48,核型组成为12V+24m(V为双臂大染色体,其中No.2为亚中着丝粒染色体,m为微小染色体)。结构异染色质主要分布在小染色体上。一对Ag-NORs分布于第2对亚中着丝粒染色体末端。     

美味猕猴桃原生质体再生植株细胞遗传学研究 Ⅲ.母株减数分裂前期Ⅰ染色体配对的光镜观察

首次报道在光镜下观察美味猕猴桃（品种：Ｎｏ．２６原生质体植株的母株）花粉母细胞（ＰＭＣ）染色体在减数分裂前期的配对,发现其配对和凝缩有明显不同步性。不同细胞间染色体配对形式变化较大,一般以二价联合为主,其次由其它多种配对方式（包括有复合配对,重复配对,着丝点或端粒处联合和多价联会）形成多价体,还有少数未配对或发生内配对（偶见）的单价体和几条二阶体之间的次级配对,粗线期观察到少数染色体有缺失（或重复     

美味猕猴桃原生质体再生植株细胞遗传学研究 Ⅲ .母株减数分裂前期Ⅰ染色体配对的光镜观察

首次报道在光镜下观察美味猕猴桃 (品种 :No.2 6原生质体植株的母株 )花粉母细胞( PMC)染色体在减数分裂前期的配对 ,发现其配对和凝缩有明显不同步性。不同细胞间染色体配对形式变化较大 ,一般以二价联会为主 ,其次由其它多种配对方式 (包括有复合配对、重复配对、着丝点或端粒处联合和多价联会 )形成多价体 ,还有少数未配对或发生内配对 (偶见 )的单价体和几条二价体之间的次级配对。粗线期观察到少数染色体有缺失 (或重复 )、倒位、易位和疏松配对等结构性改变。表明该植株是一个复杂的区段异源六位体 ,少数染色体在结构上累积有变异。还认为该植株是研究减数分裂染色体配对和联会机制的好材料。     

phlb基因诱导小麦ABD染色体组部分同源染色体配对的研究

通过花药培养首次获得了“中国春”phlb突变体单倍体,同时也获得了“中国春”单倍体。对其细胞学观察表明,前者花粉母细胞减数分裂中期Ⅰ每个细胞染色体交叉为5.08个,后者为1.30个。证明了phlb基因在单倍体状态下具有强的诱导ABD染色体组部分同源染色体间的配对作用。     

减数分裂中染色体不分离与染色体病

人类细胞减数分裂是精卵形成过程中的重要阶段。它包括染色体的一次复制 ,细胞的两次连续的分裂以及同源染色体配对、交换 ,同源染色体分离 ,姐妹染色单体分离等一系列复杂的过程。在细胞分裂进入中、后期时 ,如果其一对同源染色体或两姐妹染色单体未分别向两极移动 ,却同时进入一个子细胞中 ,结果细胞分裂所形成的两个子细胞中 ,一个将因染色体数目增多而形成超二倍体 ,一个则由于染色体数目减少而形成亚二倍体。这一过程称染色体不分离 (ｃｈｒｏｍｏｓｏｍａｌｎｏｎ -ｄｉｓｊｕｎｃｔｉｏｎ) ,从而引起配子中染色体数目异常 ,产生非整…     

中国雉鸡减数分裂SC组型和有丝分裂染色体组型的比较研究

以微铺展-硝酸银染色技术制备中国雉鸡SC标本。电镜的定量SC组型分析表明:中国雉鸡的SG组型和有丝分裂染色体组型有良好的一致性。并对个别SC与其相应的有丝分裂染色体在长度、形态上的差异以及SC组型分析在鸟类细胞遗传学研究中的可能意义进行了讨论。     

Molecular Mechanisms of Homologous Chromosome Pairing and Segregation in Plants

In most eukaryotic species, three basic steps of pairing, recombination and synapsis occur during prophase of meiosis I. Homologous chromosomal pairing and recombination are essential for accurate segregation of chromosomes. In contrast to the well-studied processes such as recombination and synapsis, many aspects of chromosome pairing are still obscure. Recent progress in several species indicates that the telomere bouquet formation can facilitate homologous chromosome pairing by bringing chromosome ends into close proximity, but the sole presence of telomere clustering is not sufficient for recognizing homologous pairs. On the other hand, accurate segregation of the genetic material from parent to offspring during meiosis is dependent on the segregation of homologs in the reductional meiotic division （MI） with sister kinetochores exhibiting mono-orientation from the same pole, and the segregation of sister chromatids during the equational meiotic division （MII） with kinetochores showing bi-orientation from the two poles. The underlying mechanism of orientation and segregation is still unclear. Here we focus on recent studies in plants and other species that provide insight into how chromosomes find their partners and mechanisms mediating chromosomal segregation.     

应用荧光原位杂交和染色体配对研究八倍体小冰麦中2的染色体组构成及染色体特征

通过染色体配对分析和荧光原位杂交（ＦＩＳＨ）技术对八倍体小冰麦中２的染色体组构成进行分析,结果表明：八倍体小冰麦中２含有的冰草染色体是来自天蓝冰草（Ａｇｒｏｐｙｒｏｎ　ｉｎｔｅｒｍｅｄｉｕｍ（Ｈｏｓｔ）Ｐ．Ｂ．＝Ｅｌｙｔｒｉｇｉａ　ｉｎｔｅｒｍｅｄｉａ（Ｈｏｓｔ）Ｎｅｖｓｋｉ＝Ｔｈｉｎｏｐｙｒｕｍ　ｉｎｔｅｒｍｅｄｉｕｍ　（Ｈｏｓｔ）Ｂａｒｋｗｏｒｔｈ　ａｎｄ　Ｄｅｗｅｙ）具同亲关系的染色体组,但冰草的这种同亲关系的染色体组不同于二倍体长穗偃麦草（Ｔｈｉｎｏｐｙｒｕｍ　ｅｌｏｕｇａｔｕｍ　２Ｘ）的Ｅ组染色体。中２含有１２条冰草染色体,且有一对染色体为小麦（Ｔｒｉｔｉｃｕｍ　ａｅｓｔｉｖｕｍ　Ｌ．）染色体和冰草染色体之间易位所形成的。     

Ten Years of Gene Discovery for Meiotic Event Control in Rice

Meiosis is the crucial process by which sexually propagating eukaryotes give rise to haploid gametes from diploid cells. Several key processes, like homologous chromosomes pairing, synapsis, recombination, and segregation, sequentially take place in meiosis. Although these widely conserved events are under both genetic and epigenetic control, the accurate details of molecular mechanisms are continuing to investigate. Rice is a good model organism for exploring the molecular mechanisms of meiosis in higher plants. So far, 28 rice meiotic genes have been characterized. In this review, we give an overview of the discovery of rice meiotic genes in the last ten years, with a particular focus on their functions in meiosis.     

Characterization of Genome and Chromosomes in Octoploid Wheat wheatgrass Amphiploid Zhong 2 Using Fluorescence in situ Hybridization and Chromosome Pairing Analysis

Genomic constitution of octoploid wheat-wheatgrass amphiploid Zhong 2 was analyzed by chromosome pairing and fluorescence in sim hybridization techniques. The results indicated that the octoploid wheatwheatgrass chromosomes in Zhong 2 were derived from the distant homologous genomes of wheatgrass ( Agropyron intermedium (Host) P.B. = Elytrigia intermedia (Host) Nevski = Thinotopyrum intermedium (Host) Barkworth and Dewey, and thew distant homologous genomes were not from the E geaome of T. elongatum 2x. Zhong 2 contained 12 wheatgrass chromosomes in which a pair of chromosomes was involved in translocation between wheatgrass and wheat chromosomes.     

窄颖仲彬草生物系统学研究

窄颖仲彬草Ｋｅｎｇｙｉｌｉａ ｓｔｅｎａｃｈｙｒａ（Ｋｅｎｇ） Ｊ．Ｌ． Ｙａｎｇ ,Ｙｅｎ ｅｔ Ｂａｕｍ 是分布于我国西部的一种多年生六倍体植物。将其与犬草Ｅｌｙｍｕｓ ｃａｎｉｎｕｓ（Ｌ．） Ｌ．, 鹅观草Ｒｏｅｇｎｅｒｉａ ｋａｍｏｊｉ Ｏｈｗｉ, 糙毛仲彬草Ｋ．ｈｉｒｓｕｔａ （Ｋｅｎｇ） Ｊ．Ｌ．Ｙａｎｇ,Ｙｅｎ ｅｔ Ｂａｕｍ ３ 个种进行了杂交。对亲本及杂种Ｆ１ 代花粉母细胞减数分裂中期Ｉ染色体配对行为进行了观察。减数分裂平均构型分别为： Ｅ． ｃａｎｉｎｕｓ×Ｋ． ｓｔｅｎａｃｈｙｒａ２３－７９ Ⅰ＋ ５－２０ Ⅱ＋ ０－２７Ⅲ; Ｒ．ｋａｍｏｊｉ ×Ｋ．ｓｔｅｎａｃｈｙｒａ１８－２３ Ⅰ＋ １１－６８ Ⅱ＋ ０－０６ Ⅲ＋ ０－０６ Ⅳ; Ｋ．ｈｉｒｓｕｔａ ×Ｋ．ｓｔｅｎａｃｈｙｒａ４－８３Ⅰ＋ １７－３１ Ⅱ＋ ０－５５ Ⅲ＋ ０－２０ Ⅳ＋ ０－０２ Ⅴ。根据以上结果, 结合种的形态特征, 窄颖仲彬草应从鹅观草属Ｒｏｅｇｎｅｒｉａ Ｃ． Ｋｏｃｈ 拟冰草组ＰａｒａｇｒｏｐｙｒｏｎＫｅｎｇ 中组合到仲彬草属Ｋｅｎｇｙｉｌｉａ Ｙｅｎ ｅｔ Ｙａｎｇ。     

Meiotic pairing in hybrids between tetraploid Triticale and related species: new elements concerning the chromosome constitution of tetraploid Triticale

Summary Two F5 strains of tetraploid triticale (2n= 4x=28), obtained from 6x triticaleX2 rye progenies, were crossed with diploid and tetraploid rye, some durum and bread wheats, and various 8x and 6x triticale lines. Meiosis in the different hybrid combinations was studied. The results showed that the haploid complement of these triticales consists of seven chromosomes from rye and seven chromosomes from wheat. High frequencies of PMCs showing trivalents were observed in hybrids involving the reference genotypes of wheat and triticale. These findings proved that several chromosomes from the wheat component have chromosome segments coming from two parental wheat chromosomes. The origin of these heterogeneous chromosomes probably lies in homoeologous pairing occurring at meiosis in the 6x triticaleX2x rye hybrids from which 4x triticale lines were isolated. A comparison among different hybrids combinations indicated that the involvement of D-genome chromosomes in homoeologous pairing is quite limited. In contrast, meiotic patterns in 4x triticale X 2x rye hybrids showed a quite high pairing frequency between some R chromosomes and their A and B homoeologues.     

东方山羊草、尾状山羊草中染色体配对控制机制的存在和作用

直接杂交与幼胚培养方法结合获得了小麦与东方山羊草、尾状山羊草属间杂种。Ｆ１杂种细胞遗传学研究发现,东方山羊草的染色体组显著促进部分同源染色体配对,完全掩盖了小麦ｐｈ１ｂ基因的作用,尾状山羊草的染色体组一定程度抑制部分同源染色体配对,尤其强烈抑制小麦ｐｈ１ｂ基因的作用。表明东方山羊草的Ｓ染色体组上存在类似于小麦的ｐｈ１ｂ基因,尾状山羊草的Ｃ染色体组上存在类似于小麦的Ｐｈ１基因     

黄瓜花粉母细胞减数分裂行为的研究

研究了华北型、华南型和西南型黄瓜花粉母细胞的减数分裂行为,发现黄瓜细胞核减数分裂的同步性较高,细胞质是同时型分裂。在细胞核分裂的过程中,核仁在前期Ⅰ到中期Ⅰ逐渐消失,在前期Ⅰ再次出现,随后消失;染色体在前期Ⅰ到中期Ⅰ逐渐收缩,变得清晰,至末期Ⅰ解螺旋,变得模糊,在前期I再次清晰。不同生态型黄瓜终变期的染色体构型均以环状二价体为主。在前期Ⅰ和前期Ⅰ,西双版纳黄瓜的核仁都相应地比另外两种生态型黄瓜品种的多,在后期Ⅰ还偶尔出现染色体桥,显示了西双版纳黄瓜变种的特殊性。研究还发现寒冷的气候条件下栽培黄瓜都能够形成高频率的多分体,推测其形成很可能与低温逆境有关。