中国林蛙地模标本染色体组型、C带和银带研究

本文报道中国林蛙地模标本的染色体组型、C带和银带。选用染色单体未分开的早中期分裂相制作C带可显示出较多带纹。研究结果表明,中国林蛙与亲缘关系较近的欧洲林蛙在染色体组型、C带和银带上均存在显著差异。再染色体进化上,欧洲林蛙比较原始,中国林蛙比较进化。     

中国林蛙地模标本染色体组型、C带和银带研究

本文报道中国林蛙地模标本的染色体组型、C带和银带。选用染色单体未分开的早中期分裂相制作C带可显示出较多带纹。研究结果表明,中国林蛙与亲缘关系较近的欧洲林蛙在染色体组型、C带和银带上均存在显著差异。再染色体进化上,欧洲林蛙比较原始,中国林蛙比较进化。     

中华大蟾蜍染色体分带和姐妹染色单体互换的研究

本文报道了中华大蟾蜍(Bufo bufo gargartzans)的C带和BrdUrd-Hoechst-Giemsa复制带,并以中华大蟾蜍为代表确立了两栖类体细胞的姐妹染色单体差别染色(SCD)方法。BrdUrd-Hoechst-Giemsa技术在两栖类的中期染色体上能显示可重复的复合带型。用这种方法我们鉴定中华大蟾蜍第10对同型染色体为ZZ/ZW型性染色体,所有雄性动物两个Z染色体的复制型是完全相同的(同步复制的),而雌性动物的Z和W染色体显示出异型复制型(不同步复制的)。在W染色体长臂近着丝粒处有一个较早的复制带,Z染色体则缺乏这个复制带。这些性染色体用C带和其他方法不能区分。此外,我们还测定了中华大蟾蜍淋巴细胞的SCE频率,发现其SCE频率比哺乳动物高,为7.83±0.49(m±S.E.)。     

黑眉锦蛇的有丝分裂染色体和减数分裂联会复合体的观察

本工作以C带、硝酸银染色、对黑眉锦蛇(Elaphe taeniura)的有丝分裂染色体进行了显微观察。其二倍体染色体数目2n=36,核型组成为16(8m+6sm+2t)大染色体+20微小染色体。C带显现于几乎所有染色体的着丝粒区,有一对插入型C带位于第6对端着丝粒染色体。一个银染核仁组织区(NORs)位于No.12小染色体。同时以界面铺张——硝酸银染色技术,对黑届锦蛇减数分裂精母细胞联会复合体(SC)的结构进行了亚显微观察。发现黑眉锦蛇的SC结构与其他动物的SC相似,是由两股平行的侧线组成,SC组型与有丝分裂染色体组型有较好的一致性。     

蚕豆染色体Giemsa带型及其在鉴别染色体畸变中的应用

本文用BSG染色体C带显示法,研究了两个蚕豆(Vicia faba)品种嘉定白和平鲁的染色体带型。 平鲁的染色体带型:(1)70％M染色体显示出三条带,一条付缢痕带,二条着丝点带(C臂、O臂各一条);30％M染色体却显现出四条带,除付缢痕带以外,有三条着丝点带(C臂两条,O臂一条)。(2)第二对染色体均有三条带,着丝点两侧有两条着色较浅的带,长臂中央有一条中间带。(3)第三对染色体只有两条带,均位于长臂,一条着丝点带,另一条中间带。(4)第四对染色体与第三对有相似的两条带,但是中间带特别阔,着色最深。(5)第五对染色体虽然也是在长臂上显示两条带,但中间带的位置稍偏着丝点方向。(6)     

茅舍血厉螨核型及染色体的C带、G带的研究

本文首次报道了一种革螨——茅舍血厉螨核型及染色体C带、G带的研究。用剖腹取卵法、玻璃纸压片、Giemsa染色,经分析茅舍血厉螨的核型,单倍体n=7,二倍体2n=14。 用氢氧化钡—吉姆萨技术显示茅舍血厉螨染色体C带。在第1、2、4、5染色体上出现恒定的C带部分,第3、6、7染色体上出现不恒定的C带部分。根据C带带型,茅舍血厉螨着丝点的位置可分为近中区域(sm),近端区域(St),末端区域(t)和末端点(T)四类。 G带分析用胰蛋白酶—吉姆萨技术显示。 本文对茅舍血厉螨的核型、革螨染色体研究中螨卵的收集方法和染液的改进、C带带型与着丝粒位置的确定和G带显带问题进行了讨论。     

小山蛙和中国雨蛙的核型及其C—带和银染的研究

采用骨骼细胞直接制备染色体标本法和BSG及Ag-NORs显带技术,研究了小山蛙(Rana minimus)和中国雨蛙(Hyla chinensis)的常规核型、C-带和Ag-NORs。小山蛙2n=26,有5对大型和8对小型染色体。第6对染色体短臂近着丝点处具次缢痕,并为C-带染色阳性,银带显示此次缢痕处,即是标准NORs。C-带显现于几乎所有染色体的着丝点区,插入型C-带少且弱,无端位带。中国雨蛙2n=24,有6对大型和6对小型染色体。次缢痕在第10对染色体长臂上,亦为C-带染色阳性,并与银染显示的标准NORs相一致。C-带分析表明,亦以着丝点C-带为主,插入型C-带少,无端位带。本文初步讨论了蛙科和雨蛙科的核学特征以及它们间的演化关系。     

赤链蛇染色体组型、C型和Ag—NORs的研究

以骨髓细胞为材料研究赤链蛇的染色体,结果表明该物种2n=46,由8对大型的和15对微小的染色体组成,AF＝50。性染色体的大小介于3号和4号之间,为ZW;8大型染色体均显示着丝粒C带,1－6号还显示浅染端粒C带。W染色体为整条C带阳性,该物种一对NOR位于7号染色体近着丝粒区。不同地理分布群赤链蛇核型可能经历过Z与W染色体不等交换。     

植物染色体N带的研究

本文研究了大麦、小麦、黑麦、蚕豆、洋葱等染色体的 N 带带型鉴定技术。采用了两种 N 带技术:第一,将染色体标本在5%三氯醋酸(90℃,6分钟)-0.1NHCI(60℃,6分钟)处理,Giemsa染色;第二,染色体标本经 IM NaH_2PO_4(92—94℃,3.5—8.5分钟)处理,Giemsa 染色。试验证明 N 带技术简单、快速,带型清晰。带型分析表明,N 带并非专一地显示核仁组织者。将上述植物的 N 带与 C 带比较,在有些植物中虽然有些 N 带区与 C 带区一致,但也有些区域仅显示出 N 带而无 C 带或仅显示 C 带而无 N 带。为此,N 带技术与 C 带技术的结合使用,将对染色体鉴别十分有价值。N 带同 C 带一样也是细胞遗传学中一个有用的标记。     

准噶尔雅罗鱼染色体核型及带型的初步研究

以肾细胞作材料,采用秋水仙素-低渗-空气干燥法、Ag-NORs、C-带和G-带显带技术对准噶尔雅罗鱼(Leuciscus merzbacheri)染色体进行了研究。结果表明:(1)准噶尔雅罗鱼2n=50,核型组成为18m+14sm+6st+12t,NF=82,没有异型性染色体分化。(2)Ag-NORs的数目在不同的细胞中表现出多态性,数目为1～2个,出现1个Ag-NORs的频率最低(10%),出现2个的频率最高(70%);Ag-NORs主要出现在m1对和m4对同源染色体上;未发现有Ag-NORs联合的现象。(3)准噶尔雅罗鱼的染色体均呈现C-带阳性,可分为着丝粒C-带和端粒C-带。(4)同源染色体上G-带带纹基本一致,其带纹在每对染色体上的数目及分布具有明显特征性。     

Variability of C-banding patterns in Japanese quail chromosomes.

Observations were made of the C-banding patterns in several cells from 182 Japanese quail embryos to detect presence of stable variants. Each of the eight largest autosomes contains a C-band at the centromeric region. The short arm of autosome 8 is C-band positive, as is the entire W chromosome. The Z chromosome consistently contains an interstitial C-band in the long arm and a less prominent one in the short arm. Distinct variants of chromosome 4 and the Z chromosome were observed. In the Z chromosome a C-band at the terminal region of the short arm was markedly elongated in some embryos. Likewise, the short arm of chromosome 4 was much more prominent in one or both of the homologues in some embryos. Most of the microchromosomes contain a prominent C-band. The heteromorphisms are useful chromosome markers to detect the origins of heteroploidy in early embryos.     

A cytogenetic survey of an institution for the mentally retarded

Summary Heteromorphisms of chromosomes 1,9, and 16 were studied by C-banding in a population of 403 mentally retarded individuals from diverse ethinic groups. A significant difference in the distribution of heteromorphisms was found among the different racial groups. The Orientals had a larger C-band on chromosome 1 and a smaller C-band on chromosome 9 than the other racial groups while the Caucasians had a larger C-band on chromosome 9. The Oriental group also had a significantly greater proportion of inverted C-band. No differences were found in the distribution of C-band heteromorphisms among different etiologic categories of mental retardation.     

Evidence for a highly differentiated sex chromosome heteromorphism in the salamander Necturus maculosus (Rafinesque)

The mitotic chromosomes of the neotenic (sensu Gould, 1977, and Alberch et al., 1979) salamander Necturus maculosus (Rafinesque) have been examined using a C-band technique to demonstrate the distribution of heterochromatin. The C-banded mitotic chromosomes provide evidence of a highly differentiated XY male/XX female sex chromosome heteromorphism, in which the X and Y chromosomes differ greatly in size and morphology, and in the amount and distribution of C-band heterochromatin. The X chromosome represents one of the largest biarmed chromosomes in the karyotype and is indistinguishable from similar sized autosomes on the basis of C-band heterochromatin. The Y chromosome, on the other hand, is diminutive, morphologically distinct from all other chromosomes of the karyotype, and is composed almost entirely of C-band heterochromatin. The discovery of an X/Y chromosome heteromorphism in this species is consistent with the observation by King (1912) of a heteromorphic spermatogenic bivalent. Karyological and phylogenetic implications are discussed.     

Cytochemical heterogeneity of the C-band in human chromosome 1

Summary The heterogeneity of the C-band of human chromosome 1 has been evaluated using several selective staining methods: C-banding (CBG), distamycin A plus 4-6-diamidino-2-phenylindole (DA/DAPI) and Giemsa G-11 pattern following the treatment with the restriction endonucleases AluI and HaeIII. The bands produced by each method are characteristic but not identical. The total C-band is resistant to AluI treatment. The bands induced by HaeIII and the one stained by DA/DAPI are markedly similar but smaller than the C-band. The G-11 technique stains yet smaller regions than those of HaeIII and DA/DAPI. Depending on the expression of staining properties, the C-band of chromosome 1 usually consists of three subdivisions: the proximal, intermediate and distal regions, suggesting an extremely heterogeneous nature. The staining variations between different regions are further substantiated by studies of a reciprocal translocation where the proximal region and the remaining C-band of chromosome 1 are separate.     

Patterns of exchange induced by mitomycin C in C-bands of human chromosomes. I. Relationship to C-band size in chromosomes 1, 9, and 16

Summary Frequencies of exchange were determined in C-bands of chromosomes 1, 9 and 16 in six normal males, and related to relative C-band area. Comparing these different chromosomes, more exchanges occurred on average in 9 than in 1 although their mean C-band sizes were similar. Chromosome 16 exchanges were fewer, both overall and relative to C-band area. Comparing the same chromosome between individuals, there was a positive correlation between relative frequency and band size in both 1-1 and 9-9 exchanges. No clear trend was observed for other exchange events.If homology is required for interchange, if cannot be dependent solely on overall C-band size. Perhaps certain DNA sequences, sensitive to mitomycin C damage, are located in part of each C-band, with less per unit area in chromosome 1 than in 9 and still less in chromosome 16.X- and U-type exchanges between chromosome 9s occurred in near equal frequencies in all individuals. If synapsis of specific, affected sequences is a pre-requisite for interchange, this observation suggests that the affected sequence in chromosome 9 is arranged in both orientations relative to the centromere.     

Sister chromatid exchange points in the heterochromatin and euchromatin regions of Chinese hedgehog chromosomes

Summary The Chinese hedgehog has a diploid chromosome number of 48 in which there are eleven pairs of telo- or subtelocentric autosomes, twelve pairs of meta- or submetacentric autosomes, a metacentric X chromosome and a telocentric Y chromosome. The heterochromatin is almost completely distributed in five large distal segments of chromosomes nos. 9 to 12 and no. 18. There is no positive C-band in the centromeres of the chromosomes except for the X chromosome which has a small, weakly stained C-band in the centromere. In Chinese hedgehog cells 52.1% of SCEs are found at the junction between the euchromatin and the heterochromatin, 39.5% in the heterochromatin and 8.4% in the auchromatin. The SCE number per unit C-band is double the SCE number per unit euchromatin. The SCE rate in the heterochromatin or euchromatin regions is not proportional to their chromosome length and can be quite different between different pairs of the chromosomes. Our results indicate that there is a non-uniform distribution of the SCEs in the Chinese hedgehog cells.     

Estimation of the sizes of polymorphic C-bands in man by measurement of DNA content of whole chromosomes.

A method is proposed for estimating the sizes of polymorphic C-bands of human chromosomes by microdensitometric measurement of the DNA content of whole chromosomes. The method requires measurements of: a chromosome known not to by polymorphic, as a standard against which to normalize all measurements; the polymorphic chromosomes of interest; and a homologous polymorphic chromosome lacking the C-band. In an example studies here, the C-band of chromosome 9 was estimated to contain about 0.0296 pg of DNA.     

大鳞副泥鳅ZZ/ZW型性别决定的细胞遗传学证据

大鳞副泥鳅是鲤形目、鳅科的鱼类。其2n数为48,核型组成为12m+4sm+32 t(雄性),11m+5sm+32t(雌性)。根据银染带和C带特征分析,证实大鳞副泥鳅为ZZ/ZW型性别决定。Z染色体为中部着丝粒染色体,在其长臂端部有Ag -NOR存在。 W染色体为亚中部着丝粒染色体,在其长臂末端也有Ag-NOR存在,同时还有一深染的居间C带,这是W染色体独有的带纹特征。 Abstract:Paramisgurnus dabryanus belongs to Cypriniformes,Cobitidae.Its 2n is 48.The karyotype formula is 12m+4sm+32t(in male),11m+5sm+32t(in female).According to the Ag-NORs band and C-band patterns,we consider that its sex determination is of ZZ/ZW type.The Z chromosome is a metacentric one with Ag-NORs located on its arm end.The W chromosome is a submetacentric with Ag-NORs located on the terminal of its long arm.There is a darkly stained C-band on the long arm of W chromosome.This band is a characteric of the W chromosome.     

福建大头蛙的核型及带型分析

利用骨髓细胞蒸气固定法制备染色体标本,研究了福建大头蛙(Limnonectesfujianensis)黄山居群的核型、C 带和Ag NORs。结果表明,福建大头蛙核型为2n =2 2 =2 0M 2SM ,NF =44,次缢痕位于No 1 0q ;各染色体均有着丝粒C 带,3p、9q出现插入型C 带;Ag NORs位于1 0q。     

A cloned repeated DNA sequence in human chromosome heteromorphisms

A sequence derived by ECoRI restriction of human satellite DNA III has been cloned in lambda gt WES. The cloned DNA was used as a template for in vitro synthesis of cRNA, which was hybridized in situ to preparations of human metaphase chromosomes with a range of heterochromatic polymorphisms. Most of the hybridization was found on chromosome 1, and the amount of hybridization was related to the size of the C-band on this chromosome. Hybridization to other chromosomes was not related to the C-band size, although hybridization of total satellite DNA is proportional to C-band size. Total satellite DNAs contain a mixture of sequences, some of which are predominantly located on only one pair of chromosomes. Hybridization in situ is able to discriminate between such chromosome-specific sequences and the bulk of satellite DNA. Further analysis of satellite DNAs may identify sequences specific for every chromosome pair.