黄鳝体内寄生胃瘤线虫的染色体核型及G-带分析

采用常规空气干燥法制片,对寄生于黄鳝(Monopterus albus)体腔内的胃瘤线虫(Eustrongylidesignotus)染色体核型进行分析。结果表明:胃瘤线虫体细胞有12条染色体,为二倍体,核型公式为2n=12=10 m+2 sm。由5对常染色体和1对性染色体组成,性别决定模式为XX-XY,其中X、Y和1～4号染色体都为中着丝粒染色体,5号为亚中着丝粒染色体。每对染色体都有特定的G-带带型。     

Chromosomal banding pattern and idiogram of the cotton rat,Sigmodon arizonae (Rodentia,Muridae)

A procedure for obtaining G-bands on chromosomes of mammals is outlined. The procedure was utilized in an investigation of the idiogram and banding pattern of the mitotic chromosomes of the cotton rat, Sigmodon arizonae. The diploid number of this species is 22, and each pair of homologues is easily separated on the basis of size, centromeric position, and banding pattern. The autosomes are represented by four pairs of large submetacentric chromosomes, three pairs of medium to small submetacentric chromosomes, two pairs of large subtelocentric chromosomes and one pair of small acrocentric chromosomes. The X chromosome is acrocentric and averages from 5.42% to 5.46% of the haploid female complement. The Y chromosome is a minute acrocentric and easily separated from the smallest acrocentric autosome. The usefulnes of Sigmodon arizonae as a laboratory animal for cytogenetic studies is substantiated.     

Karyotypic characterization of Iheringichthys labrosus (Pisces, Pimelodidae): C-, G- and restriction endonuclease banding

Various chromosomal banding techniques were utilized on the catfish, Iheringichthys labrosus, taken from the Capivara Reservoir. C-banding regions were evidenced in telomeric regions of most of the chromosomes. The B microchromosome appeared totally heterochromatic. The restriction endonuclease AluI produced a banding pattern similar to C-banding in some chromosomes; the B microchromosome, when present, was not digested by this enzyme and remained stained. G-banding was conspicuous in almost all the chromosomes, with the centromeres showing negative G-banding. When the restriction endonuclease BamHI was used, most of the telomeres remained intact, while some centromeres were weakly digested. The B chromosome was also not digested by this enzyme. The first pair of chromosomes showed a pattern of longitudinal bands, both with G-banding and BamHI; this was more evident with G-banding. This banding pattern can be considered a chromosomal marker for this population of I. labrosus.     

玉米染色体G—带带型的研究

本文对3个玉米自交系,及其中两个自交系的杂交F_1有丝分裂早中期染色体的G-带带型进行了比较研究。所有的供试材料G-显带的染色体上都具有两种类型的带纹,我们称A型带和B型带。A型带为沿染色体长轴分布,较细的,密切邻近的多重带纹。不同自交系的A型带带型基本相同,杂交F_1的A型带无明显的异型性。非同源染色体间带型各不相同,某些染色体具有易于识别,特征性较强的A型带标记。B型带一般为深染色的大带,位于染色体的近端区。同一自交系每两个同源染色体的B型带可以配对,不同自交系B型带带型互有不同。杂交F_1某些染色体上的B型带带型异型性明显。具异型性的染色体对中一成员的带型与一个亲本相似,另一成员与另一亲本相似。比较对同一细胞先后作G-和C-显带处理的结果表明,B型带和C-带是相同的。     

Chromosome banding homologies in three species of Aedes (Stegomyia)

The chromosome complements of the mosquitoes Aedes aegypti, Aedes mascarensis, and Aedes albopictus, belonging to the subgenus Stegomyia, gave a uniform response to the Q-, H-, and R-banding techniques. Of the three homomorphic chromosome pairs, only the shortest or sex pair (I) showed a consistent banding pattern. In the three species, a bright yellow intercalary band was present on one arm of both chromosomes of the sex pair after heat treatment and staining with acridine orange. The rest of the chromosome and the other two pairs fluoresced orange-red. The same intercalary region appeared completely dark with the fluorochromes quinacrine and Hoechst 33258, while the rest of the chromosomes fluoresced dull. The same banding pattern was present in males and females. Size variations of the Q- and H-negative and R-positive intercalary bands were observed within each species. The results are interpreted in terms of structural homology of the sex-determining chromosomes, which is retained within the subgenus.     

大麦G—显带核型的研究

本文报道了 ASG 法处理的三个栽培大麦(Hordeum Vulgare)品种 G-带的核型研究。结果表明无论是早中期或中期染色体都显示出了密切邻近的、多重的 G-带带纹。在有丝分裂过程中染色体愈浓缩带纹数目愈少。同源染色体之间带纹分布的位置、染色深浅以及带纹数目都基本一致,可以较为准确地进行配对。同一分裂时期不同染色体的 G-带带纹各具一定的特点,可以作为鉴别的标记。讨论了显带技术和中期染色体的 G-带等问题。     

Studies on G-Banding Karyotype in Barley (Hordeum vulgare)

G-banding karyotypes of three cultivars in barley were analyzed. Multiple closely adjacent G-bands were able to be observed in each early metaphase or metaphase chromosome treatted by an ASG method. The more concentrated the chromosome, the less was the number of G-bands during mitosis. The position of band distribution, staining degree and band numbers between homologous chromosomes were basically identical. Chromosome pairing for karyotype analysis could be carried out more accurately. G-banding patterns of different chromosome pairs were not the same, they could be used as the markers to distinguish one from another chromosome pair. During the same mitotic stage the banding patterns including number, relative position and staining degree of the bands between different cultivars were basically the same, but they had differences in the size and staining degree of some bands near centromeres. G-banding technique and G-banding of metaphase chromosomes were discussed.     

Computer assisted karyotype analysis of Pyrrhopappus carolinianus

With the help of Computer Aided Karyotyping procedures, Ag-NOR staining and C-banding techniques, the karyotype of Pyrrhopappus carolinianus (Asteraceae, Lactuceae) has been studied. The species has 2n=12 chromosomes. Silver staining reveals that the two shortest pairs of chromosomes possess NOR's. On the basis of chromosome length and centromere position, only the longest chromosome pair and the satellite chromosomes can be identified. Two types of C-banding can be obtained, dependent on the temperature of the hydrochloric acid hydrolysis of the root tips. Hydrolysis at 60°C results exclusively in centromeric bands, whereas a treatment at room temperature reveals a pattern of intercalary bands. A computer assisted analysis of the intercalary banding pattern resulted in the construction of schematic representation of the average C-banding pattern. This banding pattern allows an easy identification of each of the chromosome pairs.     

Trypsin G- and C-banding for interchange analysis and sex identification in the chicken

The trypsin banding methods were applied to feather pulp and embryonic material of the chicken. Two contrasting types of chromosomal banding patterns were obtained by varying the duration of trypsin treatment. A short time treatment shows a G-banding pattern which has characteristic and distinctive bands along the chromosome arms. Prolonging the trypsin treatment causes the G-banding pattern to disappear, and only the centromeres and the W chromosome remained heterochromatic which is characteristic of the C-banding pattern. The application of the G-banding pattern analysis was used to identify regions of chromosomes involved in rearrangements. The simplified trypsin technique which produces the C-banding pattern makes it relatively easy to identify the W sex-chromosome and determine sex in avian species.     

马尾松染色体荧光带型的研究

对马尾松有丝分裂中期染色体荧光带纹的分析结果表明,其色霉素Ａ的染色体的荧光带赤;１对为着丝粒区和臂间我均有带纹的中间着丝染色体。６对为臂间区有带纺的中间着丝粒染色体;２对为着丝粒区有带纹的中间着丝粒染色体;３对无带纹的中间或近中着丝粒染色体;１对为着丝粒区有带纹的近中着丝粒染色体。     

Chromosome homology and heterochromatin in goat,sheep and ox studied by banding techniques

Peripheral blood lymphocyte metaphase chromosomes of three Bovoidean species have been studied using Quinacrine fluorescence and Giemsa banding techniques to give Q-, G-, and C-banding patterns. Q- and G-banding characteristics, coupled with chromosome length, enabled all of the chromosomes in each of the chromosome complements to be clearly distinguished, although some difficulties were encountered with the very smallest chromosomes. A comparison of G-banding patterns between the species revealed a remarkable degree of homology of banding patterns. Each of the 23 different acrocentric autosomes of the domestic sheep (2n=54) was represented by an identical chromosome in the goat (2n=60) and the arms of the 3 pairs of sheep metacentric autosomes were identical matches with the remaining 6 goat acrocentrics. A similar interspecies homology was evident for all but two of the autosomes in the ox (2n=60). This homology between sheep metacentric and goat acrocentric elements confirms a previously suggested Robertsonian variation. The close homology in G-banding patterns between these related species indicates that the banding patterns are evolutionarily conservative and may be a useful guide in assessing interspecific relationships. —The centromeric heterochromatin in the autosomes of the three species was found to show little or no Q-or G-staining, in contrast to the sex chromosomes. This lack of centromeric staining with the G-technique (ASG) contrasts markedly with results obtained with other mammalian species. However, with the C-banding technique these regions show a normal intense Giemsa stain and the C-bands in the sex chromosomes are inconspicuous. The amount of centromeric heterochromatin in the sheep metacentric chromosomes is considerable less than in the acrocentric autosomes or in a newly derived metacentric element discovered in a goat. It is suggested that the pale G-staining of the centromeric heterochromatin in these species might be related to the presence of G-Crich satellite DNA.     

Cytology of the Cercopithecidae: the banding pattern of Cercopithecus nigroviridis Pocock 1907

In the present note, some preliminary results on the chromosomes of Cercopithecus nigroviridis are shown. In the two subjects studied a diploid number of 48 was found. The chromosomes were also treated by enzymatic digestion (trypsin treatment) and the results are visualized. These results seem to confirm a certain affinity between the banding pattern of the chromosomes of C. nigroviridis and the banding pattern of the chromosomes of Macaca mulatta. During the present study a very high percentage of association between the marked chromosome pair was also noticed.     

Chromosome banding and compaction

Summary We have described a characteristic substructure of mitotic chromosomes, the chromosomal unit fibre, with lengths about five times the length of the corresponding metaphase chromosomes and a uniform diameter of 0.4 m. In order to study the relationship of chromosome banding to chromosome compaction, methods have been devised to obtain banding patterns on chromosomal unit fibres, similar to G-band patterns of intact mitotic chromosomes. The total number of bands plus interbands per haploid human karyotype is estimated at about 3000. The banding pattern of chromosomal unit fibres indicates a certain resemblance to the normal G-banding pattern of human chromosomes even if the details indicate a short-range random distribution.     

Karyotype analysis of Nicotiana kawakamii Y. Ohashi using DAPI banding and rDNA FISH

Prometaphase cells were used to analyze the karyotype of Nicotiana kawakamii Y. Ohashi by means of sequential Giemsa/CMA/DAPI staining and multicolor fluorescence in situ hybridization with 5S and 18S rDNA. Observation of the DAPI-stained prometaphase spreads indicated that N. kawakamii had six pairs of large chromosomes, one pair of medium-sized chromosomes and five pairs of small chromosomes. The six pairs of large chromosomes possessed remarkable DAPI bands, and each could be identified from both the DAPI banding pattern and the length of the short arm. The DAPI banding pattern was approximately identical to the CMA and Giemsa banding patterns. Hybridization signals of the 18S rDNA probe were detected on two pairs of large chromosomes. In addition, two pairs of small chromosomes were identified based on the position of the 5S rDNA signals. An idiogram of N. kawakamii chromosomes was produced based on DAPI bands and rDNA loci. Received: 17 July 2000 / Accepted: 4 September 2000     

Heteromorphic sex chromosome system with an exceptionally large Y chromosome in a catfish Steindachneridion sp. (Pimelodidae)

The chromosomes and banding patterns of Steindachneridion sp., a large catfish (Pimelodidae), endemic to the Igua?u River, Brazil, were analyzed using conventional (C-, G-banding) and restriction enzyme banding methods. The same diploid number (2n = 56) as in other members of the genus and the family was found but the karyotype displayed an XX/XY sex chromosome system. The X chromosome was the smallest submetacentric, while the Y was the largest chromosome in the karyotype. Meiotic analysis showed 27 autosomal bivalents plus one heteromorphic XY bivalent during spermatogenesis. Sex chromosomes had no particular pattern after C-banding but G- and restriction enzyme bandings showed specific banding characteristics. The present finding represents the first report of a well-differentiated and uncommon sex chromosome system in the catfish family Pimelodidae.     

Chromosome organisation in the Australian plague locust,Chortoicetes terminifera

In Chortoicetes terminifera, G-banding, produced by the trypsin treatment of air-dried slides followed by Giemsa staining, leads to light staining gaps at the secondary constrictions on autosomal pair 6 and regions proximal to the centromere on the long arms of pair 4. The variable short arms of two of the three smallest pairs were usually flared and lightly stained after treatment. In contrast to the relatively minor response of the normal chromosome set to G-banding, the large supernumerary chromosomes of C. terminifera show a spectacular series of dark bands alternating with lightly stained gaps. Two G-band variants of the B-chromosome were found in a laboratory stock. These patterns of G-banding are discernable both at mitosis in adults and embryos of both sexes and at all stages of male meiosis. Some regions which are gaps after G-banding appear as dark bands after C-banding. Consequently the supernumerary chromosome is mainly darkly stained with C-banding. In addition the centromeres and some telomeres are C-banded along with narrow interstitial bands and polymorphic heterochromatic blocks. — C-banding was not always successful, the technique often yields a mixture of G- and C-banding. The disparity of banding between the normal complement and the B-chromosome implies that whatever the source of origin of the B it has undergone spectacular changes in organisation since its origin.     

The Basic Karyotype of Lotus tenuis C-banding and Feulgen Studies

The basic karyotype of L. tenuis is illustrated. The study ofFeulgen stained metaphases has shown that the chromosome complementconsists of four pairs of median chromosomes and two pairs ofsubmedian chromosomes. Two nucleolar constrictions characterizethe first homologous pair. The C-banding pattern includes largepericentric bands in each chromosome pair and a terminal bandin the short arm of chromosome 3 Lotus tenuis, chromosome morphology, C-banding