Q-banding Patterns Research Articles

The G- and Q-band karyotype of Böhm's or Grant's zebra (Equus burchelli böhmi).

The modal chromosome number of Bohm's zebra (Equus burchelli bohmi) is 44. One female and one male were investigated. The autosomes were constituted by 12 pairs of metacentric, four pairs of submetacentric, one pair of subtelocentric and four pairs of acrocentric chromosomes. All the chromosomes were identified by the G- and Q-banding patterns, except two small acrocentric pairs which did not show bands. The smallest metacentric pair had indefinite satellites. In pair No. 18 one of the chromosomes had a short arm, the homologue was acrocentric. The X chromosome was submetacentric. It was the fifth longest chromosome and constituted 5.8 % of the female chromosome complement. The Y chromosome was the smallest metacentric chromosome and constituted about 1 % of the female chromosome complement. The G- and Q-banding patterns of the chromosomes were identical. A G-band diagram, an idiogram and G- and Q-band karyotypes are presented.

Chromosomes of malignant lymphomas. Studies in short-term cultures from lymph nodes of twenty cases

The chromosomes were studied in 20 cases of malignant lymphoma, including 9 cases of Hodgkin's disease (HD), 6 lymphosarcomas (LS), 2 reticulosarcomas (RS), 1 follicular lymphoma, 1 atypical lymphoma and 1 chronic lymphocytic leukemia (CLL). Seven of the 20 lymphomas were analyzed with a modified Q-banding technique, 1 of them also with orcein staining, as were the other 13 lymphomas. Exclusively normal karyotype was found in 4 HD, 2 LS. 1 RS and the CLL. The atypical lymphoma was hypodiploid, all the others were in the diploid range with variation towards hyperdiploidy, in 1 HD even towards hypotriploidy. Numeric variation among normal chromosomes involved especially C and E group chromosomes. Marker chromosomes were observed in 8 cases. The isochromosome markers found in 6 cases strongly indicated nonrandomness in the karyotypic variation. The Q-band patterns of some markers were represented diagrammatically by the densitometric computer method worked out by the authors.

Heterochromatin variation inOziroë argentinensis(Hyacinthaceae) revealed by florescent banding

Previous studies in Oziroë argentinensis (Lillo et Hauman) Speta, have showed variation of heterochromatic regions between and within different populations of the species. In this study, were examined the heterochromatic regions of nine individuals obtained by vegetative propagation from a single plant in an attempt to determine possible modifications of the heterochromatin distribution after 14 years. The analyzed individuals have not showed differences in chromosome number and karyotype formulae respect to the parental plant. However, the Q-banding technique revealed a wide variation in number, position and size of the heterochromatic regions. The number of heterochromatic regions ranged between 11 and 15, differing from the parental plant that presented 14. The total amount of heterochromatin ranged between 6.25 μm and 13.5 μm, which represent approximately 5.34 % and 8.99 of the total karyotype length. Likewise, the distribution of the heterochromatic regions was considerably different in all the studied specimens, due to which has been not found two or more individuals with the same Q-banding pattern. The wide variation of the heterochromatic regions observed in this species could be explained through different mechanisms, such as tandem duplications, saltatory amplification and somatic cross-over.

Multiple origins of tetraploid taxa in the Eurasian Bufo viridis subgroup

We used Q-banding and analyzed nucleolar organizing regions (NORs) to study the cytogenetic evolution of tetraploids within the Palearctic Bufo viridis subgroup, the only known amphibian complex comprising di-, tri- and tetraploid bisexually reproducing taxa. We examined three diploid (2n) nominal taxa (Bufo viridis viridis, B. v. turanensis, B. v. kermanensis) from five Eurasian localities and six tetraploid (4n) nominal taxa (B. oblongus, B. o. danatensis, B. pewzowi pewzowi, B. p. taxkorensis, B. p. unicolor, B. p. strauchi) from eight Central Asian localities. Homeologous chromosomes of 2n and 4n toads exhibit a similar morphology. Silver-staining and in situ hybridization revealed terminal NORs in the long arms of chromosomes 6 in all 2n but in only two out of four chromosomes 6 in all 4n taxa. Q-banding and a rapidly evolving mitochondrial marker suggest at least two origination events for Asian 4n toads: "Western Central Asian tetraploids" (B. oblongus Nikolsky, 1896) exhibit distinct differences within some chromosome quartets, which are divisible into pairs of chromosomes and may be allopolyploid. In contrast, "Central Asian tetraploids" (B. pewzowi Bedriaga, 1898) showed homogenous Q-banding patterns within each quartet, suggesting autopolyploidy. In Northeastern Iran, we discovered a zone of either common ancestry or hybridization of 2n and Western Central Asian 4n toads. This raises intriguing questions about how diploid and tetraploid taxa may evolve by exchanging genetic material.

Comparisons of G-Banding Patterns in Six Species of the Poaceae

Clear G-banding patterns have been obtained in the chromosomes of Hordeum vulgare, Aegilops squarrosa, Oryza sativa, Sorghum vulgare, Setaria italica, and Zea maysby combining an improved slide preparation technique and the ASG (Acetic acid/Saline/Giemsa) method. All species examined show multiple, closely adjacent bands all along their G-banded chromosomes. G-banding patterns identified homologous and differentiated nonhomologous chromosomes. In G-banding patterns, barley and Ae. squarrosa are more similar, but they are more different from rice, sorghum, millet, and maize, which are more similar. Q-banding was performed in Zea mays with quinacrine mustard. Except for very few bands, Q-banding patterns corresponded to G-banding patterns. The similarities of G-banding patterns in plants and mammals, consistency of relationships among experimental species as demonstrated by both G-banding of chromosomes and classic systematization, and the techniques of G-banding in plants are discussed.

A proposed nomenclature of the domestic cat karyotype.

High-resolution G- and Q-band patterns of cat (Felis catus) prometaphase chromosomes with more than 450 numbered bands are presented. This number represents approximately twice the number of bands per haploid set exhibited by feline chromosomes at mid-metaphase. A diagrammatic representation of G-banded cat chromosomes has already been described (O'Brien and Nash, 1982); however, precise numbering of bands and landmarks, as in the human karyotype and in the karyotypes of other domestic and laboratory animals, has not yet been available for the domestic cat karyotype, except for the RBG-banded ideograms constructed by Shibasaki et al. (1987) and Rønne and Storm (1995). In this report, we propose a numbering system for the G-banded ideogram reported previously (O'Brien and Nash, 1982) and an extended ideogram at the high-resolution level (473 numbered bands) as a contribution to the future standardization of the feline karyotype.

Mapping of a linkage group to the last bovine chromosome (BTA27) without an assignment.

Bovine genome maps are supported by three types of data: synteny, linkage, and cytogenetic information. These sources of information are gradually being integrated into a comprehensive genome map. Large genomic clones containing microsatellites have been used for the integration of different information in cattle. Polymorphic microsatellites within large genomic clones allow simultaneous fluorescent in situ hybridization (FISH) and genetic mapping (Solinas Toldo et al. 1993). We report the mapping of a lambda clone to Chromosome (Chr) 27, the last bovine chromosome without an assignment. This assignment anchors the unassigned linkage group B (Bishop et al. 1994), since the mapped lambda clone contains the BM203 microsatellite. A bovine genomic library (lambda EMBL3; Clontech Laboratory Inc., Palo Alto Calif.) was screened with the BM203 primers (Bishop et al. 1994) by a modified iterative screening method (Israel 1993; T.P.L. Smith, unpublished). The initial screening of approximately 300,000 plaque forming units was aliquoted into 48 pools and yielded two positive pools. A single pool was selected based upon the amount of amplified product and was aliquoted into 48 equal fractions. Three more rounds of screening and diluting of the positive pools were performed before the final pool was plated out on LB/agar plates. A single positive plaque was verified to contain the BM203 sequence and subsequently used for FISH. Fluorescent in situ hybridization of the BM203-containing lambda clone was carried out according to Solinas Toldo et al. (1995b) on metaphase spreads that were QFQ-banded prior to hybridization. Characteristic twin signals were consistently observed on a small chromosome that was provisionally identified as 27 based on its Q-banding pattern. Since the differentiation of

Diverse heterochromatin inLathyrus

SUMMARYConstitutive heterochromatin was observed in Lathyrus aphaca, L. cicera, L. odoratus, L. sativus and L. tingitanus. C-bands in L. odoratus and L. tingitanus are centromeric or proximal in location. In L. tingitanus, only the short arm of Chromosome 3 showed a large telomeric band; this was detected by C-banding following Q-banding but not in directly C-banded preparations. In L. odoratus, while most C-bands showed as positive Q-bands with enhanced fluorescence, small telomeric bands showed no differentiation with quinacrine. In L. tingitanus, constitutive heterochromatin showed two types of Q-band: one negative with quenched fluorescence at the centromeric regions of all the chromosomes and the other, positive with enhanced fluorescence at one or both sides of the negative bands. No other species of Lathyrus investigated showed discrete negative Q-bands. In L. aphaca and L. cicera. Q-banding patterns are characterized by large telomeric positively fluorescent bands on most members of each complemen...

Eigenanalysis of DAPI-stained chromosomes: tools and strategies toward computer-assisted analysis of FISH experiments.

The fluorescent dye 4',6-diamidino-2-phenylindole (DAPI) is widely used as a chromosome counterstain in fluorescence in situ hybridization (FISH) studies. It produces a Q-banding pattern that allows for both chromosome identification and the assignment of molecular probes to specific chromosome bands. Using a statistical procedure based on eigenanalysis, we have extracted features from digital images of DAPI-stained chromosomes and constructed prototypes of each of the 24 human chromosomes. The features of these prototypes are directly proportional, in intensity profile and band location, to those of real chromosomes. The prototype's intensity profile can be translated into cytogenetic bands to provide a computer-based strategy for chromosome mapping and analysis amenable to automation. Data presented here were obtained using images from the 24 human chromosomes and mouse X chromosome. Moreover, the same procedure is general and can be used for the analysis of chromosomes from other species, as well as with banding techniques other than those using DAPI.

Seven loci on human Chromosome 4 map onto sheep Chromosome 6: a proposal to restore the original nomenclature of this sheep chromosome

Seven new loci, casein alpha-S1 (CSN1S1), casein alpha-S2 (CSN1S2), casein beta (CSN2), the Hardy-Zuckerman 4 feline sarcoma viral (v-kit) oncogene homolog (KIT), albumin (ALB), phosphodiesterase cyclic GMP (rod receptor) beta polypeptide (PDEB), and complement component 1 (IF), were assigned to sheep Chromosome (Chr) 6 by Southern hybridization to a panel of chromosomally characterized sheep x hamster cell hybrids. By isotopic in situ hybridization, CSN2 was regionally localized to sheep Chr (OOV) 6q22-q31, anchoring this syntenic group of markers on to OOV6 and confirming its homology at a molecular and cytological level with cattle Chr 6. The assignment of these loci, from PDEB (located on human Chr 4p16.3) to IF (on HSA4q24-q25), and the observation that interleukin 2 (IL2, on HSA4q26-q27) and tryptophan 2,3-dioxygenase (TDO2, on HSA4q31) are not located on OOV6, is further evidence of the close evolutionary relationship of sheep and cattle and the conserved synteny in these species of this extensive region of human Chr 4. On the basis of this conserved synteny, and the similar G- and Q-banding patterns of this chromosome in cattle and sheep, we propose that this sheep chromosome be numbered as 6, not 4 as recommended by ISCNDA (1990).

A theoretical approach to chromosome banding pattern analysis.

Based on a schematic model of karyotype evolution, a new methodology for G-, R-, or Q-banding pattern analysis was investigated. Banding pattern analysis essentially depends on the unidirectional alteration and the randomness of the exchange sites of the AM-inversion. In karyotypes that evolved by AM-inversion and Robertsonian rearrangement, two matching patterns appear; (1) tandem and (2) complementary matching patterns. The former is characteristic of a single lineage sharing the same AM-inversions, and the latter appears in different lineages sharing different AM-inversions, by which it is theoretically possible to detect the ancestral karyotype and to reconstruct the karyotype phylogeny (cladogram). In contrast, the evolutionary pathway cannot always be perceived if karyotypes evolve only by Robertsonian rearrangement. The tandem matching pattern does not always mean tandem fusion, but can be interpreted as 'tandem fission' by a combination of AM-inversion and centric fission. Tandem fusion and MM-inversion often cause entangled matching patterns, and thus they interfere with banding pattern analysis. Some methodological problems inherent in the conventional banding pattern analysis are highlighted, and suggested that such problems can be minimized by using the karyograph method. The methodology of banding pattern analysis proposed in the present paper will be applicable for matching the chromosome map of genetic markers among different species.

Location of the mouse complement factor H gene (cfh) by FISH analysis and replication R-banding.

A technique for replication R- and G-banding of mouse lymphocyte chromosomes was developed, and the replication R-banding pattern was analyzed. Optimal banding patterns were obtained with thymidine- and BrdU-treatment of lymphocytes in the same cell cycle. This produced replication R-band patterns that were the complete reverse of the G-band patterns on all chromosomes. Replication R-banding methods can be used in conjunction with nonisotopic, fluorescence in situ hybridization (FISH) to localize cloned probes to specific chromosomal bands on mouse chromosomes. with these methods the mouse complement factor H gene (cfh) was localized to the terminal portion of the F region of Chromosome 1. Q-banding patterns were also obtained by the replication R-banding method and may be useful for rapid identification of each chromosome.

Mapping small DNA sequences by fluorescence in situ hybridization directly on banded metaphase chromosomes.

A procedure for mapping small DNA probes directly on banded human chromosomes by fluorescence in situ hybridization has been developed. This procedure allows for the simultaneous visualization of banded chromosomes and hybridization signal without overlaying two separate photographic images. This method is simple and rapid, requires only a typical fluorescence microscope, has proven successful with DNA probes as small as 1 kilobase, is applicable for larger probes, and will greatly facilitate mapping the vast number of probes being generated to study genetic disease and define the human genome. Human metaphase chromosomes were prepared from phytohemagglutinin-stimulated lymphocyte cultures synchronized with bromodeoxyuridine and thymidine. Probes were labeled with biotin-dUTP, and the hybridization signal was amplified by immunofluorescence. Chromosomes were stained with both propidium iodide and 4',6-diamidino-2-phenylindole (DAPI), producing R- and Q-banding patterns, respectively, allowing unambiguous chromosome and band identification while simultaneously visualizing the hybridization signal. Thirteen unique DNA segments have been localized to the long arm of chromosome 11 by using this technique, and localization of 10 additional probes by using radioactive in situ hybridization provides a comparison between the two procedures. These DNA segments have been mapped to all long-arm bands on chromosome 11 and in regions associated with neoplasias and inherited disorders.

Chromosome Analysis of Canine Transmissible Sarcoma Cells

The chromosomal banding patterns of canine transmissible sarcoma (CTS) cells were analyzed and compared to those of normal canine cells with four banding techniques. In addition, N-myc and N-ras oncogenes on the chromosomes of the CTS cells were investigated by the in situ hybridization method. The modal chromosome number of the CTS cells was 58:17 metacentrics and 41 acrocentrics. Based on their G- and Q-banding patterns most of the chromosomes of the CTS cells were present in normal cells except for the second largest metacentric chromosomes. It was considered that the metacentric chromosomes of the CTS cells results from Robertsonian translocation of normal chromosomes. The long arm of the second largest metacentric element of the CTS cells was stained negatively by the Q-banding technique. The C-band was found on the long arm of the second largest metacentric element and three pairs of N-bands were recognized in the same region. It was suggested that this amplification of N-bands enhanced tumorigenic properties in the CTS. No N-myc or N-ras oncogenes were detected on chromosomes of the CTS cells by the in situ hybridization method.

Q-band chromosomal polymorphisms in arctic char (Salvelinus alpinus)

Stock-specific variation in the number and location of quinacrine-staining chromosomal bands was found in North American and European stocks of arctic char (Salvelinus alpinus). The mean number of bands per genome varied from 5.8 ± 5.3 in the Northwest Territories stock to 15.4 ± 2.1 in the Scottish stock. These bands appear to represent a subset of heterochromatin since they stain darkly with the C-band technique. Since the four stocks examined were each distinguishable on the basis of their Q-band patterns, these chromosome markers should be useful in genetic comparisons between different arctic char stocks and populations.Key words: Q banding, chromosomes, polymorphisms, arctic char, Salvelinus alpinus.

The banding patterns of normal canine chromosomes.

The chromosomal banding patterns of canine normal chromosome were analyzed by G-, Q-, C- and N-banding techniques. The chromosomes of canine normal lymphocytes consisted of 38 acrocentric autosome pairs and X-, Y-metacentric sex chromosomes. Their G- and Q-banding patterns corresponded to the those reported by Manolache et al. in 1976. C-bands of chromosomes were found on the centromeric regions of the 7th, 26th, 34th, 35th, 37th and 38th pairs of chromosomes. In addition, N-bands whose location had not been confirmed until now were recognized on the telomitic regions of the 7th, 9th and 22nd pairs of chromosomes.

Restriction endonuclease digestion and chromosome banding in the mosquito, Culiseta longiareolata (Diptera: Culicidae).

Fixed chromosomes of the mosquito, Culiseta longiareolata (2n = 6) were treated in situ with nine restriction endonucleases and stained with ethidium bromide or Giemsa. All the heterochromatic regions were apparently protected from digestion by all enzymes except Mbo I. This enzyme selectively digested one of the three types of heterochromatin present in the species. Staining with the fluorochrome quinacrine after enzyme treatment produced a standard Q-banding pattern or a Hoechst 33258-like pattern, depending on the enzyme. These results confirmed: (a) the presence of three types of heterochromatic containing different DNA fractions in the chromosomes of this species, (b) restriction enzymes accessibility to the DNA of heterochromatin regions, and (c) the selective cleavage of particular DNA fractions without DNA removal. Moreover, quinacrine staining after enzyme digestion proved useful in detecting differential activity among enzymes which produced the same banding pattern with standard dyes.

Mechanisms of quinacrine binding and fluorescence in nuclei and chromosomes.

The mechanisms has been investigated whereby quinacrine binds to the DNA of nuclei and chromosomes in cytological preparations fixed in methanol-acetic acid. A variety of evidence is consistent with the idea that the quinacrine binds by intercalation. This is supported by a high value for the affinity of quinacrine for DNA, together with a saturation value of 0.2 quinacrine molecules/nucleotide; binding in the presence of strong salt solutions; and inhibition of fluorescence and banding by denaturation or depurination of DNA. At high quinacrine concentrations, weak binding of quinacrine to nuclei and chromosomes also occurs, but this is not relevant to the production of strong fluorescence or Q-banding patterns. A number of factors were tested which might have affected quinacrine fluorescence and banding. These included: pH; blocking protein amino groups by acetylation or benzoylation; introduction of hydrophobic groups by benzoylation; and dephosphorylation. All these treatments were without effect. However, comparison of the quinacrine fluorescence of human and onion nuclei, which differ substantially in the base composition of their DNA, shows that quinacrine fluorescence can be enhanced in cytological preparations by AT-rich DNA.

Chromosomal homologies of the genera Vespertilio, Plecotus and Barbastella (Chiroptera: Vespertilionidae)

Q-banding (and partly G-banding) patterns of chromosomes were studied in three species of vespertilionid bats: Vespertilio murinus, Plecotus auritus and Barbastella barbastellus. The chromosomes of these species were identified and compared on the basis of the G-band diagram of Bickham (Cytologia 44, 1979) for the genus Myotis. The additional metacentric chromosomes which Vespertilio shows as compared to Myotis, differ in arm arrangements from those found in Plecotus and Barbastella. Banding patterns of P. auritus and B. barbastellus are nearly identical. It is remarkable that the smallest metacentric chromosome of P. auritus differs clearly in its banding pattern from that of the American P. townsendi. The significance of the results obtained for the systematic position of these species is discussed.

Simultaneous Detection of SCE and Q-bands on human chromosomes by a double-staining technique

Human lymphocytes were cultured for two cell cycles in the presence of bromodeoxyuridine (BrdU), and the resulting metaphase chromosomes were first stained with quinacrine mustard (QM) and then, immediately afterwards, with Hoechst 33258, without any intermediate destaining. Both Q-banding patterns and sister chromatid differential staining were photographed subsequently on the same metaphase using two different filter blocks of the fluorescence microscope.