Somatic cell cytology of the chromosome-eliminating, intergeneric hybrid Hordeum vulgare × Psathyrostachys fragilis

1984 ◽  
Vol 26 (4) ◽  
pp. 436-444 ◽  
Author(s):  
I. Linde-Laursen ◽  
R. von Bothmer
Keyword(s):  
Hordeum Vulgare ◽  
Metaphase Plate ◽  
Intergeneric Hybrid ◽  
Chromosome Elimination ◽  
Staining Intensity ◽  
Nucleolus Organizer ◽  
Common Mechanism ◽  
Banding Patterns ◽  
Nucleolus Organizer Regions ◽  
C Banding

In the hybrid Hordeum vulgare × Psathyrostachys fragilis the two genomes were differentiated (i) by length, the P. fragilis chromosomes being 31% longer than the H. vulgare chromosomes; (ii) by a difference in staining intensity of C-banded chromosomes (of possible use for exact localization of breakpoints), the H. vulgare chromosomes being the more heavily stained; (iii) by widely different C-banding patterns; and (iv) by the difference between N-banded H. vulgare and non-N-banded P. fragilis chromosomes. Only C-banding patterns identified each chromosome. Aneuploid cells had lost between one and five P. fragilis chromosomes. Loss of H. vulgare chromosomes is ascribed to squashing. No haploid H. vulgare cell was observed. The P. fragilis chromosomes were characterized by diminished centric constrictions, suppression of nucleolar constrictions, and nucleolus activity, i.e., differential amphiplasty, and generally a peripheral location on the metaphase plate. The same characteristics are normally observed in hybrids producing haploids H. vulgare, suggesting a common mechanism of chromosome elimination. Some cells had a side-by-side arrangement of genomes. The only effect of the hybrid condition on H. vulgare chromosomes was the formation of wider nucleolar constrictions and larger nucleolus organizer regions (NORs) than in parental H. vulgare, suggesting a compensational mechanism for nucleolus activity. The passage of H. vulgare chromosomes through the hybrid to the dihaploid did not influence chromosomal characteristics.Key words: Hordeum, Psathyrostachys, hybrids, elimination of chromosomes, banding.

Genetic and cytogenetic analyses of the A genome of Triticum monococcum. VI. Production and identification of primary trisomics using the C-banding technique

Genome ◽  
1990 ◽  
Vol 33 (4) ◽  
pp. 542-555 ◽  
Author(s):  
B. Friebe ◽  
N.-S. Kim ◽  
J. Kuspira ◽  
B. S. Gill
Keyword(s):  
Nucleolus Organizer ◽  
Triticum Monococcum ◽  
Banding Patterns ◽  
Primary Trisomics ◽  
Nucleolus Organizer Regions ◽  
C Banding ◽  
A Genome ◽  
Chromosome 5A ◽  
Triple Dose

Cytogenetic studies in Triticum monococcum (2n = 2x = 14) are nonexistent. To initiate such investigations in this species, a series of primary trisomics was generated from autotriploids derived from crosses between induced autotetraploids and diploids. All trisomics differed phenotypically from their diploid progenitors. Only two of the seven possible primary trisomic types produced distinct morphological features on the basis of which they could be distinguished. The chromosomes in the karyotype were morphologically very similar and could not be unequivocally identified using standard techniques. Therefore, C-banding was used to identify the chromosomes and trisomics of this species. Ag–NOR staining and in situ hybridization, using rDNA probes, were used to substantiate these identifications. A comparison of the C-banding patterns of the chromosomes of T. monococcum with those of the A genome in Triticum aestivum permitted identification of five of its chromosomes, viz., 1A, 2A, 3A, 5A, and 7A. The two remaining chromosomes possessed C-banding patterns that were not equivalent to those of any of the chromosomes in the A genome of the polyploid wheats. When one of these undesignated chromosomes from T. monococcum var. boeoticum was substituted for chromosome 4A of Triticum turgidum, it compensated well phenotypically and therefore genetically for the loss of this chromosome in the recipient species. Because this T. monococcum chromosome appeared to be homoeologous to the group 4 chromosomes of polyploid wheats, it was designated 4A. By the process of elimination the second undesignated chromosome in T. monococcum must be 6A. Analysis of the trisomics obtained led to the following conclusions. (i) Trisomics for chromosome 3A were not found among the trisomic lines analyzed cytologically. (ii) Primary trisomics for chromosomes 2A, 4A, 6A, and 7A were positively identified. (iii) Trisomics for the SAT chromosomes 1A and 5A were positively identified in some cases and not in others because of polymorphism in the telomeric C-band of the short arm of chromosome 1A. (iv) Trisomics for chromosome 7A were identified on the basis of their distinct phenotype, viz., the small narrow heads and small narrow leaves. Because rRNA hybridizes lightly to nucleolus organizer regions on chromosome 1A and heavily to nucleolus organizer regions on chromosome 5A, our results indicate that trisomics in line 50 carry chromosome 1A in triple dose and trisomics in lines 28 and 51 carry chromosome 5A in triplicate. Variable hybridization of the rDNA probe to nucleolus organizer regions on chromosomes in triple dose in lines 7, 20, and 28 precluded the identification of the extra chromosome in these lines. Cytogenetic methods for unequivocally identifying trisomics for chromosomes 1A and 5A are discussed. Thus six of the series of primary trisomics have been identified. Telotrisomic lines are also being produced.Key words: Triticum monococcum, trisomics, C-banding, Ag-NOR staining, in situ hybridization, rDNA probes, plant morphology.

Levels of conservation and variation of heterochromatin and nucleolus organizers in the Bovidae

1985 ◽  
Vol 27 (6) ◽  
pp. 665-682 ◽  
Author(s):  
B. Mayr ◽  
D. Schweizer ◽  
M. Mendelak ◽  
J. Krutzler ◽  
W. Schleger ◽  
...  
Keyword(s):  
Nucleolus Organizer ◽  
Centromeric Heterochromatin ◽  
Banding Patterns ◽  
X Chromosomes ◽  
Distamycin A ◽  
Nucleolus Organizer Regions ◽  
Standard Karyotype ◽  
Swamp Buffalo ◽  
High Degree ◽  
Nucleolus Organizers

Chromomycin A3 banding of the mitotic sets of 10 species of Bovidac (cattle, wisent, yak, banteng, gaur, red buffalo, swamp buffalo, sheep, mufflon, and goat) serves to demarcate both centromeric constitutive heterochromatin and R-banding patterns capable of identifying all the chromosomes within a given complement. In all species significant amounts of chromomycin-bright heterochromatin are present at the centromeres of all autosomes, though there was a high degree of intra- and inter-individual variation in the size of the heterochromatic blocks. Marked interspecies differences in the centromeric patterns were evident. The X chromosomes contained appreciable amounts of centromeric heterochromatin only in the two buffaloes. All the animals studied lacked distamycin A – diamidinophenylindole type heterochromatin. AgNO3 staining was applied sequentially to detect the location of active nucleolus organizer regions (NORs). The distribution of NORs was reasonably conservative in most of the species. An exceptional situation was found in the two buffaloes, where only one NOR pair matched with the standard karyotype of the Bovidae.Key words: heterochromatin, chromomycin A3 fluorescence, nucleolus organizers, Bovidae.

CONSERVATION OF NUCLEOLUS ORGANIZER REGIONS DURING EVOLUTION IN SHEEP, GOAT, CATTLE AND AOUDAD

1979 ◽  
Vol 21 (1) ◽  
pp. 1-8 ◽  
Author(s):  
L. M. Henderson ◽  
A. N. Bruère
Keyword(s):  
Ribosomal Dna ◽  
Bos Taurus ◽  
Centric Fusion ◽  
Nucleolus Organizer ◽  
Ovis Aries ◽  
Capra Hircus ◽  
Domestic Sheep ◽  
Banding Patterns ◽  
Nucleolus Organizer Regions ◽  
Ammotragus Lervia

There are ten nucleolus organizer regions (NORs) in domestic sheep (Ovis aries L.), cattle (Bos taurus L.), goat (Capra hircus L.) and aoudad (Ammotragus lervia Blyth) and these are located terminally on chromosomes with homologous G-banding patterns. The similarity in number of nucleolus organizer regions in these species may indicate that their ribosomal DNA regions are infrequently involved in exchange events which could lead to different numbers of active nucleolus organizer regions. Other possible explanations of the conservation of number of nucleolus organizer regions in these species are discussed. The homology of NOR location in these species supports the idea that the Bovidae karyotype tends to be fairly stable apart from changes due to centric fusion events.

scholarly journals Chromosome Banding in Amphibia. XXXIII. Demonstration of 5-Methylcytosine-Rich Heterochromatin in Anura

2016 ◽  
Vol 148 (1) ◽  
pp. 35-43
Author(s):  
Michael Schmid ◽  
Claus Steinlein
Keyword(s):  
Dna Sequences ◽  
Nucleolus Organizer ◽  
Major Influence ◽  
Banding Patterns ◽  
Nucleolus Organizer Regions ◽  
Experimental Parameters ◽  
Species Specific ◽  
Antibody Labeling ◽  
Chromosome Regions

An experimental approach using monoclonal anti-5-methylcytosine (5-MeC) antibodies and indirect immunofluorescence was elaborated for detecting 5-MeC-rich chromosome regions in anuran chromosomes. This technique was applied to mitotic metaphases of 6 neotropical frog species belonging to 6 genera and 4 families. The hypermethylation patterns were compared with a variety of banding patterns obtained by conventional banding techniques. The hypermethylated DNA sequences are species-specific and located exclusively in constitutive heterochromatin. They are found in centromeric, pericentromeric, telomeric, and interstitial positions of the chromosomes and adjacent to nucleolus organizer regions. 5-MeC-rich DNA sequences can be embedded both in AT- and GC-rich repetitive DNA. The experimental parameters that have major influence on the reproducibility and quality of the anti-5-MeC antibody labeling are discussed.

scholarly journals Karyotype, C-band and NOR phenotype of Anatolian endemic fish Squalius anatolicus (Bogutskaya, 1997) (Teleostei, Leuciscidae)

2021 ◽  
Vol 38 (3) ◽  
pp. 311-315
Author(s):  
Sevgi Ünal Karakuş ◽  
Muhammet Gaffaroğlu
Keyword(s):  
Chromosome Pair ◽  
Constitutive Heterochromatin ◽  
Nucleolus Organizer ◽  
Submetacentric Chromosome ◽  
Nucleolus Organizer Regions ◽  
C Banding ◽  
Nor Phenotype ◽  
Acrocentric Chromosomes ◽  
Endemic Fish ◽  
Lake Beysehir

The karyotype and distribution of constitutive heterochromatin and nucleolus organizer regions (NORs) of Anatolian leuciscine endemic to Lake Beysehir, Squalius anatolicus (Bogutskaya, 1997) were analyzed respectively using conventional Giemsa-staining, C-banding and Ag-impregnation. Diploid chromosome number was 2n = 50 and karyotype consisted of 7 pairs of metacentric, 13 pairs of submetacentric, 5 pairs of subtelo- to acrocentric chromosomes, NF value equaled 90. Heteromorphic elements indicating sex chromosomes were not detected. C-banding revealed clear pericentromeric constitutive heterochromatin blocks in several chromosomes. Ag-impregnation revealed the size heteromorphism of NORs that covered almost the entire short arms of the middle-sized submetacentric chromosome pair. The karyotype pattern and simple NOR phenotype of S. anatolicus are nearly identical with that found not only in Squalius species analyzed to date but also in many other representatives of the Eurasian leuciscine cyprinids, which indicates remarkable chromosome stasis in this leuciscid lineage.

scholarly journals Comparative cytogenetics of the ground frogs Eupsophus emiliopugini Formas, 1989 and E. vertebralis Grandison, 1961 (Alsodidae) with comments on their inter- and intraspecific chromosome differentiation

2020 ◽  
Vol 14 (1) ◽  
pp. 61-74
Author(s):  
Camila A. Quercia ◽  
Elkin Y. Suárez-Villota ◽  
Fausto Foresti ◽  
José J. Nuñez
Keyword(s):  
Gene Dosage ◽  
Chromosomal Rearrangements ◽  
Nucleolus Organizer ◽  
Rrna Gene ◽  
Comparative Cytogenetics ◽  
Nucleolar Dominance ◽  
Nucleolus Organizer Regions ◽  
C Banding ◽  
Chromosome Staining ◽  
Dominance Pattern

South American frogs of the genus Eupsophus Fitzinger, 1843 comprise 10 species. Two of them, Eupsophus vertebralis Grandison, 1961 and E. emiliopugini Formas, 1989 belong to the Eupsophus vertebralis group, exhibiting 2n = 28. Fundamental number differences between these species have been described using conventional chromosome staining of few specimens from only two localities. Here, classical techniques (Giemsa, C-banding, CMA3/DAPI banding, and Ag-NOR staining), and fluorescence in situ hybridization (FISH, with telomeric and 28S ribosomal probes), were applied on individuals of both species collected from 15 localities. We corroborate differences in fundamental numbers (FN) between E. vertebralis and E. emiliopugini through Giemsa staining and C-banding (FN = 54 and 56, respectively). No interstitial fluorescent signals, but clearly stained telomeric regions were detected by FISH using telomeric probe over spreads from both species. FISH with 28S rDNA probes and Ag-NOR staining confirmed the active nucleolus organizer regions signal on pair 5 for both species. Nevertheless, one E. emiliopugini individual from the Puyehue locality exhibited 28S ribosomal signals on pairs 4 and 5. Interestingly, only one chromosome of each pair showed Ag-NOR positive signals, showing a nucleolar dominance pattern. Chromosomal rearrangements, rRNA gene dosage control, mobile NORs elements, and/or species hybridization process could be involved in this interpopulation chromosomal variation.

A bread wheat (Triticum aestivum) × cultivated barley (Hordeum vulgare) hybrid with homoeologous chromosome pairing

1986 ◽  
Vol 28 (5) ◽  
pp. 777-782 ◽  
Author(s):  
G. S. Sethi ◽  
R. A. Finch ◽  
T. E. Miller
Keyword(s):  
Triticum Aestivum ◽  
Hordeum Vulgare ◽  
Chromosome Pairing ◽  
Chinese Spring ◽  
Nucleolus Organizer ◽  
Homoeologous Pairing ◽  
Homoeologous Chromosome ◽  
Partial Dominance ◽  
Nucleolus Organizer Regions ◽  
Homoeologous Chromosome Pairing

Triticum aestivum 'Chinese Spring' mutant ph1b lacking the major wheat homoeologous pairing prevention gene was pollinated with Hordeum vulgare line 'Tuleen 346,' a triple interchange homozygote with all chromosomes distinct from one another. Two wheat-like hybrids, one with 28 and one with 31 chromosomes, were produced. Homoeologous chromosome pairing occurred in the hybrids, but no evidence of interspecific chromosome pairing was observed. Both hybrids were sterile, but pollination of the 28-chromosome hybrid with 'Chinese Spring' pollen gave a few seeds. Within the F1 hybrids, chromosome numbers varied slightly, especially among pollen mother cells, and barley showed partial dominance of nucleolus organizer regions in somatic cells. The 31-chromosome hybrid was awned possibly indicating extra dosage of a homoeologous group-2 chromosome.Key words: wheat, barley, hybrid, homoeologous pairing.

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