Cytological and molecular evidence of deletion of ribosomal RNA genes in chromosome 6 of barley (Hordeum vulgare)

Genome ◽  
1994 ◽  
Vol 37 (3) ◽  
pp. 419-425 ◽  
Author(s):  
K. Gecheff ◽  
T. Hvarleva ◽  
S. Georgiev ◽  
T. Wilkes ◽  
A. Karp
Keyword(s):  
In Situ Hybridization ◽  
Organizer Region ◽  
Nucleolus Organizer Region ◽  
Molecular Techniques ◽  
The Other ◽  
Rrna Genes ◽  
Molecular Evidence ◽  
Chromosome 6 ◽  
Giemsa Banding

The barley chromosomal mutant T-35, in which only one pair of satellite chromosomes is apparent, was analyzed using a range of cytological and molecular techniques. Using conventional Feulgen staining, Giemsa and silver banding, in situ hybridization, and Southern blot analysis, unequivocal cytological and molecular evidence was obtained that T-35 is a homozygous deletion of rRNA genes residing in the nucleolus organizer region (NOR) of chromosome 6. According to the criteria of arm ratio and Giemsa-banding pattern of this chromosome, the deletion involved the whole NOR, one of the breakpoints being localized in the short arm proximally to the NOR-associated heterochromatic band, the other probably in the satellite of the chromosome. As a result of this deletion, an increased activity of the rRNA genes (as indicated by the size of the silver bands) on the other NOR-bearing chromosome (chromosome 7) was observed. The possible reasons for this phenomenon are discussed.Key words: barley, nucleolar organizing region, deletion, silver and Giemsa banding, in situ hybridization.

Primer-induced in situ hybridization to plant chromosomes

Genome ◽  
1993 ◽  
Vol 36 (5) ◽  
pp. 815-817 ◽  
Author(s):  
S. Abbo ◽  
T. E. Miller ◽  
I. P. King
Keyword(s):  
In Situ Hybridization ◽  
Mitotic Chromosome ◽  
Organizer Region ◽  
Nucleolus Organizer Region ◽  
Nucleolus Organizer ◽  
Hybridization Technique ◽  
Plant Chromosomes ◽  
Secale Cereale L ◽  
Future Potential

Primer-induced in situ hybridization of high copy sequences was used successfully on rye mitotic chromosome spreads. Nucleolus organizer sequences were detected in rye, and the pattern obtained was in full agreement with previously reported results by conventional in situ hybridization. The future potential of the primer-induced in situ hybridization technique is briefly discussed.Key words: primer-induced in situ hybridization, rye (Secale cereale L.), nucleolus organizer region.

Detection of ribosomal DNA sites in lentil and chickpea by fluorescent in situ hybridization

Genome ◽  
1994 ◽  
Vol 37 (4) ◽  
pp. 713-716 ◽  
Author(s):  
S. Abbo ◽  
T. E. Miller ◽  
S. M. Reader ◽  
R. P. Dunford ◽  
I. P. King
Keyword(s):  
In Situ Hybridization ◽  
Fluorescent In Situ Hybridization ◽  
Lens Culinaris ◽  
Organizer Region ◽  
Nucleolus Organizer Region ◽  
Nucleolus Organizer ◽  
Rdna Sites ◽  
In The Wild ◽  
Wild Lentil

Hybridization sites of an rDNA probe coding for the 18S, 5.8S, and 26S genes were detected on lentil and chickpea somatic chromosomes using fluorescent in situ hybridization. One pair of hybridization sites was detected in cultivated lentil Lens culinaris L. and wild lentil L. orientalis (Boiss.) Hand.-Mazz., and in both the hybridization sites of the ribosomal probe correspond to the secondary constriction. In cultivated chickpea Cicer arietinum three pairs of rDNA sites were detected and in the wild C. reticulatum two pairs were detected. The karyotypic relationship between the cultivated C. arietinum and its wild progenitor C. reticulatum is discussed.Key words: chickpea, lentil, rDNA sites, nucleolus organizer region, fluorescent in situ hybridization, primer-mediated in situ hybridization.

Fluorescent in situ hybridization shows DIPLOSPOROUS located on one of the NOR chromosomes in apomictic dandelions (Taraxacum) in the absence of a large hemizygous chromosomal region

Genome ◽  
2014 ◽  
Vol 57 (11/12) ◽  
pp. 609-620 ◽  
Author(s):  
Radim J. Vašut ◽  
Kitty Vijverberg ◽  
Peter J. van Dijk ◽  
Hans de Jong
Keyword(s):  
In Situ Hybridization ◽  
Fluorescent In Situ Hybridization ◽  
Genetic Model ◽  
Organizer Region ◽  
Nucleolus Organizer Region ◽  
Nucleolus Organizer ◽  
Artificial Chromosomes ◽  
Chromosomal Position ◽  
Apomictic Species

Apomixis in dandelions (Taraxacum: Asteraceae) is encoded by two unlinked dominant loci and a third yet undefined genetic factor: diplosporous omission of meiosis (DIPLOSPOROUS, DIP), parthenogenetic embryo development (PARTHENOGENESIS, PAR), and autonomous endosperm formation, respectively. In this study, we determined the chromosomal position of the DIP locus in Taraxacum by using fluorescent in situ hybridization (FISH) with bacterial artificial chromosomes (BACs) that genetically map within 1.2–0.2 cM of DIP. The BACs showed dispersed fluorescent signals, except for S4-BAC 83 that displayed strong unique signals as well. Under stringent blocking of repeats by C0t-DNA fragments, only a few fluorescent foci restricted to defined chromosome regions remained, including one on the nucleolus organizer region (NOR) chromosomes that contains the 45S rDNAs. FISH with S4-BAC 83 alone and optimal blocking showed discrete foci in the middle of the long arm of one of the NOR chromosomes only in triploid and tetraploid diplosporous dandelions, while signals in sexual diploids were lacking. This agrees with the genetic model of a single dose, dominant DIP allele, absent in sexuals. The length of the DIP region is estimated to cover a region of 1–10 Mb. FISH in various accessions of Taraxacum and the apomictic sister species Chondrilla juncea, confirmed the chromosomal position of DIP within Taraxacum but not outside the genus. Our results endorse that, compared to other model apomictic species, expressing either diplospory or apospory, the genome of Taraxacum shows a more similar and less diverged chromosome structure at the DIP locus. The different levels of allele sequence divergence at apomeiosis loci may reflect different terms of asexual reproduction. The association of apomeiosis loci with repetitiveness, dispersed repeats, and retrotransposons commonly observed in apomictic species may imply a functional role of these shared features in apomictic reproduction, as is discussed.

Physical mapping of the 5S rRNA multigene family in 6x triticale and rye: identification of a new rye locus

Genome ◽  
1995 ◽  
Vol 38 (3) ◽  
pp. 623-626 ◽  
Author(s):  
Angeles Cuadrado ◽  
Nicolas Jouv ◽  
J. S. Heslop-Harrison
Keyword(s):  
In Situ Hybridization ◽  
Multigene Family ◽  
The Other ◽  
5S Rrna ◽  
Rrna Genes ◽  
Hexaploid Triticale ◽  
Selected Lines ◽  
Secale Cereale L ◽  
5S Rrna Genes

In situ hybridization was used to physically map the 5S rRNA multigene family in three selected lines of hexaploid triticale and five lines of diploid rye. Using this technique, evidence for a new locus on the 3RS arm of the three triticale lines was first obtained, as well as confirmation of the presence of 5S rRNA loci on wheat and rye chromosomes of homoeologous groups 1 and 5. The new locus on the 3RS arm was confirmed in two lines of rye, Secale cereale L., although it was not present in the other rye varieties studied. We propose that the new 5S rRNA locus be referred to as 5SDna-R3.Key words: in situ hybridization, FISH, Secale, triticale, 5S rRNA genes.

scholarly journals Comparative Distribution of Repetitive Sequences in the Karyotypes of Xenopus tropicalis and Xenopus laevis (Anura, Pipidae)

Genes ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 617
Author(s):  
Álvaro S. Roco ◽  
Thomas Liehr ◽  
Adrián Ruiz-García ◽  
Kateryna Guzmán ◽  
Mónica Bullejos
Keyword(s):  
In Situ Hybridization ◽  
Xenopus Laevis ◽  
Organizer Region ◽  
Repetitive Sequences ◽  
Nucleolus Organizer Region ◽  
Nucleolus Organizer ◽  
Repeated Sequences ◽  
Xenopus Tropicalis ◽  
Model Organisms

Xenopus laevis and its diploid relative, Xenopus tropicalis, are the most used amphibian models. Their genomes have been sequenced, and they are emerging as model organisms for research into disease mechanisms. Despite the growing knowledge on their genomes based on data obtained from massive genome sequencing, basic research on repetitive sequences in these species is lacking. This study conducted a comparative analysis of repetitive sequences in X. laevis and X. tropicalis. Genomic in situ hybridization (GISH) and fluorescence in situ hybridization (FISH) with Cot DNA of both species revealed a conserved enrichment of repetitive sequences at the ends of the chromosomes in these Xenopus species. The repeated sequences located on the short arm of chromosome 3 from X. tropicalis were not related to the sequences on the short arm of chromosomes 3L and 3S from X. laevis, although these chromosomes were homoeologous, indicating that these regions evolved independently in these species. Furthermore, all the other repetitive sequences in X. tropicalis and X. laevis may be species-specific, as they were not revealed in cross-species hybridizations. Painting experiments in X. laevis with chromosome 7 from X. tropicalis revealed shared sequences with the short arm of chromosome 3L. These regions could be related by the presence of the nucleolus organizer region (NOR) in both chromosomes, although the region revealed by chromosome painting in the short arm of chromosome 3L in X. laevis did not correspond to 18S + 28S rDNA sequences, as they did not colocalize. The identification of these repeated sequences is of interest as they provide an explanation to some problems already described in the genome assemblies of these species. Furthermore, the distribution of repetitive DNA in the genomes of X. laevis and X. tropicalis might be a valuable marker to assist us in understanding the genome evolution in a group characterized by numerous polyploidization events coupled with hybridizations.

Sequential silver staining and in situ hybridization reveal a direct association between rDNA levels and the expression of homologous nucleolar organizing regions: a hypothesis for NOR structure and function

1998 ◽  
Vol 111 (10) ◽  
pp. 1433-1439
Author(s):  
F. Zurita ◽  
R. Jimenez ◽  
M. Burgos ◽  
R.D. de la Guardia
Keyword(s):  
Transcription Factors ◽  
In Situ Hybridization ◽  
Silver Staining ◽  
Organizer Region ◽  
Nucleolar Organizer ◽  
Interindividual Variation ◽  
Nucleolar Organizer Regions ◽  
Single Pair ◽  
Ribosomal Cistrons

We have developed a procedure for sequential silver staining and in situ hybridization to analyze the relationship between the amount of rDNA present in nucleolar organizer regions, as estimated by in situ hybridization, and their level of expression, as estimated by the silver signal. For simplicity we used cells from the insectivorous mole Talpa occidentalis, which have a single pair of nucleolar organizer regions in chromosome pair 3. The relative content of ribosomal cistrons was also related to the hierarchy of activation of the nucleolar organizer regions present in this chromosomal pair. Statistical analyses demonstrated that both the relative level of expression and the activation hierarchy depended mainly on the number of ribosomal cistrons in nucleolar organizer regions. We propose a functional two-step hypothesis, which is consistent with most known data concerning interchromosomal, intercellular and interindividual variation in a number of plant and animal species, including Talpa occidentalis. In step one, the first available transcription factors bind randomly to the ribosomal promoters, such that larger nucleolar organizer regions are more likely to recruit them. In the second step the remaining transcription factors are recruited in a cooperative way, thus completing activation of one nucleolar organizer region, before the next one becomes active.

Recovery of a telomere-truncated chromosome via a compensating translocation in maize

Genome ◽  
2011 ◽  
Vol 54 (3) ◽  
pp. 184-195 ◽  
Author(s):  
Robert T. Gaeta ◽  
Tatiana V. Danilova ◽  
Changzeng Zhao ◽  
Rick E. Masonbrink ◽  
Morgan E. McCaw ◽  
...  
Keyword(s):  
In Situ Hybridization ◽  
Fluorescent In Situ Hybridization ◽  
Transgene Expression ◽  
De Novo ◽  
Extra Chromosome ◽  
Single Gene ◽  
B Chromosomes ◽  
Chromosome 1 ◽  
Chromosome 6

Maize-engineered minichromosomes are easily recovered from telomere-truncated B chromosomes but are rarely recovered from A chromosomes. B chromosomes lack known genes, and their truncation products are tolerated and transmitted during meiosis. In contrast, deficiency gametes resulting from truncated A chromosomes prevent their transmission. We report here a de novo compensating translocation that permitted recovery of a large truncation of chromosome 1 in maize. The truncation (trunc-1) and translocation with chromosome 6 (super-6) occurred during telomere-mediated truncation experiments and were characterized using single-gene fluorescent in situ hybridization (FISH) probes. The truncation contained a transgene signal near the end of the broken chromosome and transmitted together with the compensating translocation as a heterozygote to approximately 41%–55% of progeny. Transmission as an addition chromosome occurred in ~15% of progeny. Neither chromosome transmitted through pollen. Transgene expression (Bar) cosegregated with trunc-1 transcriptionally and phenotypically. Meiosis in T1 plants revealed eight bivalents and one tetravalent chain composed of chromosome 1, trunc-1, chromosome 6, and super-6 in diplotene and diakinesis. Our data suggest that de novo compensating translocations allow recovery of truncated A chromosomes by compensating deficiency in female gametes and by affecting chromosome pairing and segregation. The truncated chromosome can be maintained as an extra chromosome or together with the super-6 as a heterozygote.

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