scholarly journals Mapping 18S ribosomal genes in fish of the genus Brycon (Characidae) by fluorescence in situ hybridization (FISH)

2000 ◽  
Vol 23 (1) ◽  
pp. 135-138 ◽  
Author(s):  
Adriane Pinto Wasko ◽  
Pedro Manoel Galetti Jr.
Keyword(s):  
In Situ Hybridization ◽  
Fluorescence In Situ Hybridization ◽  
Nucleolar Organizer ◽  
Rrna Genes ◽  
Nucleolar Organizer Regions ◽  
Single Chromosome ◽  
Individual Variations ◽  
18S Rrna Genes ◽  
High Level

The present study provides data on the nucleolar organizer regions (NORs) of seven Brycon species based on mapping of the 18S rRNA genes by fluorescence in situ hybridization (FISH). Fluorescent signals were observed on the telomere of the long arm of two large submetacentric chromosomes, thus confirming the number and location of NORs previously revealed by other classical cytogenetic techniques. Although there were no inter- or intra-individual variations in the number and location of the 18S loci, NOR size polymorphism was observed between homologous chromosomes. The clustering and conservation of NORs in a single chromosome pair indicates a high level of NOR stability among species of the genus Brycon.

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.

scholarly journals Cytogenetics of two sympatric Corydoras species (pisces, siluriformes, challichtyidae) of Southern Brazil

2006 ◽  
Vol 66 (1b) ◽  
pp. 191-198 ◽  
Author(s):  
R. F. Artoni ◽  
M. L. Terêncio ◽  
M. R. Vicari ◽  
M. C. A. Matiello ◽  
M. M. Cestari ◽  
...  
Keyword(s):  
In Situ Hybridization ◽  
Diploid Number ◽  
Constitutive Heterochromatin ◽  
Nucleolar Organizer ◽  
Nucleolar Organizer Regions ◽  
Great Similarity ◽  
Southern Brazil ◽  
Rdna Probe ◽  
Karyotypic Formula

Karyotypic data are presented for two sympatric Corydoras species of the Lagoa Dourada, namely, C. ehrhadti and C. paleatus, which are found in the upper Tibagi river basin (Ponta Grossa, State of Paraná, Brazil). The same diploid number and karyotypic formula were observed in both species/populations. A great similarity in the constitutive heterochromatin distribution and in the activity of nucleolar organizer regions was also found. The use of in situ hybridization with a fluorescent 18S rDNA probe allowed for the identification of the species/populations through the location of ribosomal sites.

scholarly journals Karyotype analysis and visualization of 45S rRNA genes using fluorescence in situ hybridization in aroids (Araceae)

2015 ◽  
Vol 9 (2) ◽  
pp. 145-160 ◽  
Author(s):  
Katrijn Van Laere ◽  
Prabhu Shankar Lakshmanan ◽  
Tom Eeckhaut ◽  
Johan Van Huylenbroeck ◽  
Erik Van Bockstaele ◽  
...  
Keyword(s):  
In Situ Hybridization ◽  
Fluorescence In Situ Hybridization ◽  
Karyotype Analysis ◽  
Rrna Genes

Physical mapping of 45S rRNA genes in Cucumis species by fluorescence in situ hybridization

1999 ◽  
Vol 77 (3) ◽  
pp. 389-393 ◽  
Author(s):  
Jin-Feng Chen ◽  
Jack E Staub ◽  
Jeffrey W Adelberg ◽  
Jiming Jiang
Keyword(s):  
In Situ Hybridization ◽  
Fluorescence In Situ Hybridization ◽  
Cucumis Sativus ◽  
Rrna Genes ◽  
Phylogenetic Distance ◽  
Rdna Sites ◽  
Cucumis Species ◽  
Cucumis Hystrix ◽  
26S Rrna

The chromosomal locations of the genes coding for the 18S-5.8S-26S rRNA was investigated in Cucumis species using fluorescence in situ hybridization. Cucumber (Cucumis sativus L., 2n = 2x = 14) possesses four pairs of rDNA loci that were mapped to chromosomes 1C, 2C, 4C, and 7C. The distinctive hybridization sites of the 18S-5.8S-26S rRNA genes provide several useful cytogenetic markers for identification of chromosomes in C. sativus. The 18S-5.8S-26S rDNA genes have also been detected on two chromosome pairs, one major and one minor pair of loci, in melon (Cucumis melo L., 2n = 2x = 24) and on three pairs of Cucumis hystrix Chakr. chromosomes. The different number and pattern of rDNA sites is consistent with the hypothesis that considerable phylogenetic distance exists among these species.Key words: fluorescence in situ hybridization, 45S rRNA gene, cytogenetics, Cucumis sativus, Cucucmis melo, Cucumis hystrix.

Chromosomal mapping of mouse 5S rRNA genes by direct R-banding fluorescence in situ hybridization

1994 ◽  
Vol 66 (4) ◽  
pp. 246-249 ◽  
Author(s):  
Y. Matsuda ◽  
K. Moriwaki ◽  
V.M. Chapman ◽  
Y. Hoi-Sen ◽  
J. Akbarzadeh ◽  
...  
Keyword(s):  
In Situ Hybridization ◽  
Fluorescence In Situ Hybridization ◽  
5S Rrna ◽  
Chromosomal Mapping ◽  
Rrna Genes ◽  
5S Rrna Genes

scholarly journals α-Proteobacterial Symbionts of Marine Bryozoans in the Genus Watersipora

2006 ◽  
Vol 73 (1) ◽  
pp. 303-311 ◽  
Author(s):  
Christine M. Anderson ◽  
Margo G. Haygood
Keyword(s):  
Phylogenetic Analysis ◽  
In Situ Hybridization ◽  
16S Rrna ◽  
Fluorescence In Situ Hybridization ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Bacterial Symbionts ◽  
California Coast ◽  
Specific Fluorescence

ABSTRACT Bacterial symbionts that resembled mollicutes were discovered in the marine bryozoan Watersipora arcuata in the 1980s. In this study, we used PCR and sequencing of 16S rRNA genes, specific fluorescence in situ hybridization, and phylogenetic analysis to determine that the bacterial symbionts of “W. subtorquata” and “W. arcuata” from several locations along the California coast are actually closely related α-Proteobacteria, not mollicutes. We propose the names “Candidatus Endowatersipora palomitas” and “Candidatus Endowatersipora rubus” for the symbionts of “W. subtorquata” and “W. arcuata,” respectively.

Chromosomal and genomic organization of Ty1-copia-like retrotransposon sequences in the genus Avena

Genome ◽  
1996 ◽  
Vol 39 (2) ◽  
pp. 410-417 ◽  
Author(s):  
A. Katsiotis ◽  
T. Schmidt ◽  
J. S. Heslop-Harrison
Keyword(s):  
In Situ Hybridization ◽  
Repetitive Sequence ◽  
Genomic Library ◽  
Nucleolar Organizer ◽  
Nucleolar Organizer Regions ◽  
Reaction Products ◽  
D Genome ◽  
Avena Species ◽  
Copy Numbers

A cloned repetitive sequence, pAvKB30, obtained from an Avena vaviloviana (AB genome) genomic library, along with two polymerase chain reaction products derived from the conserved region of the reverse transcriptase (RT) gene of retrotransposons, were characterized molecularly and cytologically. The cloned DNA fragment was a dispersed repeat present in all Avena species used in this study (A. strigosa, A. clauda, A. vaviloviana, A. magna, and A. sativa). The fragment was sequenced (210 bp) and found to be 69.5% homologous to part of WIS-2-1A, and 60.5% homologous to the leader sequence of BARE-1; both of these elements have been characterized as Ty1-copia-like retrotransposons in wheat and barley, respectively. In situ hybridization of pAvKB30 to diploid, tetraploid, and hexaploid oat species revealed that the probe is present on both arms of all chromosomes (A, B, C, and D genomes) but is excluded from their centromeric and nucleolar organizer regions. By using double in situ hybridization in hexaploid A. sativa (ACD genome), pAvKB30 was found to be present in lower copy numbers in C-genome chromosomes compared with A- and D-genome chromosomes. Furthermore, under low stringency conditions, pAvKB30 hybridized on Southern blots containing barley, wheat, rye, and Arrhenatherum DNA. However, under high stringency conditions, it hybridized only on Arrhenatherum DNA, which is considered to be the genus most closely related to Avena. All Avena species included in this study yielded a PCR product when the primers from the RT domain of retrotransposons were used. Two products, rtA, obtained by using A. strigosa (As genome) as template, and rtC, obtained by using A. clauda (Cp genome) as template, gave Southern and in situ hybridization results similar to pAvKB30, but each was more abundant in its genome of origin. Key words : genomes, oats, in situ hybridization, translocations, repetitive sequence.

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