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Phylogenetic analyses of Cladophora vagabunda (L.) C. Hoek (Cladophorales, Chlorophyta) from Brazil based on SSU rDNA sequences; Análises filogenéticas de Cladophora vagabunda (L.) C. Hoek (Cladophorales, Chlorophyta) do Brasil, baseada nas seqüências SSU rDNA

GESTINARI, Lísia Mônica de Souza; OLIVEIRA, Mariana Cabral de; MILSTEIN, Daniela; YONESHIGE-VALENTIN, Yocie; PEREIRA, Sonia Maria Barreto
Fonte: Sociedade Botânica de São Paulo Publicador: Sociedade Botânica de São Paulo
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
37.08%
The complete SSU rDNA was sequenced for 10 individuals of Cladophora vagabunda collected along the coast of Brazil. For C. rupestris (L.) Kütz. a partial SSU rDNA sequence (1634 bp) was obtained. Phylogenetic trees indicate that Cladophora is paraphyletic, but the section Glomeratae sensu lato including C. vagabunda from Brazil, Japan and France, C. albida (Nees) Kütz., C. sericea (Hudson) Kütz., and C. glomerata (L.) Kütz. is monophyletic. Within this group C. vagabunda is paraphyletic. The sequence identity for the SSU rDNA varied from 98.9% to 100% for the Brazilian C. vagabunda, and from 98.3% to 99.7% comparing the Brazilian individuals to the ones from France and Japan. Sequence identity of the Brazilian C. vagabunda to C. albida and C. sericea vary from 98.0% to 98.6%. The SSU rDNA phylogeny support partially the morphological characteristics presented by Brazilian populations of C. vagabunda. On the other hand, C. rupestris from Brazil does not group with C. rupestris from France, both sequences presenting only 96.9% of identity. The inclusion of sequences of individuals from Brazil reinforces the need of taxonomical revision for the genus Cladophora and for the complex C. vagabunda.; A seqüência completa do SSU rDNA foi obtida para 10 indivíduos de Cladophora vagabunda coletadas ao longo da costa do Brasil. Uma seqüência parcial do SSU rDNA (1634 bp) foi obtida para C. rupestris (L.) Kütz. As árvores filogenéticas indicam que Cladophora é parafilético...

Localization of ribosomal genes in three Pimelodus species (Siluriformes, Pimelodidae) of the São Francisco River: 5S genes as species markers and conservation of the 18S rDNA sites

GARCIA, Caroline; MOREIRA FILHO, Orlando
Fonte: Sociedade Brasileira de Genética Publicador: Sociedade Brasileira de Genética
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
36.93%
Pimelodidae is one of the most representative of Neotropical catfish families. However, these fish are still poorly studied in terms of cytogenetics, especially regarding the application of more accurate techniques such as the chromosomal localization of ribosomal genes. In the present work, fluorescent in situ hybridization with 5S and 18S rDNA probes was employed for rDNA site mapping in Pimelodus sp., P. fur and P. maculatus from the São Francisco River in the Três Marias municipality - MG. The results from the application of the 18S probe confirmed the previous data obtained by silver nitrate staining, identifying a simple nucleolar organizing region system for these species. However, the labeling results from the 5S rDNA probe demonstrated a difference in the number and localization of these sites between the analyzed species. The obtained data allowed inferences on the possible processes involved in the karyotypic evolution of this genus.; Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Karyotype characterization reveals an up and down of 45S and 5S rDNA sites in Crotalaria (Leguminosae-Papilionoideae) species of the section Hedriocarpae subsection Macrostachyae

Morales, A. G.; Perecin, Margarida Lopes Rodrigues de Aguiar; Mondin, M.
Fonte: SPRINGER; DORDRECHT Publicador: SPRINGER; DORDRECHT
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
37.04%
The genus Crotalaria is one of the largest within the family Leguminosae-Papilionoideae, with more than 600 species. However, few karyotypes have been described. In the present paper, five species belonging to the section Hedriocarpae were studied (subsection Machrostachyae), in order to better understand chromosomal evolution in Crotalaria. The results reveals that all species presented 2n = 2x = 16 with symmetrical karyotypes, and slight differences in the chromosome morphology. A secondary constriction was identified at short arm of the pair 1. The 45S rDNA was mapped in the secondary constriction and adjacent heterochromatin (NOR-heterochromatin) and a minor site was identified in C. ochroleuca. The 5S rDNA was mapped linked to 45S rDNA at chromosome 1 short arm in all species. Additional sites for 5S rDNA were identified in C. pallida, C. striata and C. mucronata. Heterochromatin blocks around the centromeres are not CMA(+) neither DAPI(+). The karyotypes of the subsection Macrostachyae are characterized by an inversion at chromosome pair one in relation to previous specialized floral species analyzed. Additional sites of 45S and 5S rDNA were assumed to be a result of transposition events by different ways. The results suggest heterochromatin differentiation and the position of ribosomal genes indicates chromosomal rearrangements during evolution. Karyotype characteristics corroborate the morphological infrageneric classification.; Coordenacao de Aperfeicoamento de Pessoal de Nivel Supeior (CAPES); Coordenacao de Aperfeicoamento de Pessoal de Nivel Supeior (CAPES); Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq); Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq); PRODOC/CAPES; PRODOC/CAPES; Fundacao de Apoio a Pesquisa do Estado de Sao Paulo (FAPESP); Fundacao de Apoio a Pesquisa do Estado de Sao Paulo (FAPESP) [Proc. 98/01170-5]

5S rDNA characterization in twelve Sciaenidae fish species (Teleostei, Perciformes): depicting gene diversity and molecular markers

Alves-Costa, Fernanda A.; Martins, Cesar; Matos, Fernanda Del Campos de; Foresti, Fausto; Oliveira, Claudio; Wasko, Adriane Pinto
Fonte: Sociedade Brasileira de Genética Publicador: Sociedade Brasileira de Genética
Tipo: Artigo de Revista Científica Formato: 303-307
ENG
Relevância na Pesquisa
37.04%
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); In order to extend the genetic data on the Sciaenidae fish family, the present study had the purpose to characterize PCR-generated 5S rDNA repeats of twelve species of this group through PAGE (Polyacrylamide Gel Electrophoresis) analysis. The results showed the occurrence of at least two different 5S rDNA size classes in all the species. Moreover, 5S rDNA repeats of one of the studied species - Isopisthus parvipinnis - were cloned and subjected to nucleotide sequencing and Southern blot membrane hybridization analyses, which permitted to confirm the existence of two major 5S rDNA classes. Phylogenetic analysis based on the nucleotide sequences of different 5S rDNA repeats of I. parvipinnis lead to their separation into two major clusters. These results may reflect the high dynamism that rules the evolution rate of 5S rDNA repeats. The obtained data suggest that 5S rDNA can be useful in genetic analyses to identify species-specific markers and determine relationships among species of the Sciaenidae group.

Two 5S rDNA arrays in Neotropical fish species: is it a general rule for fishes ?

Martins, C.; Galetti, P. M.
Fonte: Kluwer Academic Publ Publicador: Kluwer Academic Publ
Tipo: Artigo de Revista Científica Formato: 439-446
ENG
Relevância na Pesquisa
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In this paper we describe Southern blot hybridization results probed with 5S rRNA genes for several Neotropical fish species representing different taxonomic groups. All the studied species showed a general trend with the 5S rDNA tandem repeats organized in two distinct size-classes. At the same time, data on 5S rDNA organization in fish genome were summarized. Previous information on the organization and evolution of 5S rRNA gene arrays in the genome of this vertebrate group are in agreement with the Southern results here presented. Sequences obtained for several fish species have revealed the occurrence of two distinct 5S rDNA classes characterized by distinct non-transcribed spacer sequences, which are clustered in different chromosomes in some species. Moreover, the 5S rDNA loci are generally distributed in an interstitial position in the chromosomes and they are usually not syntenic to the 45S rDNA. The presence of two classes of 5S rDNA in several non-related fish species suggests that this could be a common condition for the 5S rRNA gene organization in the fish genome.

5S rDNA variation and its phylogenetic inference in the genus Leporinus (Characiformes : Anostomidae)

Ferreira, Irani A.; Oliveira, Claudio; Venere, Paulo C.; Galetti, Pedro M.; Martins, Cesar
Fonte: Springer Publicador: Springer
Tipo: Artigo de Revista Científica Formato: 253-257
ENG
Relevância na Pesquisa
36.93%
5S rDNA sequences have proven to be valuable as genetic markers to distinguish closely related species and also in the understanding of the dynamic of repetitive sequences in the genomes. In the aim to contribute to the knowledge of the evolutionary history of Leporinus (Anostomidae) and also to contribute to the understanding of the 5S rDNA sequences organization in the fish genome, analyses of 5S rDNA sequences were conducted in seven species of this genus. The 5S rRNA gene sequence was highly conserved among Leporinus species, whereas NTS exhibit high levels of variations related to insertions, deletions, microrepeats, and base substitutions. The phylogenetic analysis of the 5S rDNA sequences clustered the species into two clades that are in agreement with cytogenetic and morphological data.

Nucleotide sequence, genomic organization and chromosome localization of 5S rDNA in two species of Curimatidae (Teleostei, Characiformes)

Santos, Lessandra Viviane de Rosa; Foresti, Fausto; Wasko, Adriane Pinto; Oliveira, Claudio; Martins, Cesar
Fonte: Sociedade Brasileira de Genética Publicador: Sociedade Brasileira de Genética
Tipo: Artigo de Revista Científica Formato: 251-256
ENG
Relevância na Pesquisa
37.08%
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); The 5S ribosomal DNA (5S rDNA) of higher eukaryotes is organized in repeat units of tandem arrays composed of a 5S rDNA coding region, conserved even among non-related taxa, and a variable non-transcribed spacer sequence (NTS). To contribute to knowledge on the organization and evolution of vertebrate 5S rDNA we used PCR, nucleotide sequencing, Southern blot hybridization and chromosome fluorescence in situ hybridization (FISH) to investigate 5S rDNA tandem repeats in the South American Curimatidae fish Steindachnerina insculpta and Cyphocharax modesta. 5S rDNA repeats of 180 base pairs (bp) from both species were PCR-generated and sequenced evidencing the shortest 5S rDNA monomer so far described in eukaryote species. Southern blotting revealed that both species contained two tandem 5S rDNA classes, the PCR amplified fragment composed of 180 bp monomers and a class of 1600 bp monomers not detected by PCR. Chromosome mapping of the 5S rDNA repeats identified a major locus in both species and a second minor locus only in C. modesta. The Southern blot and chromosome mapping data indicate the presence of different types of 5S rDNA tandem repeats in the Curimatidae genome.

Molecular organization of 5S rDNA in fishes of the genus Brycon

Wasko, A. P.; Martins, C.; Wright, J. M.; Galetti, P. M.
Fonte: Natl Research Council Canada Publicador: Natl Research Council Canada
Tipo: Artigo de Revista Científica Formato: 893-902
ENG
Relevância na Pesquisa
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There are few reports on the genomic organization of 5S rDNA in fish species. To characterize the 5S rDNA nucleotide sequence and chromosomal localization in the Neotropical fishes of the genus Brycon, 5S rDNA copies from seven species were generated by PCR. The nucleotide sequences of the coding region (5S rRNA gene) and the nontranscribed spacer (NTS) were determined, revealing that the 5S rRNA genes were highly conserved, while the NTSs were widely variable among the species analyzed. Moreover, two classes of NTS were detected in each species, characterized by base substitutions and insertions-deletions. Using fluorescence in situ hybridization (FISH), two 5S rDNA chromosome loci that could be related to the two 5S rDNA NTS classes were observed in at least one of the species studied. 5S rDNA sequencing and chromosomal localization permitted the characterization of Brycon spp. and suggest a higher similarity among some of them. The data obtained indicate that the 5S rDNA can be an useful genetic marker for species identification and evolutionary studies.

Distribution of 45S and 5S rDNA sites in 23 species of Eleocharis (Cyperaceae)

Maximiano da Silva, Carlos Roberto; Quintas, Carolina Cristina; Laforga Vanzela, Andre Luis
Fonte: Springer Publicador: Springer
Tipo: Artigo de Revista Científica Formato: 951-957
ENG
Relevância na Pesquisa
37.06%
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); Studies of rDNA location in holocentric chromosomes of the Cyperaceae are scarce, but a few reports have indicated the occurrence of multiple 45S rDNA sites at terminal positions, and in the decondensed state of these regions in prometaphase/metaphase. To extend our knowledge of the number 45S and 5S rDNA sites and distribution in holocentric chromosomes of the Cyperaceae, 23 Brazilian species of Eleocharis were studied. FISH showed 45S rDNA signals always located in terminal regions, which varied from two (E. bonariensis with 2n = 20) to ten (E. flavescens with 2n = 10 and E. laeviglumis with 2n = 60). 5S rDNA showed less variation, with 16 species exhibiting two sites and 7 species four sites, preferentially at terminal positions, except for four species (E. subarticulata, E. flavescens, E. sellowiana and E. geniculata) that showed interstitial sites. The results are discussed in order to understand the predominance of terminal rDNA sites, the mechanisms involved in the interstitial positioning of 5S rDNA sites in some species, and the events of amplification and dispersion of 45S rDNA terminal sites.

Evolutionary dynamics of 5S rDNA location in acridid grasshoppers and its relationship with H3 histone gene and 45S rDNA location

Cabral-de-Mello, Diogo C.; Cabrero, Josefa; López-León, María Dolores; Camacho, Juan Pedro M.
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 921-931
ENG
Relevância na Pesquisa
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We analyze the chromosomal location of 5S rDNA clusters in 29 species of grasshoppers belonging to the family Acrididae. There was extensive variation among species for the number and location of 5S rDNA sites. Out of 148 sites detected, 75% were proximally located, 21.6% were interstitial, and only 3.4% were distal. The number of 5S rDNA sites per species varied from a single chromosome pair (in six species) to all chromosome pairs (in five species), with a range of intermediate situations. Thirteen chromosomes from eight species carried two 5S rDNA clusters. At intraspecific level, differences among populations were detected in Eyprepocnemis plorans, and some heteromorphisms have also been observed in some species. Double FISH for 5S rDNA and H3 histone gene DNA, performed on 17 of these 29 species, revealed that both markers are sometimes placed in a same chromosome but at different location, whereas they appeared to co-localize in five species (Calliptamus barbarus, Heteracris adpersa, Aiolopus strepens, Oedipoda charpentieri and O. coerulescens). Double fiber-FISH in A. strepens and O. coerulescens showed that the two DNAs are closely interspersed with variable relative amounts of both classes of DNA. Finally, no correlation was observed between the number of 5S and 45S rDNA clusters in 23 species where this information was available. These results are discussed in the light of possible mechanisms of spread that led to the extensive variation in the number of clusters observed for both rDNA types in acridid grasshoppers. © 2011 Springer Science+Business Media B.V.

Cytogenetic analysis in three Bryconamericus species (Characiformes, Characidae): first description of the 5S rDNA-bearing chromosome pairs in the genus

Piscor, Diovani; Ribacinko-Piscor, Daniela Bocagini; Fernandes, Carlos Alexandre; Parise-Maltempi, Patricia Pasquali
Fonte: Biomed Central Ltd. Publicador: Biomed Central Ltd.
Tipo: Artigo de Revista Científica Formato: 8
ENG
Relevância na Pesquisa
36.97%
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); Background: Nowadays, the genus Bryconamericus is placed in subfamily Stevardiinae within of Characidae, but not shows consistent evidence of monophyletism. The purpose of this work was to study the chromosomes of three species of Bryconamericus, aiming to add cytogenetic knowledge and contribute to the understanding of the chromosomal evolution of this genus.Results: The chromosomes of three species of Bryconamericus were analyzed using cytogenetic techniques. The karyotype of Bryconamericus stramineus contained 6 metacentric (m) + 10 submetacentric (sm) + 16 subtelocentric (st) + 20 acrocentric (a), the fundamental number (FN) of 84, one silver impregnated (Ag-NOR) pair, one pair bearing the 18S ribosomal DNA sites, another pair bearing the 5S rDNA sites, and a few positive C-bands. Bryconamericus turiuba had a karyotype containing 8 m + 10sm + 14st + 20a (FN = 84), one chromosome pair Ag-NOR, two pairs bearing the 18S rDNA sites, two pairs bearing the 5S rDNA sites, and a few C-band regions. Bryconamericus cf. iheringii had a karyotype containing 10 m + 14sm + 18st + 10a (FN = 94), including one pair with a secondary constriction Ag-NOR positive. In this karyotype the fluorescent in situ hybridization (FISH) showed the 18S and 5S rDNA probe in adjacent position.Conclusions: The results obtained in this work showed different characteristics in the organization of two multigene families...

The conservation of number and location of 18S sites indicates the relative stability of rDNA in species of Pentatomomorpha (Heteroptera)

Bardella, Vanessa Bellini; Fernandes, Thiago; Laforga Vanzela, Andre Luis
Fonte: Canadian Science Publishing, Nrc Research Press Publicador: Canadian Science Publishing, Nrc Research Press
Tipo: Artigo de Revista Científica Formato: 425-429
ENG
Relevância na Pesquisa
37.04%
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); Fluorescent in situ hybridization (FISH) with rDNA probes has been used for comparative cytogenetics studies in different groups of organisms. Although heteropterans are a large suborder within Hemiptera, studies using rDNA are limited to the infraorder Cimicomorpha, in which rDNA sites are present in the autosomes or sex chromosomes. We isolated and sequenced a conserved 18S rDNA region of Antiteuchus tripterus (Pentatomidae) and used it as a probe against chromosomes of 25 species belonging to five different families of Pentatomomorpha. The clone pAt05, with a length of 736 bp, exhibited a conserved stretch of 590 bp. FISH analysis with the probe pAt05 always demonstrated hybridization signals in sub-terminal positions, except for Euschistus heros. Apparently, there is a tendency for 18S rDNA sites to locate in autosomes, except for Leptoglossus gonagra and Euryophthalmus rufipennis, which showed signals in the m-and sex chromosomes, respectively. Although FISH has produced evidence that rearrangements are involved in rDNA repositioning, whether in different autosomes or between sex and m-chromosomes...

Genome restructuring in rye affects the expression, organization and disposition of homologous rDNA loci

Caperta, A.; Neves, Nuno; Morais-Cecílio, L.; Malhó, Rui; Viegas, Wanda
Fonte: The Company of Biologists Publicador: The Company of Biologists
Tipo: Artigo de Revista Científica
Publicado em //2002 ENG
Relevância na Pesquisa
36.97%
Research Article; The standard rye cultivar ‘Imperial’ and a structural variant carrying an intact 1R chromosome and two telocentric 1R chromosomes (short and long arms) were used to investigate expression patterns of homologous rDNA loci, and the influence of chromosome structural change on their interphase organisation and relative disposition. Sequential silver staining and in situ hybridization with the rDNA probe pTa71, established a correspondence between the expression and organization patterns of rDNA domains in metaphase and interphase cells. In most cells of the cultivar Imperial, nucleolar organizer region (NOR) silver staining on metaphase chromosomes with equivalent numbers of rDNA genes revealed a size heteromorphism between homologousrDNA loci, resulting from their differential expression. NOR heteromorphism in the structural variant line was significantly reduced. The preferential activity of one NOR over its homologue was found to be random within cells and independent of parental origin. Nucleotypic modifications mediated by changes in the 1R chromosome structure include increased proximity between homologous rDNA loci in interphase, and an increase in the frequency of cells with intra-nucleolar ribosomal condensed chromatin. These results seem to indicate a ‘sequence recognition’ process for the regulation of homologous loci.

Modulation of rye rDNA chromatin conformation induced by high temperature stress

Brazão, João Miguel Henriques da Silva
Fonte: ISA Publicador: ISA
Tipo: Relatório
Publicado em 04/01/2010 ENG
Relevância na Pesquisa
36.97%
Report - Bolsa de integração na Investigação; Epigenetic modulation has been correlated with expression patterns alterations involved in plant response to stress. However, the influence of abiotic stress, namely high temperature, in chromatin organization of plant nuclei is poorly known. The aim of this work was the analysis of rDNA chromatin organization in interphase nuclei of rye root-tip and coleoptiles from high temperature treated (HTS) and untreated plantlets, through Fluorescent In Situ Hybridization (FISH) using rDNA probes. Rye seeds were germinated in controlled conditions and HTS treated plantlets were subject to a period of 4 hours at 40oC. FISH was performed successfully using a new rDNA probe produced by PCR that can replace with advantage the pTa71 probe and the results obtained with both probes revealed significant differences in rDNA chromatin organization patterns between control and HTS in interphase nuclei from both tissues analyzed. The detected rDNA chromatin decondensation provoked by HTS may be involved in a greater potential for transcription necessary to the amendment induced by HTS and emphasize the role of chromatin epigenetic remodelling in plant adjustment pathways under stress conditions.

Nucleotide sequence, genomic organization and chromosome localization of 5S rDNA in two species of Curimatidae (Teleostei, Characiformes)

Santos,Lessandra Viviane de Rosa; Foresti,Fausto; Wasko,Adriane Pinto; Oliveira,Claudio; Martins,Cesar
Fonte: Sociedade Brasileira de Genética Publicador: Sociedade Brasileira de Genética
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2006 EN
Relevância na Pesquisa
37.08%
The 5S ribosomal DNA (5S rDNA) of higher eukaryotes is organized in repeat units of tandem arrays composed of a 5S rDNA coding region, conserved even among non-related taxa, and a variable non-transcribed spacer sequence (NTS). To contribute to knowledge on the organization and evolution of vertebrate 5S rDNA we used PCR, nucleotide sequencing, Southern blot hybridization and chromosome fluorescence in situ hybridization (FISH) to investigate 5S rDNA tandem repeats in the South American Curimatidae fish Steindachnerina insculpta and Cyphocharax modesta. 5S rDNA repeats of 180 base pairs (bp) from both species were PCR-generated and sequenced evidencing the shortest 5S rDNA monomer so far described in eukaryote species. Southern blotting revealed that both species contained two tandem 5S rDNA classes, the PCR amplified fragment composed of 180 bp monomers and a class of 1600 bp monomers not detected by PCR. Chromosome mapping of the 5S rDNA repeats identified a major locus in both species and a second minor locus only in C. modesta. The Southern blot and chromosome mapping data indicate the presence of different types of 5S rDNA tandem repeats in the Curimatidae genome.

5S rDNA characterization in twelve Sciaenidae fish species (Teleostei, Perciformes): depicting gene diversity and molecular markers

Alves-Costa,Fernanda A.; Martins,Cesar; Matos,Fernanda Del Campos de; Foresti,Fausto; Oliveira,Claudio; Wasko,Adriane P.
Fonte: Sociedade Brasileira de Genética Publicador: Sociedade Brasileira de Genética
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2008 EN
Relevância na Pesquisa
37.04%
In order to extend the genetic data on the Sciaenidae fish family, the present study had the purpose to characterize PCR-generated 5S rDNA repeats of twelve species of this group through PAGE (Polyacrylamide Gel Electrophoresis) analysis. The results showed the occurrence of at least two different 5S rDNA size classes in all the species. Moreover, 5S rDNA repeats of one of the studied species - Isopisthus parvipinnis - were cloned and subjected to nucleotide sequencing and Southern blot membrane hybridization analyses, which permitted to confirm the existence of two major 5S rDNA classes. Phylogenetic analysis based on the nucleotide sequences of different 5S rDNA repeats of I. parvipinnis lead to their separation into two major clusters. These results may reflect the high dynamism that rules the evolution rate of 5S rDNA repeats. The obtained data suggest that 5S rDNA can be useful in genetic analyses to identify species-specific markers and determine relationships among species of the Sciaenidae group.

Dynamics of the rDNA locus and its retrotransposable elements

Zhang, Xian (1977 - ); Eickbush, Thomas H.
Fonte: Universidade de Rochester Publicador: Universidade de Rochester
Tipo: Tese de Doutorado Formato: Number of Pages:xii, 218
ENG
Relevância na Pesquisa
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Thesis (Ph. D.)--University of Rochester. Dept. of Biology, 2008.; This thesis investigated the close interaction that exists between the ribosomal RNA (rRNA) gene locus, a multiple gene family organized as a tandem repeat, and the retrotransposable elements R1 and R2 which exclusively insert into the 28S rRNA genes and prevent them from making functional 28S rRNA. The dynamics of this system are subject to evolutionary forces including natural selection, recombination and retrotransposition. We have applied both empirical and theoretical approaches to investigate the effects of each of these forces.
In the first half of the thesis we scored individual R2 insertions in 16 D. simulans lines derived from one population. Several lines were identified to have high rates of retrotransposition (~0.15 new insertions /generations /locus), other lines had intermediate levels of activity and the remained lines had no activity. Lines with high R2 retrotransposition rates had greater numbers of R2 elements and a greater fraction of their rDNA units were inserted by R2. We found that R2 retrotranspositions occurred in both female and male germ lines, mostly late in germ line cell development, and was correlated with large deletions of the ribosomal RNA gene (rDNA) locus.
In the second half of the thesis...

Molecular cytogenetic analysis of the crucian carp, Carassius carassius (Linnaeus, 1758) (Teleostei, Cyprinidae), using chromosome staining and fluorescence in situ hybridisation with rDNA probes

Spoz, Aneta; Boron, Alicja; Porycka, Katarzyna; Karolewska, Monika; Ito, Daisuke; Abe, Syuiti; Kirtiklis, Lech; Juchno, Dorota
Fonte: Pensosoft Publishers Publicador: Pensosoft Publishers
Tipo: Artigo de Revista Científica
Publicado em 18/08/2014 ENG
Relevância na Pesquisa
37.01%
The crucian carp Carassius carassius (Linnaeus, 1758) is a species with restricted and decreasing distribution in Europe. Six males and six females of the species from the Baltic Sea basin in Poland were examined to show sequentially CMA3/AgNO3 staining pattern, DAPI staining, and, for the first time in literature, molecular cytogenetic analysis using double-colour fluorescence in situ hybridisation (FISH) with 28S and 5S rDNA probes. The karyotype consisted of 20 m, 36 sm and 44 sta chromosomes, NF=156. The AgNO3 stained NORs were most frequently located terminally in the short arms of two sm and two sta elements, and CMA3-positive sites were also observed suggesting abundant GC-rich repetitive DNA in the regions. Other CMA3-positive sites in the short arms of six to ten sm and sta chromosomes were detected. The results based on 28S rDNA FISH confirmed the location of rDNA sites. DAPI-negative staining of NORs suggested the scarcity of AT-rich DNA in the regions. FISH with 5S rDNA probe revealed 8-14 loci (ten and 12 in respectively 49 and 29% of metaphases). They were located in two sm and eight to ten sta chromosomes and six of them were larger than others. Simultaneously, mapping of the two rDNA families on the chromosomes of C. carassius revealed that both 28S and 5S rDNA probes were located in different chromosomes. Molecular cytogenetic data of C. carassius presented here for the first time give an important insight into the structure of chromosomes of this polyploid and declining species and may be useful in its systematics.; State Committee for Scientific Research KBN grant: (2P04C 08229)...

Heterochromatin diversity and its co-localization with 5S and 45S rDNA sites in chromosomes of four Maxillaria species (Orchidaceae)

Cabral,Juliano S.; Felix,Leonardo P.; Guerra,Marcelo
Fonte: Sociedade Brasileira de Genética Publicador: Sociedade Brasileira de Genética
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2006 EN
Relevância na Pesquisa
37.01%
We investigated four orchids of the genus Maxillaria (M. discolor, M. acicularis, M. notylioglossa and M. desvauxiana) in regard to the position of heterochromatin blocks as revealed using chromomycin A3 (CMA) and 4'-6-diamidino-2-phenylindole (DAPI) fluorochrome staining and 5S and 45S rDNA sites using fluorescence in situ hybridization (FISH). The species showed differences in chromosome number and a diversified pattern of CMA+ and DAPI+ bands, including heteromorphism for CMA+ bands. The 5S and 45S rDNA sites also varied in number and most of them were co-localized with CMA+ bands. The relationship between 5S rDNA sites and CMA+ bands was more evident in M. notylioglossa, in which the brighter CMA+ bands were associated with large 5S rDNA sites. However, not all 5S and 45S rDNA sites were co-localized with CMA+ bands, probably due to technical constraints. We compare these results to banding data from other species and suggest that not all blocks of tandemly repetitive sequences, such as 5S rDNA sites, can be observed as heterochromatin blocks.

Visualization of the ribosomal DNA (45S rDNA) of Indica rice with FISH on some phases of cell cycle and extended DNA fibers

Yun Li,Zong; Li Fu,Mei; Fang Hu,Fang; Feng Huang,Shu; Chun Song,Yun
Fonte: Biocell Publicador: Biocell
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/2006 EN
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The ribosomal DNA (45S rDNA) behaviors during the cell cycle were analyzed on interphase nuclei, prophases, metaphases, pachytene chromosomes and extended DNA fibers in rice (Oryza,sativa ssp.indica cv.Guangluai No.4) by using high-resolution fluorescent in situ hybridization (FISH). The results show that 45S rDNA is located at the ends of short arms of chromosomes 9 and 10. But the signals are much more intense on chromosome 9 than on chromosome 10 in metaphase. Pachytene chromosome has rDNA signal arrays on chromosome 9. Different phases are described and discussed. These results indicate that the activity of rDNA at individual loci may also vary through the cell cycle in rice. On extended DNA fibers, 45S rDNA signals appear as strings of numerous red spots, but some signals are missed in some regions, probably result from weak signals or intergenic spacers.