Chromosomal Mapping of Repeat DNA in Bergiaria westermanni (Pimelodidae, Siluriformes): Localization of 45S rDNA in B Chromosomes

2018 ◽  
Vol 154 (2) ◽  
pp. 99-106 ◽  
Author(s):  
Geovana C. Malimpensa ◽  
Josiane B. Traldi ◽  
Danyelle Toyama ◽  
Flávio Henrique-Silva ◽  
Marcelo R. Vicari ◽  
...  
Keyword(s):  
Chromosomal Rearrangements ◽  
Indirect Evidence ◽  
5S Rdna ◽  
B Chromosomes ◽  
Chromosomal Mapping ◽  
Interindividual Variation ◽  
Rrna Genes ◽  
45S Rdna ◽  
Rdna Sites ◽  
Repeat Dna

The occurrence of repetitive DNA in autosomes and B chromosomes of Bergiaria westermanni was examined using conventional and molecular cytogenetic techniques. This species exhibited 2n = 56 chromosomes, with intra- and interindividual variation in the number of heterochromatic B chromosomes (from 0 to 4). The 5S rDNA was localized in pairs 1 and 5, and histone probes (H1, H3, and H4) and U2 small nuclear RNA were syntenic with 5S rDNA in pair 5. Histone sequences were also located in chromosome pair 14. The (GATA)n sequence was dispersed throughout the autosomes and B chromosomes, with clusters (microsatellite accumulation) in some chromosome regions. The telomeric probe revealed no signs of chromosomal rearrangements in the genome of B. westermanni. The 45S rDNA sites were detected in the terminal region of pair 27; these sites corresponded to a GC-rich heterochromatin block. In addition, 3 of the 4 B chromosomes also contained 45S rDNA copies. Silver nitrate staining in interphase nuclei provided indirect evidence of the expression of these rRNA genes in B chromosomes, indicating the probable origin of these elements. This report shows plasticity in the chromosomal localization of repeat DNA in B. westermanni and features a discussion of genomic diversification.

scholarly journals Analyses of the Updated “Animal rDNA Loci Database” with an Emphasis on Its New Features

2021 ◽  
Vol 22 (21) ◽  
pp. 11403
Author(s):  
Jana Sochorová ◽  
Francisco Gálvez ◽  
Roman Matyášek ◽  
Sònia Garcia ◽  
Aleš Kovařík
Keyword(s):  
Sex Chromosomes ◽  
5S Rdna ◽  
High Variability ◽  
Rrna Genes ◽  
45S Rdna ◽  
Data Analyses ◽  
Rdna Sites ◽  
Rdna Loci ◽  
Staining Methods ◽  
Active Nors

We report on a major update to the animal rDNA loci database, which now contains cytogenetic information for 45S and 5S rDNA loci in more than 2600 and 1000 species, respectively. The data analyses show the following: (i) A high variability in 5S and 45S loci numbers, with both showing 50-fold or higher variability. However, karyotypes with an extremely high number of loci were rare, and medians generally converged to two 5S sites and two 45S rDNA sites per diploid genome. No relationship was observed between the number of 5S and 45S loci. (ii) The position of 45S rDNA on sex chromosomes was relatively frequent in some groups, particularly in arthropods (14% of karyotypes). Furthermore, 45S rDNA was almost exclusively located in microchromosomes when these were present (in birds and reptiles). (iii) The proportion of active NORs (positively stained with silver staining methods) progressively decreased with an increasing number of 45S rDNA loci, and karyotypes with more than 12 loci showed, on average, less than 40% of active loci. In conclusion, the updated version of the database provides some new insights into the organization of rRNA genes in chromosomes. We expect that its updated content will be useful for taxonomists, comparative cytogeneticists, and evolutionary biologists. 

scholarly journals Ribosomal DNA localization on Lathyrus species chromosomes by FISH

2020 ◽  
Vol 18 (1) ◽  
Author(s):  
Hoda B. M. Ali ◽  
Samira A. Osman
Keyword(s):  
Genome Mapping ◽  
Chromosome Complement ◽  
5S Rdna ◽  
Rdna Locus ◽  
5S Rrna ◽  
Rrna Genes ◽  
45S Rdna ◽  
Metaphase Chromosomes ◽  
Lathyrus Odoratus ◽  
5S Rrna Genes

Abstract Background Fluorescence In Situ Hybridization (FISH) played an essential role to locate the ribosomal RNA genes on the chromosomes that offered a new tool to study the chromosome structure and evolution in plant. The 45S and 5S rRNA genes are independent and localized at one or more loci per the chromosome complement, their positions along chromosomes offer useful markers for chromosome discriminations. In the current study FISH has been performed to locate 45S and 5S rRNA genes on the chromosomes of nine Lathyrus species belong to five different sections, all have chromosome number 2n=14, Lathyrus gorgoni Parl, Lathyrus hirsutus L., Lathyrus amphicarpos L., Lathyrus odoratus L., Lathyrus sphaericus Retz, Lathyrus incospicuus L, Lathyrus paranensis Burkart, Lathyrus nissolia L., and Lathyrus articulates L. Results The revealed loci of 45S and 5S rDNA by FISH on metaphase chromosomes of the examined species were as follow: all of the studied species have one 45S rDNA locus and one 5S rDNA locus except L. odoratus L., L. amphicarpos L. and L. sphaericus Retz L. have two loci of 5S rDNA. Three out of the nine examined species have the loci of 45S and 5S rRNA genes on the opposite arms of the same chromosome (L. nissolia L., L. amphicarpos L., and L. incospicuus L.), while L. hirsutus L. has both loci on the same chromosome arm. The other five species showed the loci of the two types of rDNA on different chromosomes. Conclusion The detected 5S and 45S rDNA loci in Lathyrus could be used as chromosomal markers to discriminate the chromosome pairs of the examined species. FISH could discriminate only one chromosome pair out of the seven pairs in three species, in L. hirsutus L., L. nissolia L. and L. incospicuus L., and two chromosome pairs in five species, in L. paranensis Burkart, L. odoratus L., L. amphicarpos L., L. gorgoni Parl. and L. articulatus L., while it could discriminate three chromosome pairs in L. sphaericus Retz. these results could contribute into the physical genome mapping of Lathyrus species and the evolution of rDNA patterns by FISH in the coming studies in future.

Effects of the diploidisation process upon the 5S and 35S rDNA sequences in the allopolyploid species of the Dilatata group of Paspalum (Poaceae, Paniceae)

2019 ◽  
Vol 67 (7) ◽  
pp. 521
Author(s):  
Magdalena Vaio ◽  
Cristina Mazzella ◽  
Marcelo Guerra ◽  
Pablo Speranza
Keyword(s):  
Evolutionary Dynamics ◽  
In Situ Hybridisation ◽  
5S Rdna ◽  
Its Region ◽  
Variable Number ◽  
Rrna Genes ◽  
Fluorescence In Situ Hybridisation ◽  
Rdna Sites ◽  
35S Rdna ◽  
Genome Restructuring

The Dilatata group of Paspalum includes species and biotypes native to temperate South America. Among them, five sexual allotetraploids (x = 10) share the same IIJJ genome formula: P. urvillei Steud, P. dasypleurum Kunze ex Desv., P. dilatatum subsp. flavescens Roseng., B.R. Arrill. & Izag., and two biotypes P. dilatatum Vacaria and P. dilatatum Virasoro. Previous studies suggested P. intermedium Munro ex Morong & Britton and P. juergensii Hack. or related species as their putative progenitors and donors of the I and J genome, respectively, and pointed to a narrow genetic base for their maternal origin. It has not yet been established whether the various members of the Dilatata group are the result of a single or of multiple allopolyploid formations. Here, we aimed to study the evolutionary dynamics of rRNA genes after allopolyploidisation in the Dilatata group of Paspalum and shed some light into the genome restructuring of the tetraploid taxa with the same genome formula. We used double target fluorescence in situ hybridisation of 35S and 5S rDNA probes and sequenced the nrDNA internal transcribed spacer (ITS) region. A variable number of loci at the chromosome ends were observed for the 35S rDNA, from 2 to 6, suggesting gain and loss of sites. For the 5S rDNA, only one centromeric pair of signals was observed, indicating a remarkable loss after polyploidisation. All ITS sequences generated were near identical to the one found for P. intermedium. Although sequences showed a directional homogeneisation towards the putative paternal progenitor in all tetraploid species, the observed differences in the number and loss of rDNA sites suggest independent ongoing diploidisation processes in all taxa and genome restructuring following polyploidy.

Comparative chromosomal localization of 45S and 5S rDNAs and implications for genome evolution in Cucumis

Genome ◽  
2016 ◽  
Vol 59 (7) ◽  
pp. 449-457 ◽  
Author(s):  
Zhen-Tao Zhang ◽  
Shu-Qiong Yang ◽  
Zi-Ang Li ◽  
Yun-Xia Zhang ◽  
Yun-Zhu Wang ◽  
...  
Keyword(s):  
Chromosomal Localization ◽  
5S Rdna ◽  
Chromosome Analysis ◽  
45S Rdna ◽  
Evolutionary Patterns ◽  
Site Number ◽  
Rdna Sites ◽  
Wild Accessions ◽  
Ribosomal Dnas

Ribosomal DNAs are useful cytogenetic markers for chromosome analysis. Studies investigating site numbers and distributions of rDNAs have provided important information for elucidating genome organization and chromosomal relationships of many species by fluorescence in situ hybridization. But relevant studies are scarce for species of the genus Cucumis, especially in wild species. In the present study, FISH was conducted to investigate the organization of 45S and 5S rDNA among 20 Cucumis accessions, including cultivars and wild accessions. Our results showed that the number of 45S rDNA sites varied from one to five pairs in different accessions, and most of these sites are located at the terminal regions of chromosomes. Interestingly, up to five pairs of 45S rDNA sites were observed in C. sativus var. sativus, the species which has the lowest chromosome number, i.e., 2n = 14. Only one pair of 5S rDNA sites was detected in all accessions, except for C. heptadactylus, C. sp, and C. spp that had two pairs of 5S rDNA sites. The distributions of 5S rDNA sites showed more variation than 45S rDNA sites. The phylogenetic analysis in this study showed that 45S and 5S rDNA have contrasting evolutionary patterns. We find that 5S rDNA has a polyploidization-related tendency towards the terminal location from an interstitial location but maintains a conserved site number, whereas the 45S rDNA showed a trend of increasing site number but a relatively conserved location.

scholarly journals Transcription of genomic bovine and Xenopus laevis DNA species by RNA polymerase III in HeLa-cell cytosol extracts

1986 ◽  
Vol 237 (3) ◽  
pp. 827-835 ◽  
Author(s):  
J J Furth ◽  
C Y Su
Keyword(s):  
Xenopus Laevis ◽  
Rna Polymerase ◽  
Hela Cell ◽  
Rna Polymerase Iii ◽  
5S Rdna ◽  
5S Rrna ◽  
Rrna Genes ◽  
Polymerase Iii ◽  
Repeat Dna ◽  
Cell Cytosol

RNA transcribed from genomic Xenopus laevis DNA by RNA polymerase III in HeLa-cell extract was found in discrete size classes and was transcribed from at least two different Xenopus repeat DNA species. Very little 5S ribosomal RNA was transcribed, contrasting with results obtained on transcription of genomic Xenopus DNA by Xenopus extract [Bogenhagen et al. (1982) Cell 28, 413-421]. The low transcription was not due to an inability to use 5S rDNA templates, since the cloned Xenopus 5S ribosomal gene and pseudogene were effective templates for RNA polymerase III in HeLa extract. RNA transcribed from genomic bovine DNA by RNA polymerase III in HeLa-cell cytosol extract consisted of 120-nucleotide RNA and a larger amount of heterogeneously sized RNA (180-650 nucleotides). Only a small portion of the 120-nucleotide RNA was 5S rRNA. Most of the 120-nucleotide RNA and the larger RNA species were transcribed from one bovine repeat DNA. Genes for 5S rRNA and bovine repeat DNA were transcribed roughly in proportion to their frequency in Bos, contrasting with results in a homologous system in which transcription of repeat genes is repressed [Furth (1985) Biochem. Biophys. Res. Commun. 131, 551-556]. Bovine 5S rRNA genes appear to be concentrated on one DNA fragment obtained by restriction-enzyme-HindIII digestion of genomic bovine DNA.

scholarly journals Genome Mutation Revealed by Artificial Hybridization between Chrysanthemum yoshinaganthum and Chrysanthemum vestitum Assessed by FISH and GISH

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Magdy Hussein Abd El-Twab ◽  
Katsuhiko Kondo
Keyword(s):  
5S Rdna ◽  
45S Rdna ◽  
Multicolor Fish ◽  
Hybrid Plants ◽  
Artificial Hybrid ◽  
Yellow Color ◽  
Rdna Sites ◽  
Labeled Probe

Present study has been done to investigate artificial interspecific crossability between Japanese Chrysanthemum yoshinaganthum (2n=36) and Chinese C. vestitum (2n=54), which were cultured in vitro and in vivo and characterization of their artificial hybrid chromosomes and type of changes assessed by FISH and GISH. GISH was applied by using biotin-labeled total genomic DNA probe of C. vestitum, which were mixed with blocking DNA of C. yoshinaganthum. Approximately 18 yellow-green colored chromosomes of C. vestitum were detected by the probe, approximately 18 yellow-red- mixed colored chromosomes could be common chromosomes of the two species, and nine chromosomes were relatively red of Ch. yoshinaganthum that were not detected by the probe. The expected average of FISH six signals of 5S rDNA sites and ten of 45S rDNA were observed on the chromosomes of three and six hybrid plants, respectively. Multicolor FISH signals showed unexpected average of seven and 14 yellow signals of 5S rDNA sites on seven and thirteen chromosomes simultaneous with ten and 11 red signals of 45S rDNA sites on ten and 11 chromosomes which were detected by the probes respectively. FISH mapping of the 5S rDNA at terminal sites was detected in hybrid chromosomes, for the first time. Yellow-color signals of the telomeres were detected by the biotin-labeled probe of the PCR-amplified telomeric probe in interphase and terminal sites in metaphase. All chromosomes that showed terminal signals except four chromosomes showed subterminal sites of telomeres indicating the presence of translocations.

scholarly journals Genomic Organization of Repetitive DNA Elements and Extensive Karyotype Diversity of Silurid Catfishes (Teleostei: Siluriformes): A Comparative Cytogenetic Approach

2019 ◽  
Vol 20 (14) ◽  
pp. 3545
Author(s):  
Sukhonthip Ditcharoen ◽  
Luiz Antonio Carlos Bertollo ◽  
Petr Ráb ◽  
Eva Hnátková ◽  
Wagner Franco Molina ◽  
...  
Keyword(s):  
Evolutionary Dynamics ◽  
Chromosomal Rearrangements ◽  
5S Rdna ◽  
Comparative Genomic ◽  
Molecular Cytogenetic ◽  
Rdna Sites ◽  
Genomic Divergence ◽  
Fish Chromosomes ◽  
Dna Elements ◽  
Repetitive Dna Elements

The catfish family Siluridae contains 107 described species distributed in Asia, but with some distributed in Europe. In this study, karyotypes and other chromosomal characteristics of 15 species from eight genera were examined using conventional and molecular cytogenetic protocols. Our results showed the diploid number (2n) to be highly divergent among species, ranging from 2n = 40 to 92, with the modal frequency comprising 56 to 64 chromosomes. Accordingly, the ratio of uni- and bi-armed chromosomes is also highly variable, thus suggesting extensive chromosomal rearrangements. Only one chromosome pair bearing major rDNA sites occurs in most species, except for Wallago micropogon, Ompok siluroides, and Kryptoterus giminus with two; and Silurichthys phaiosoma with five such pairs. In contrast, chromosomes bearing 5S rDNA sites range from one to as high as nine pairs among the species. Comparative genomic hybridization (CGH) experiments evidenced large genomic divergence, even between congeneric species. As a whole, we conclude that karyotype features and chromosomal diversity of the silurid catfishes are unusually extensive, but parallel some other catfish lineages and primary freshwater fish groups, thus making silurids an important model for investigating the evolutionary dynamics of fish chromosomes.

scholarly journals Karyotype differentiation and cytotaxonomic considerations in species of Serrasalmidae (Characiformes) from the Amazon basin

2012 ◽  
Vol 10 (1) ◽  
pp. 53-58 ◽  
Author(s):  
Celeste Mutuko Nakayama ◽  
Eliana Feldberg ◽  
Luiz Antonio Carlos Bertollo
Keyword(s):  
Amazon Basin ◽  
5S Rdna ◽  
Rrna Genes ◽  
Rdna Sites ◽  
Chromosomal Pair ◽  
Pair Number ◽  
5S Rrna Genes ◽  
Probable Occurrence ◽  
Acrocentric Chromosomes ◽  
Karyotype Differentiation

Six species of Serrasalmidae from the central Amazon, representatives of the genera Serrasalmus (S. elongatus, S. maculatus, S. cf. rhombeus, and S. rhombeus), Pygocentrus (P. nattereri), and Colossoma (C. macropomum), were analyzed regarding the distribution of the Ag-NORs, C-positive heterochromatin and 18S and 5S rRNA genes on the chromosomes. All specimens had 2n = 60 chromosomes, except S. cf. rhombeus, with 2n = 58, and C. macropomum with 2n = 54 chromosomes. The Ag-NORs were multiple and located on the short arms of subtelo-acrocentric chromosomes in all Serrasalmus species and in P. nattereri, but were found on metacentric chromosomes in C. macropomum. The 18S rDNA sites were usually coincident with Ag-NORs, although some species had a higher number and/or a distinct localization of these sites. C-positive heterochromatin was preferentially situated in centromeric regions, remarkably on metacentric pair number 7 in all Serrasalmus species and number 3 in P. nattereri, which beared a conspicuous proximal C-band on the long arms. The 5S rDNA sites were detected in a single chromosomal pair in all species. In Serrasalmus and P. nattereri, this pair was the number 7 and 3, respectively, thereby revealing its co-localization with the conspicuous heterochromatic band. However, in C. macropomum, only one homologue (probably belonging to pair number 12) exhibited 5S rDNA sites on the short arms, close to the centromere. The present data revealed reliable cytotaxonomic markers, enabling the evaluation of karyotype differentiation and interrelationships among Serrasalmidae, as well as the probable occurrence of a species complex in S. rhombeus.

scholarly journals Comparative cytogenetic analyses in Ancistrus species (Siluriformes: Loricariidae)

2020 ◽  
Vol 18 (2) ◽  
Author(s):  
Larissa Glugoski ◽  
Geize Deon ◽  
Stephane Schott ◽  
Marcelo R. Vicari ◽  
Viviane Nogaroto ◽  
...  
Keyword(s):  
Chromosomal Rearrangements ◽  
5S Rdna ◽  
Chromosomal Evolution ◽  
Sister Group ◽  
Fusion Event ◽  
Rdna Cluster ◽  
Strand Breaks ◽  
Rdna Sites ◽  
Cytogenetic Analyses ◽  
Ribosomal Dnas

ABSTRACT Ancistrus is a specious genus of armored catfishes that has been extensively used for cytogenetic studies in the last 17 years. A comparison of the extensive karyotypic plasticity within this genus is presented with new cytogenetic analysis for Ancistrus cf. multispinis and Ancistrus aguaboensis. This study aims to improve our understanding of chromosomal evolution associated with changes in the diploid number (2n) and the dispersion of ribosomal DNAs (rDNAs) within Ancistrus. Ancistrus cf. multispinis and A. aguaboensis exhibit 2n of 52 and 50 chromosomes, respectively. Given that A. cf. multispinis shares a 2n = 52 also found in Pterygoplichthyini, the sister group for Ancistrini, a Robertsonian (Rb) fusion event is proposed for the 2n reduction in A. aguaboensis. 5S rDNAs pseudogenes sites have already been associated with Rb fusion in Ancistrus and our analysis suggests that the 2n reduction in A. aguaboensis was triggered by double strand breaks (DSBs) and chromosomal rearrangements at 5S rDNA sites. The presence of evolutionary breakpoint regions (EBRs) into rDNA cluster is proposed to explain part of the Rb fusion in Ancistrus. Cytogenetic data presented extends the diversity already documented in Ancistrus to further understand the role of chromosomal rearrangements in the diversification of Ancistrini.

Chromosomal mapping of 18S–28S and 5S rRNA genes by two-colour fluorescent in situ hybridization in six sturgeon species

Genome ◽  
2003 ◽  
Vol 46 (3) ◽  
pp. 473-477 ◽  
Author(s):  
Francesco Fontana ◽  
Massimo Lanfredi ◽  
Leonardo Congiu ◽  
Marilena Leis ◽  
Milvia Chicca ◽  
...  
Keyword(s):  
In Situ Hybridization ◽  
Close Association ◽  
5S Rdna ◽  
28S Rdna ◽  
5S Rrna ◽  
Chromosomal Mapping ◽  
Rrna Genes ◽  
Acipenser Baerii ◽  
Sturgeon Species

The number and distribution of the 18S–28S and 5S rRNA (rDNA) gene sequences were examined on mitotic chromosomes of six sturgeon species by two-colour in situ hybridization. Four of the six species, Huso huso, Acipenser stellatus, Acipenser sturio, and Acipenser ruthenus, with about 120 chromosomes, showed from six to eight 18S–28S rDNA signals, while 5S rDNA signals were on only one chromosome pair. The two species with 250–270 chromosomes, Acipenser baerii and Acipenser transmontanus, showed from 10 to 12 18S–28S sites and two chromosome pairs bearing 5S rDNA signals. In all examined species, the rather intense 5S rDNA signals apparently overlapped those of 18S–28S rDNA. These data support the diploid–tetraploid relationships between the two chromosome groups of sturgeons. The close association between the two rDNA families in species belonging to an ancestral fish order, such as Acipenseriformes, supports the hypothesis that the association represents a primitive condition.Key words: Acipenseriformes, FISH, fish cytogenetics, ribosomal genes.

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