Cytogenetic Analysis of Panaqolus tankei Cramer & Sousa, 2016 (Siluriformes, Loricariidae), an Ornamental Fish Endemic to Xingu River, Brazil

2021 ◽  
pp. 1-8
Author(s):  
Alex M.V. Ferreira ◽  
Patrik F. Viana ◽  
Jansen Zuanon ◽  
Tariq Ezaz ◽  
Marcelo B. Cioffi ◽  
...  
Keyword(s):  
18S Rdna ◽  
Diploid Number ◽  
5S Rdna ◽  
Sister Group ◽  
Nucleolus Organizer ◽  
Comparative Genomic ◽  
Nucleolus Organizer Regions ◽  
Chromosomal Changes ◽  
The Impact

Despite conservation of the diploid number, a huge diversity in karyotype formulae is found in the Ancistrini tribe (Loricariidae, Hypostominae). However, the lack of cytogenetic data for many groups impairs a comprehensive understanding of the chromosomal relationships and the impact of chromosomal changes on their evolutionary history. Here, we present for the first time the karyotype of Panaqolus tankei Cramer & Sousa, 2016. We focused on the chromosomal characterization, using conventional and molecular cytogenetic techniques to unravel the evolutionary trends of this tribe. P. tankei, as most species of its sister group Pterygoplichthini, also possessess a conserved diploid number of 52 chromosomes. We observed heterochromatin regions in the centromeres of many chromosomes; pairs 5 and 6 presented interstitial heterochromatin regions, whereas pairs 23 and 24 showed extensive heterochromatin regions in their q arms. In situ localization of 18S rDNA showed hybridization signals correlating with the nucleolus organizer regions, which are located in the q arms of pair 5. However, the 5S rDNA was detected in the centromeric and terminal regions of the q arms of pair 8. (TTAGGG)n hybridized only in the terminal regions of all chromosomes. Microsatellite in situ localization showed divergent patterns, (GA)15 repeated sequences were restricted to the terminal regions of some chromosomes, whereas (AC)15 and (GT)15 showed a scattered hybridization pattern throughout the genome. Intraspecific comparative genomic hybridization was performed on the chromosomes of P. tankei to verify the existence of sex-specific regions. The results revealed only a limited number of overlapping hybridization signals, coinciding with the heterochromatin in centromeric regions without any sex-specific signals in both males and females. Our study provides a karyotype description of P. tankei, highlighting extensive differences in the karyotype formula, the heterochromatin regions, and sites of 5S and 18S rDNA, as compared with data available for the genus.

scholarly journals Karyotype variability in neotropical catfishes of the family Pimelodidae (Teleostei: Siluriformes)

2011 ◽  
Vol 9 (1) ◽  
pp. 97-105 ◽  
Author(s):  
Américo Moraes Neto ◽  
Maelin da Silva ◽  
Daniele Aparecida Matoso ◽  
Marcelo Ricardo Vicari ◽  
Mara Cristina de Almeida ◽  
...  
Keyword(s):  
Fluorescent In Situ Hybridization ◽  
Diploid Number ◽  
Molecular Cytogenetics ◽  
Ribosomal Genes ◽  
Nucleolus Organizer ◽  
Nucleolus Organizer Regions ◽  
Karyotype Variability ◽  
Interspecific Variations ◽  
The Family

Karyotypic data are presented for four species of fish belonging to the Pimelodidae family. These species show a conserved diploid number, 2n = 56 chromosomes, with different karyotypic formulae. The analyzed species showed little amount of heterochromatin located preferentially in the centromeric and telomeric regions of some chromosomes. The nucleolus organizer regions activity (Ag-NORs) and the chromosomal location of ribosomal genes by fluorescent in situ hybridization (FISH), with 18S and 5S probes, showing only one chromosome pair marked bearer of ribosomal genes, the only exception was Pimelodus britskii that presented multiple NORs and syntenic location of the 18S and 5S probes. Non-Robertsonian events, as pericentric inversion and NORs duplication are requested to explain the karyotype diversification in Pseudoplatystoma from the rio Paraguay (MS), Pimelodus from the rio Iguaçu (PR), Sorubim from the rio Paraguay (MS) and Steindachneridion from the rio Paraíba do Sul (SP). The obtained data for the karyotype macrostructure of these species corroborates a conserved pattern observed in Pimelodidae. On the other hand, interspecific variations detected by molecular cytogenetics markers made possible cytotaxonomic inferences and differentiation of the species here analyzed.

Molecular and classical chromosomal techniques reveal diversity in bushcricket genera of Barbitistini (Orthoptera)

Genome ◽  
2013 ◽  
Vol 56 (11) ◽  
pp. 667-676 ◽  
Author(s):  
E. Warchałowska-Śliwa ◽  
B. Grzywacz ◽  
A. Maryańska-Nadachowska ◽  
T.V. Karamysheva ◽  
K.-G. Heller ◽  
...  
Keyword(s):  
18S Rdna ◽  
Sex Chromosome ◽  
Nucleolus Organizer ◽  
Common Pattern ◽  
Fluorochrome Staining ◽  
Behavioral Traits ◽  
Nucleolus Organizer Regions ◽  
Ribosomal Cistron ◽  
Active Nors

The cytogenetic characteristics of 17 species of bushcricket belonging to eight genera of the tribe Barbitistini were examined by fluorescence in situ hybridization with 18S rDNA and (TTAGGn) telomeric as probes and by C-banding, silver, and fluorochrome staining. These markers were used to understand chromosomal organization and evolutionary relationships between genera or species within the same genus. The number of 18S rDNA clusters per haploid genome that co-localized with active nucleolus organizer regions (NORs) ranged from one to five, with the most common pattern being the presence of one NOR-bearing chromosome. This ribosomal cistron was preferentially located in the paracentromeric region of autosomes and very rarely in the sex chromosome. The results demonstrated coincidence between the localization of major ribosomal genes and active NORs and the position of C-band and GC-rich regions. The rDNA/NOR distribution and the composition of chromosome heterochromatin proved to be good cytogenetic markers for distinguishing species and phylogenetic lines and for understanding the genomic differentiation and evolution of Barbitistini. A comparison of cytogenetic and morphological or behavioral traits suggests that morphological and behavioral specialization in this group was not followed by major karyotype modification (except for Leptophyes). However, the occurrence and distribution of different repetitive DNA sites tends to vary among the taxa.

scholarly journals Comparative cytogenetics of Astyanax (Teleostei: Characidae) from the upper Paraguay basin

2018 ◽  
Vol 16 (1) ◽  
Author(s):  
Thais K. S. S. Teixeira ◽  
Paulo C. Venere ◽  
Daniela C. Ferreira ◽  
Sandra Mariotto ◽  
Jonathan P. Castro ◽  
...  
Keyword(s):  
Physical Mapping ◽  
18S Rdna ◽  
Diploid Number ◽  
5S Rdna ◽  
Neotropical Region ◽  
Comparative Cytogenetics ◽  
Karyotype Morphology ◽  
Taxonomic Studies

ABSTRACT Astyanax is one of the most abundant and diverse taxa of fishes in the Neotropical region. In order to increase the amount of cytogenetic information for Astyanax as well as to exhibit data to subsidize future taxonomic studies, this work analyzed three species of Astyanax: two species are cryptic, and are here reported to live in syntopy (A. abramis and A. lacustris); the first karyotype description for A. pirapuan is also presented. Cytogenetic analyzes reveal a diploid number of 2n=50 chromosomes for three species, yet with differences in their karyotype morphology. The physical mapping of 18S rDNA showed up to thirteen sites in A. pirapuan and two in A. abramis and A. lacustris. The physical mapping of 5S rDNA has proven to be an effective marker for the characterization of species of Astyanax studied in this work.

scholarly journals Ultrastructural cytochemistry of the mammalian cell nucleolus.

1990 ◽  
Vol 38 (9) ◽  
pp. 1237-1256 ◽  
Author(s):  
M Derenzini ◽  
M Thiry ◽  
G Goessens
Keyword(s):  
Structure Function ◽  
Mammalian Cell ◽  
Nucleolus Organizer ◽  
Nucleolus Organizer Regions ◽  
The Past ◽  
Nucleolar Chromatin ◽  
Function Relationship ◽  
Relationship Of ◽  
Nucleolar Components

In the present review on the organization of the mammalian cell nucleolus, we report and discuss data obtained during the past 10 years by means of cytochemical and immunocytochemical ultrastructural techniques. Particular emphasis is placed on the following topics: location of the nucleolus organizer regions in interphasic nucleolar components, structure of nucleolar chromatin in situ, and the structure-function relationship of the nucleolar components. The cytochemical and immunocytochemical results are compared and the concordant data are stressed for each topic.

FISH landmarks for barley chromosomes (Hordeum vulgare L.)

Genome ◽  
1999 ◽  
Vol 42 (2) ◽  
pp. 274-281 ◽  
Author(s):  
Susan E Brown ◽  
Janice L Stephens ◽  
Nora LV Lapitan ◽  
Dennis L Knudson
Keyword(s):  
Hordeum Vulgare ◽  
Digital Imaging ◽  
18S Rdna ◽  
Chromosomal Location ◽  
5S Rdna ◽  
Hordeum Vulgare L ◽  
Metaphase Chromosomes ◽  
Bac Clone ◽  
Rdna Probe

Barley metaphase chromosomes (2n = 14) can be identified by fluorescence in situ hybridization (FISH) and digital imaging microscopy using heterologous 18S rDNA and 5S rDNA probe sequences. When these sequences are used together, FISH landmark signals were seen so that all 7 chromosomes were uniquely identified and unambiguously oriented. The chromosomal location of the landmark signals was determined by FISH to a barley trisomic series using the 18S and 5S probes labeled with different fluorophores. The utility of these FISH landmarks for barley physical mapping was also demonstrated when an Amy-2 cDNA clone and a BAC clone were hybridized with the FISH landmark probes.Key words: Hordeum vulgare, barley, FISH, 5S, 18S, rDNA, landmarks, chromosome.

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.

scholarly journals Comparative Cytogenetics Analysis Among Peckoltia Species (Siluriformes, Loricariidae): Insights on Karyotype Evolution and Biogeography in the Amazon Region

2021 ◽  
Vol 12 ◽  
Author(s):  
Kevin Santos da Silva ◽  
Augusto Cesar Paes de Souza ◽  
Ananda Marques Pety ◽  
Renata Coelho Rodrigues Noronha ◽  
Marcelo Ricardo Vicari ◽  
...  
Keyword(s):  
Karyotype Evolution ◽  
5S Rdna ◽  
Nucleolus Organizer ◽  
Valid Species ◽  
Left Bank ◽  
Comparative Cytogenetics ◽  
Telomeric Sequences ◽  
Nucleolus Organizer Regions ◽  
Karyotype Formula ◽  
Distal Location

Peckoltia is widely distributed genus in the Amazon and Orinoco basins and the Guiana Shield, containing 18 valid species, and distinct morphotypes still needing description in the scientific literature due to its great taxonomic complexity. This study performed a comparative chromosomal analysis of two undescribed Peckoltia species (Peckoltia sp. 3 Jarumã and Peckoltia sp. 4 Caripetuba) from the Brazilian Amazon using conventional chromosome bands methods and in situ localization of the repetitive DNA (5S and 18S rRNA and U1 snRNA genes and telomeric sequences). Both species presented 2n = 52 but differed in their karyotype formula, probably due to inversions or translocations. The nucleolus organizer regions (NORs) showed distal location on a probably homeologous submetacentric pair in both species, besides an extra signal in a subtelocentric chromosome in Peckoltia sp. 4 Caripetuba. Heterochromatin occurred in large blocks, with different distributions in the species. The mapping of the 18S and 5S rDNA, and U1 snDNA showed differences in locations and number of sites. No interstitial telomeric sites were detected using the (TTAGGG)n probes. Despite 2n conservationism in Peckoltia species, the results showed variation in karyotype formulas, chromosomal bands, and locations of repetitive sites, demonstrating great chromosomal diversity. A proposal for Peckoltia karyotype evolution was inferred in this study based on the diversity of location and number of chromosomal markers analyzed. A comparative analysis with other Peckoltia karyotypes described in the literature, their biogeography patterns, and molecular phylogeny led to the hypothesis that the derived karyotype was raised in the left bank of the Amazon River.

scholarly journals Comparative analysis based on replication banding reveals the mechanism responsible for the difference in the karyotype constitution of treefrogs Ololygon and Scinax (Arboranae, Hylidae, Scinaxinae)

2017 ◽  
Vol 11 (2) ◽  
pp. 267-283 ◽  
Author(s):  
Simone Lilian Gruber ◽  
Gabriela Isabela Gomes de Oliveira ◽  
Ana Paula Zampieri Silva ◽  
Hideki Narimatsu ◽  
Célio Fernando Baptista Haddad ◽  
...  
Keyword(s):  
Chromosome Banding ◽  
Diploid Number ◽  
Nucleolus Organizer ◽  
Replication Banding ◽  
Nucleolus Organizer Regions ◽  
The Family ◽  
The Difference ◽  
Size And Morphology ◽  
Phylogenetic Revision ◽  
Dna Incorporation

According to the recent taxonomic and phylogenetic revision of the family Hylidae, species of the former Scinaxcatharinae (Boulenger, 1888) clade were included in the resurrected genus Ololygon Fitzinger, 1843, while species of the Scinaxruber (Laurenti, 1768) clade were mostly included in the genus Scinax Wagler, 1830, and two were allocated to the newly created genus JulianusDuellman et al., 2016. Although all the species of the former Scinax genus shared a diploid number of 2n = 24 and the same fundamental number of chromosome arms of FN = 48, two karyotypic constitutions were unequivocally recognized, related mainly to the distinct size and morphology of the first two chromosome pairs. Some possible mechanisms for these differences had been suggested, but without any experimental evidence. In this paper, a comparison was carried out based on replication chromosome banding, obtained after DNA incorporation of 5-bromodeoxiuridine in chromosomes of Ololygon and Scinax. The obtained results revealed that the loss of repetitive segments in chromosome pairs 1 and 2 was the mechanism responsible for karyotype difference. The distinct localization of the nucleolus organizer regions in the species of both genera also differentiates the two karyotypic constitutions.

scholarly journals Karyotypic variation in the long-whiskered catfish Pimelodus blochii Valenciennes, 1840 (Siluriformes, Pimelodidae) from the lower Tapajós, Amazonas and Trombetas Rivers

2018 ◽  
Vol 12 (3) ◽  
pp. 285-298 ◽  
Author(s):  
Ivanny Coelho da Fonseca ◽  
Luan Aércio Melo Maciel ◽  
Frank Raynner Vasconcelos Ribeiro ◽  
Luís Reginaldo Ribeiro Rodrigues
Keyword(s):  
Silver Staining ◽  
Chromosome Pair ◽  
Fluorescent In Situ Hybridization ◽  
Species Complex ◽  
Diploid Number ◽  
Acrocentric Chromosome ◽  
5S Rdna ◽  
Karyotypic Formula ◽  
Karyotypic Variation

The genus Pimelodus LaCépède, 1803 comprises 35 formally recognized species distributed along the major neotropical river basins. Despite conservatism in diploid number with 2n=56, an intense variation of chromosomal morphology (karyotypic formula) has been documented in Pimelodus species. In the present study, we analyzed karyotypes of 20 specimens, identified as Pimelodusblochii Valenciennes, 1840 and collected from the lower courses of the Tapajós, Amazonas and Trombetas Rivers. The karyotypes were characterized by Giemsa conventional staining, C-banding, silver staining (Ag-NOR) and fluorescent in situ hybridization (FISH) with 5S and 18S rDNA probes. The karyotypes showed 2n=56 chromosomes in fish from the Tapajós River. In contrast, fish from the Amazonas and Trombetas Rivers had 2n=58. The nucleolus organizing regions were labeled on the short arm of an acrocentric chromosome as demonstrated by silver staining and FISH. Signals for 18S and 5S rDNA were co-localized on one chromosome pair. Our results demonstrate karyotypic divergence between Tapajós and Amazonas-Trombetas populations of P.blochii, interpreted as supporting the existence of a species complex in this taxon.

Chromosomal Localization of 18S-28S rDNA and (TTAGGG)n Sequences in Two South African Dormice of the Genus Graphiurus (Rodentia: Gliridae)

2019 ◽  
Vol 158 (3) ◽  
pp. 145-151 ◽  
Author(s):  
Vanessa Milioto ◽  
Sara Vlah ◽  
Sofia Mazzoleni ◽  
Michail Rovatsos ◽  
Francesca Dumas
Keyword(s):  
South African ◽  
Evolutionary Dynamics ◽  
Repetitive Sequences ◽  
Nucleolus Organizer ◽  
28S Rdna ◽  
Telomeric Sequences ◽  
Nucleolus Organizer Regions ◽  
Interstitial Telomeric Sequences ◽  
Almost All

Classical cytogenetics and mapping of 18S-28S rDNA and (TTAGGG)n sequences by fluorescence in situ hybridization (FISH) was performed on Graphiurus platyops (GPL) and Graphiurus ocularis (GOC) metaphases with the aim to characterize the genomes. In both species, inverted DAPI karyotypes showed the same diploid number, 2n = 46, and hybridization of the (TTAGGG)n probe revealed interstitial telomeric sequences (ITSs) at the centromeres of almost all bi-armed chromosomes. FISH with the rDNA probe localized nucleolus organizer regions (NORs), at the terminal ends of the p arms of the subtelocentric pairs 16 and 17 in both species and detected additional signals on GPL8 and GOC18, 19, and 22. The species have similar karyotypes, but their chromosome pairs 18-22 differ in morphology; these are acrocentric in G. platyops, as also confirmed by C-banding, and subtelocentric in G. ocularis. These differences in pairs 18-22 were also highlighted by hybridization of the telomeric probe (TTAGGG)n, which showed the small p arms in G. ocularis enriched with ITSs. FISH of rDNA probes detected multiple NOR loci in G. ocularis, underlining the intense evolutionary dynamics related to these genes. Although the Graphiurus species analyzed have similar karyotypes, the results on the repetitive sequences indicate a complex pattern of genomic reorganization and evolution occurring in these phylogenetically close species.

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