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

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.

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

Cytogenetic and Genome Research ◽

10.1159/000514061 ◽

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.

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Evolutionary Relationships among Boulengerella Species (Ctenoluciidae, Characiformes): Genomic Organization of Repetitive DNAs and Highly Conserved Karyotypes

Cytogenetic and Genome Research ◽

10.1159/000480141 ◽

2017 ◽

Vol 152 (4) ◽

pp. 194-203 ◽

Cited By ~ 8

Author(s):

José F. de Souza e Sousa ◽

Patrik F. Viana ◽

Luiz A.C. Bertollo ◽

Marcelo B. Cioffi ◽

Eliana Feldberg

Keyword(s):

18S Rdna ◽

Sex Chromosome ◽

Organizer Region ◽

Nucleolus Organizer Region ◽

Nucleolus Organizer ◽

Rrna Genes ◽

Fish Family ◽

Telomeric Sequences ◽

5S Rrna Genes ◽

Species Specific

Ctenoluciidae is a Neotropical freshwater fish family whose representatives are known as bicudas. The genus Boulengerella contains 5 species, and 4 of them (B. cuvieri, B. lateristriga, B. lucius, and B. maculata) were cytogenetically analyzed in the present study by conventional and molecular procedures. All 4 species have a very similar karyotype, with 2n = 36 chromosomes (14 metacentrics + 16 submetacentrics + 6 subtelocentrics; FN = 72). However, the heterochromatin distribution pattern is species-specific. In all 4 species, the nucleolus organizer region is located in pair 18, as also confirmed by cytogenetic mapping of 18S rDNA. In turn, 5S rRNA genes are present in 2 chromosome pairs: in pair 1 of all 4 species, and in pair 10 of B. lateristriga, B. maculata, and B. cuvieri, but in pair 4 of B. lucius. The telomeric probe highlighted terminal regions in all chromosomes, as well as an interstitial centromeric sequence in pair 3 of the 3 first-mentioned species. Notably, a conspicuous heteromorphic secondary constriction in chromosomes 18 was found only in the males of the 3 species, rendering one of the homologs much larger than the other one. This feature, associated with a large 18S rDNA block and accumulation of telomeric sequences, suggests the presence of an XX/XY sex chromosome system in the analyzed Boulengerella species.

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Ultrastructural cytochemistry of the mammalian cell nucleolus.

Journal of Histochemistry & Cytochemistry ◽

10.1177/38.9.2201735 ◽

1990 ◽

Vol 38 (9) ◽

pp. 1237-1256 ◽

Cited By ~ 72

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.

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Genetic and cytogenetic analyses of the A genome of Triticum monococcum. VI. Production and identification of primary trisomics using the C-banding technique

Genome ◽

10.1139/g90-081 ◽

1990 ◽

Vol 33 (4) ◽

pp. 542-555 ◽

Cited By ~ 23

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.

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

Cytogenetic and Genome Research ◽

10.1159/000500985 ◽

2019 ◽

Vol 158 (3) ◽

pp. 145-151 ◽

Cited By ~ 4

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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Heterochromatin characterization and ribosomal gene location in two monotypic genera of bloodsucker bugs (Cimicidae, Heteroptera) with holokinetic chromosomes and achiasmatic male meiosis

Bulletin of Entomological Research ◽

10.1017/s0007485314000650 ◽

2014 ◽

Vol 104 (6) ◽

pp. 788-793 ◽

Cited By ~ 6

Author(s):

M.G. Poggio ◽

O. Di Iorio ◽

P. Turienzo ◽

A. G. Papeschi ◽

M.J. Bressa

Keyword(s):

Central Region ◽

Sex Chromosome ◽

Male Meiosis ◽

Ribosomal Gene ◽

Nucleolus Organizer ◽

Gene Location ◽

Holokinetic Chromosomes ◽

Small Areas ◽

Nucleolus Organizer Regions ◽

Autosomal Pair

AbstractMembers of the family Cimicidae (Heteroptera: Cimicomorpha) are temporary bloodsuckers on birds and bats as primary hosts and humans as secondary hosts.Acanthocrios furnarii(2n=12=10+XY, male) andPsitticimex uritui(2n=31=28+X1X2Y, male) are two monotypic genera of the subfamily Haematosiphoninae, which have achiasmatic male meiosis of collochore type. Here, we examined chromatin organization and constitution of cimicid holokinetic chromosomes by determining the amount, composition and distribution of constitutive heterochromatin, and number and location of nucleolus organizer regions (NORs) in both species. Results showed that these two bloodsucker bugs possess high heterochromatin content and have an achiasmatic male meiosis, in which three regions can be differentiated in each autosomal bivalent: (i) terminal heterochromatic regions in repulsion; (ii) a central region, where the homologous chromosomes are located parallel but without contact between them; and (iii) small areas within the central region, where collochores are detected.Acanthocrios furnariipresented a single NOR on an autosomal pair, whereasP. urituipresented two NORs, one on an autosomal pair and the other on a sex chromosome. All NORs were found to be associated with CMA3bright bands, indicating that the whole rDNA repeating unit is rich in G+C base pairs. Based on the variations in the diploid autosomal number, the presence of simple and multiple sex chromosome systems, and the number and location of 18S rDNA loci in the two Cimicidae species studied, we might infer that rDNA clusters and genome are highly dynamic among the representatives of this family.

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Karyotyping Melandrium album, a dioecious plant with heteromorphic sex chromosomes

Genome ◽

10.1139/g90-082 ◽

1990 ◽

Vol 33 (4) ◽

pp. 556-562 ◽

Cited By ~ 28

Author(s):

D. D. Ciupercescu ◽

J. Veuskens ◽

A. Mouras ◽

D. Ye ◽

M. Briquet ◽

...

Keyword(s):

In Situ Hybridization ◽

Sex Chromosomes ◽

Nucleolus Organizer ◽

Rrna Genes ◽

Hybridization Technique ◽

Metaphase Chromosomes ◽

Nucleolus Organizer Regions ◽

Melandrium Album ◽

Group B

Mitotic metaphase chromosomes of Melandrium album obtained from root protoplasts were studied. Morphologically, the chromosomes were either metacentrics or submetacentrics. They were classified into three distinct groups: group A comprising six pairs of autosomal metacentrics, group B comprising five pairs of autosomal submetacentrics, and the sex chromosomes: X and Y. The X chromosome is a metacentric (r = 1.44), which accounts for more than 14% of the genome. The Y chromosome is a metacentric with, virtually, equal arms (r = 1.09) and accounts for 21% of the genome, being the largest of the complement. The Y:X ratio was 1.4. Ethidium bromide, caffeine, and vinblastine were used to obtain a better resolution and higher frequency of satellited chromosomes 7q and 9p. The proposed karyotype of M. album is 2n = 24, XX, s(7q;9p) for female and 2n = 24, XY, s(7q;9p) for male plants. Nucleolus organizer regions (NORs) were present at the telomeric sites of three chromosome pairs: 7q, 9p, and 10p. The NORs were polymorphic, particularly between the nonhomologous chromosomes. The in situ hybridization technique localized the rRNA genes on four chromosome pairs: 5p, 7q, 9p, and 10p. The discrepancy between the NORs and the hybridization signals was probably due to the fact that NORs were restricted only to transcriptionally active rRNA genes. It was concluded that for a complete description and characterization of rRNA genes, both NOR detection and in situ hybridization techniques, as complementary methods, should be employed.Key words: Melandrium album, karyotype, satellites, idiogram, nucleolus organizer regions, in situ hybridization.

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Karyotype description and evidence of multiple sex chromosome system X1X1X2X2/X1X2Y in Potamotrygon aff. motoro and P. falkneri (Chondrichthyes: Potamotrygonidae) in the upper Paraná River basin, Brazil

Neotropical Ichthyology ◽

10.1590/s1679-62252011000100020 ◽

2011 ◽

Vol 9 (1) ◽

pp. 201-208 ◽

Cited By ~ 8

Author(s):

Vanessa Paes da Cruz ◽

Cristiane Kioko Shimabukuro-Dias ◽

Claudio Oliveira ◽

Fausto Foresti

Keyword(s):

Sex Chromosome ◽

Chromosomal Rearrangements ◽

Chromosomal Evolution ◽

Nucleolus Organizer ◽

Banding Technique ◽

Nucleolus Organizer Regions ◽

Sex Chromosome System ◽

Upper Paraná River ◽

Upper Paraná River Basin ◽

Almost All

Cytogenetic analysis of Potamotrygon aff. motoro and P. falkneri indicated the occurrence of an X1X1X2X2/X1X2 Y multiple sex chromosome system in both species, with 2n = 66 chromosomes for females and 2n = 65 chromosomes for males. The nucleolus organizer regions (NORs) identified using Ag-NOR technique showed that both species have multiple Ag-NORs (5 to 7 chromosomes stained). C-banding technique indicated the presence of heterochromatic blocks in the centromeric regions of almost all chromosomes in both species. Through this study there was evidence of heterogeneity in the karyotypes, which suggests that chromosomal rearrangements such as inversions and/or translocations occurred during the chromosomal evolution in two species of this genus.

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Chromosome Dynamics Regulating Genomic Dispersion and Alteration of Nucleolus Organizer Regions (NORs)

Cells ◽

10.3390/cells9040971 ◽

2020 ◽

Vol 9 (4) ◽

pp. 971

Author(s):

Hirohisa Hirai

Keyword(s):

Transcriptional Activity ◽

Nucleolus Organizer ◽

Nucleolus Organizer Regions ◽

Dispersion Systems ◽

Rdna Loci ◽

Silver Nitrate Staining ◽

Staining Methods ◽

Acrocentric Chromosomes ◽

Reciprocal Associations

The nucleolus organizer regions (NORs) demonstrate differences in genomic dispersion and transcriptional activity among all organisms. I postulate that such differences stem from distinct genomic structures and their interactions from chromosome observations using fluorescence in situ hybridization and silver nitrate staining methods. Examples in primates and Australian bulldog ants indicate that chromosomal features indeed play a significant role in determining the properties of NORs. In primates, rDNA arrays that are located on the short arm of acrocentrics frequently form reciprocal associations (“affinity”), but they lack such associations (“non-affinity”) with other repeat arrays—a binary molecular effect. These “rules” of affinity vs. non-affinity are extrapolated from the chromosomal configurations of meiotic prophase. In bulldog ants, genomic dispersions of rDNA loci expand much more widely following an increase in the number of acrocentric chromosomes formed by centric fission. Affinity appears to be a significantly greater force: associations likely form among rDNA and heterochromatin arrays of acrocentrics—thus, more acrocentrics bring about more rDNA loci. The specific interactions among NOR-related genome structures remain unclear and require further investigation. Here, I propose that there are limited and non-limited genomic dispersion systems that result from genomic affinity rules, inducing specific chromosomal configurations that are related to NORs.

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

Neotropical Ichthyology ◽

10.1590/s1679-62252011005000002 ◽

2011 ◽

Vol 9 (1) ◽

pp. 97-105 ◽

Cited By ~ 15

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.

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