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.

scholarly journals Interspecific cytogenetic relationships in three Acestrohynchus species (Acestrohynchinae, Characiformes) reveal the existence of possible cryptic species

2020 ◽  
Vol 14 (1) ◽  
pp. 27-42
Author(s):  
Alber Sousa Campos ◽  
Ramon Marin Favarato ◽  
Eliana Feldberg
Keyword(s):  
Chromosome Pair ◽  
Organizer Region ◽  
Nucleolus Organizer Region ◽  
5S Rdna ◽  
Nucleolus Organizer ◽  
Telomeric Sequences ◽  
Interstitial Telomeric Sequences ◽  
Rdna Sites ◽  
Species Specific

The karyotypes and chromosomal characteristics of three Acestrorhynchus Eigenmann et Kennedy, 1903 species were examined using conventional and molecular protocols. These species had invariably a diploid chromosome number 2n = 50. Acestrorhynchus falcatus (Block, 1794) and Acestrorhynchus falcirostris (Cuvier, 1819) had the karyotype composed of 16 metacentric (m) + 28 submetacentric (sm) + 6 subtelocentric (st) chromosomes while Acestrorhynchus microlepis (Schomburgk, 1841) had the karyotype composed of 14m+30sm+6st elements. In this species, differences of the conventional and molecular markers between the populations of Catalão Lake (AM) and of Apeu Stream (PA) were found. Thus the individuals of Pará (Apeu) were named Acestrorhynchus prope microlepis. The distribution of the constitutive heterochromatin blocks was species-specific, with C-positive bands in the centromeric and telomeric regions of a number of different chromosomes, as well as in interstitial sites and completely heterochromatic arms. The phenotypes of nucleolus organizer region (NOR) were simple, i. e. in a terminal position on the p arm of pair No. 23 except in A. microlepis, in which it was located on the q arm. Fluorescence in situ hybridization (FISH) revealed 18S rDNA sites on one chromosome pair in karyotype of A. falcirostris and A. prope microlepis (pair No. 23) and three pairs (Nos. 12, 23, 24) in A. falcatus and (Nos. 8, 23, 24) in A. microlepis; 5S rDNA sites were detected in one chromosome pair in all three species. The mapping of the telomeric sequences revealed terminal sequences in all the chromosomes, as well as the presence of interstitial telomeric sequences (ITSs) in a number of chromosome pairs. The cytogenetic data recorded in the present study indicate that A. prope microlepis may be an unnamed species.

The Relationship between the (In-)Stability of NORs and Their Chromosomal Location: The Example of Cercopithecidae and a Short Review of Other Primates

2017 ◽  
Vol 153 (3) ◽  
pp. 138-146 ◽  
Author(s):  
Michèle Gerbault-Seureau ◽  
Lauriane Cacheux ◽  
Bernard Dutrillaux
Keyword(s):  
Chromosome Evolution ◽  
Short Review ◽  
Nucleolus Organizer ◽  
Fragile Sites ◽  
Metaphase Chromosomes ◽  
Nucleolus Organizer Regions ◽  
Size Number ◽  
Almost All ◽  
The Relationship

Amongst Cercopithecidae, the species of the Cercopithecini tribe underwent a very active chromosome evolution, principally by fissions, which increased their chromosome number up to 72. In contrast, all the species of Papionini have fairly similar karyotypes with 42 chromosomes. In animals, nucleolus organizer regions (NORs) are generally considered as instable structures, which frequently vary in size, number, and location at both infra- and interspecific levels. Although in Cercopithecinae the NORs, involved in breaks, exchanges, and translocations, behave like fragile sites in somatic cells, their number and location appear to be very stable between species. Fluorescence in situ hybridization of a 28S rDNA probe on metaphase chromosomes displayed a unique interstitial location in either an acrocentric pair (in 12 species of Cercopithecini) or a metacentric pair (in 6 species of Papionini). A non-exhaustive survey of literature data on NOR location in other primates shows that numerical variations of the NORs principally depend on their location: most multiple NORs are in terminal positions, while almost all unique NORs are in interstitial positions. We propose that this correlation is the consequence of the selection against gametic imbalances involving the chromosomal material distal to the NORs, which is effective when they are interstitially, but not terminally, located. Thus, the consequences of the interstitial NOR instability for reproduction are essentially limited to their size variations, as observed in Cercopithecidae.

scholarly journals Chromosome Mapping of Repetitive Sequences inRachycentron canadum(Perciformes: Rachycentridae): Implications for Karyotypic Evolution and Perspectives for Biotechnological Uses

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Uedson Pereira Jacobina ◽  
Marcelo de Bello Cioffi ◽  
Luiz Gustavo Rodrigues Souza ◽  
Leonardo Luiz Calado ◽  
Manoel Tavares ◽  
...  
Keyword(s):  
Repetitive Sequences ◽  
Chromosome Mapping ◽  
Karyotypic Evolution ◽  
Dapi Staining ◽  
Telomeric Sequences ◽  
Replication Banding ◽  
The Family ◽  
Early Replication

The cobia,Rachycentron canadum, a species of marine fish, has been increasingly used in aquaculture worldwide. It is the only member of the family Rachycentridae (Perciformes) showing wide geographic distribution and phylogenetic patterns still not fully understood. In this study, the species was cytogenetically analyzed by different methodologies, including Ag-NOR and chromomycin A3(CMA3)/DAPI staining, C-banding, early replication banding (RGB), andin situfluorescent hybridization with probes for 18S and 5S ribosomal genes and for telomeric sequences (TTAGGG)n. The results obtained allow a detailed chromosomal characterization of the Atlantic population. The chromosome diversification found in the karyotype of the cobia is apparently related to pericentric inversions, the main mechanism associated to the karyotypic evolution of Perciformes. The differential heterochromatin replication patterns found were in part associated to functional genes. Despite maintaining conservative chromosomal characteristics in relation to the basal pattern established for Perciformes, some chromosome pairs in the analyzed population exhibit markers that may be important for cytotaxonomic, population, and biodiversity studies as well as for monitoring the species in question.

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.

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.

Distribution of Interstitial Telomeric Sequences in Primates and the Pygmy Tree Shrew (Scandentia)

2017 ◽  
Vol 151 (3) ◽  
pp. 141-150 ◽  
Author(s):  
Sofia Mazzoleni ◽  
Odessa Schillaci ◽  
Luca Sineo ◽  
Francesca Dumas
Keyword(s):  
Dna Sequences ◽  
Tree Shrew ◽  
Chromosomal Rearrangements ◽  
Primate Species ◽  
Telomeric Dna ◽  
Erythrocebus Patas ◽  
Telomeric Sequences ◽  
Interstitial Telomeric Sequences ◽  
Cercopithecus Petaurista ◽  
Almost All

It has been hypothesized that interstitial telomeric sequences (ITSs), i.e., repeated telomeric DNA sequences found at intrachromosomal sites in many vertebrates, could be correlated to chromosomal rearrangements and plasticity. To test this hypothesis, we hybridized a telomeric PNA probe through FISH on representative species of 2 primate infraorders, Strepsirrhini (Lemur catta, Otolemur garnettii, Nycticebus coucang) and Catarrhini (Erythrocebus patas, Cercopithecus petaurista, Chlorocebus aethiops, Colobus guereza), as well as on 1 species of the order Scandentia, Tupaia minor, used as an outgroup for primates in phylogenetic reconstructions. In almost all primate species analyzed, we found a telomeric pattern only. In Tupaia, the hybridization revealed many bright ITSs on at least 11 chromosome pairs, both biarmed and acrocentric. These ITS signals in Tupaia correspond to fusion points of ancestral human syntenic associations, but are also present in other chromosomes showing synteny to only a single human chromosome. This distribution pattern was compared to that of the heterochromatin regions detected through sequential C-banding performed after FISH. Our results in the analyzed species, compared with literature data on ITSs in primates, allowed us to discuss different mechanisms responsible for the origin and distribution of ITSs, supporting the correlation between rearrangements and ITSs.

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 Karyotypic characterization of Prochilodus mariae, Semaprochilodus kneri and S. laticeps(Teleostei: Prochilodontidae) from Caicara del Orinoco, Venezuela

2003 ◽  
Vol 1 (1) ◽  
pp. 47-52 ◽  
Author(s):  
Claudio Oliveira ◽  
Mauro Nirchio ◽  
Ángel Granado ◽  
Sara Levy
Keyword(s):  
Chromosome Number ◽  
Chromosome Pair ◽  
Nucleolus Organizer ◽  
Single Chromosome ◽  
Nucleolus Organizer Regions ◽  
The Family ◽  
Structural Chromosome ◽  
Almost All ◽  
Freshwater Environments

Fish of the family Prochilodontidae are considered one of the most important components of commercial and subsistence fishery in freshwater environments in South America. This family consists of 21 species and three genera. In the present study, the karyotypes of Prochilodus mariae, Semaprochilodus kneri, and S. laticeps from Caicara del Orinoco, Bolivar State, Venezuela were studied. The species P. mariae, S. kneri and S. laticeps exhibited 2n=54 chromosomes (40 metacentric and 14 submetacentric), a single chromosome pair with nucleolus organizer regions, and a large amount of heterochromatin found at centromeric and pericentromeric positions in almost all chromosomes. The P. mariae specimens studied displayed 0 to 3 supernumerary microchromosomes. The data obtained here confirm the conservative nature of the chromosome number and morphology of Prochilodontidae and reinforce the hypothesis that small structural chromosome rearrangements were the main cause of the karyotypic diversification seen in this group.

Sign in / Sign up

Export Citation Format

Share Document