Cytogenetics of Gymnogeophagus setequedas (Cichlidae: Geophaginae), with comments on its geographical distribution

ABSTRACT We provide cytogenetic data for the threatened species Gymnogeophagus setequedas, and the first record of that species collected in the Iguaçu River, within the Iguaçu National Park’s area of environmental preservation, which is an unexpected occurrence for that species. We verified a diploid number of 2n = 48 chromosomes (4sm + 24st + 20a) and the presence of heterochromatin in centromeric and pericentromeric regions, which are conserved characters in the Geophagini. The multiple nucleolar organizer regions observed in G. setequedas are considered to be apomorphic characters in the Geophagini, whereas the simple 5S rDNA cistrons located interstitially on the long arm of subtelocentric chromosomes represent a plesiomorphic character. Because G. setequedas is a threatened species that occurs in lotic waters, we recommend the maintenance of undammed environments within its known area of distribution.

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Cytogenetic and molecular analyses in troglobitic and epigean species of Pimelodella (Siluriformes: Heptapteridae) from Brazil

Neotropical Ichthyology ◽

10.1590/s1679-62252012005000020 ◽

2012 ◽

Vol 10 (3) ◽

pp. 623-632 ◽

Cited By ~ 3

Author(s):

Bianca Dazzani ◽

Caroline Garcia ◽

Marilena Peixoto ◽

Eleonora Trajano ◽

Lurdes Foresti de Almeida-Toledo

Keyword(s):

Diploid Number ◽

Evolutionary Relationship ◽

5S Rdna ◽

Nucleolar Organizer ◽

Molecular Data ◽

Nucleolar Organizer Regions ◽

Minimum Evolution ◽

Pcr Rflp ◽

Cytogenetic Analyses ◽

Atpase 6

Samples from seven different locations of the genus Pimelodella were genetically examined, two caves (exclusively subterranean, upper Tocantins River and São Francisco River) and five epigean (from upper Paraná River basin). Cytogenetic analyses revealed the same diploid number (2n=46) for all species besides similarities in both number and location of nucleolar organizer regions and C bands. FISH with 5S rDNA probes and CMA3 staining indicated significant differences among the studied species. Application of PCR-RFLP in ATPase 6 and 8 mitochondrial genes allowed building a minimum evolution phenogram identifying the close evolutionary relationship among groups. Both chromosomal and molecular data were useful to infer the relationships among studied Pimelodella species.

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Comparative cytogenetic analysis of Avena macrostachya and diploid C-genome Avena species

Genome ◽

10.1139/g09-089 ◽

2010 ◽

Vol 53 (2) ◽

pp. 125-137 ◽

Cited By ~ 14

Author(s):

Ekaterina D. Badaeva ◽

Olga Yu. Shelukhina ◽

Axel Diederichsen ◽

Igor G. Loskutov ◽

Vitaly A. Pukhalskiy

Keyword(s):

5S Rdna ◽

Nucleolar Organizer ◽

Nucleolar Organizer Regions ◽

Rrna Gene ◽

Avena Species ◽

Rdna Sites ◽

C Genome ◽

Genome Group ◽

26S Rrna

The chromosome set of Avena macrostachya Balansa ex Coss. et Durieu was analyzed using C-banding and fluorescence in situ hybridization with 5S and 18S-5.8S-26S rRNA gene probes, and the results were compared with the C-genome diploid Avena L. species. The location of major nucleolar organizer regions and 5S rDNA sites on different chromosomes confirmed the affiliation of A. macrostachya with the C-genome group. However, the symmetric karyotype, the absence of “diffuse heterochromatin”, and the location of large C-band complexes in proximal chromosome regions pointed to an isolated position of A. macrostachya from other Avena species. Based on the distribution of rDNA loci on the C-genome chromosomes of diploid and polyploid Avena species, we propose a model of the chromosome alterations that occurred during the evolution of oat species.

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Cytogenetics of two sympatric Corydoras species (pisces, siluriformes, challichtyidae) of Southern Brazil

Brazilian Journal of Biology ◽

10.1590/s1519-69842006000200002 ◽

2006 ◽

Vol 66 (1b) ◽

pp. 191-198 ◽

Cited By ~ 6

Author(s):

R. F. Artoni ◽

M. L. Terêncio ◽

M. R. Vicari ◽

M. C. A. Matiello ◽

M. M. Cestari ◽

...

Keyword(s):

In Situ Hybridization ◽

Diploid Number ◽

Constitutive Heterochromatin ◽

Nucleolar Organizer ◽

Nucleolar Organizer Regions ◽

Great Similarity ◽

Southern Brazil ◽

Rdna Probe ◽

Karyotypic Formula

Karyotypic data are presented for two sympatric Corydoras species of the Lagoa Dourada, namely, C. ehrhadti and C. paleatus, which are found in the upper Tibagi river basin (Ponta Grossa, State of Paraná, Brazil). The same diploid number and karyotypic formula were observed in both species/populations. A great similarity in the constitutive heterochromatin distribution and in the activity of nucleolar organizer regions was also found. The use of in situ hybridization with a fluorescent 18S rDNA probe allowed for the identification of the species/populations through the location of ribosomal sites.

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Cytogenetics of the Brazilian whiptail lizard Cnemidophorus littoralis (Teiidae) from a restinga area (Barra de Maricá) in Southeastern Brazil

Brazilian Journal of Biology ◽

10.1590/s1519-69842004000400014 ◽

2004 ◽

Vol 64 (3b) ◽

pp. 661-667 ◽

Cited By ~ 4

Author(s):

D. Peccinini-Seale ◽

C. F. D. Rocha ◽

T. M. B. Almeida ◽

A. F. B. Araújo ◽

M. A. De Sena

Keyword(s):

New Species ◽

Sex Determination ◽

Diploid Number ◽

Nucleolar Organizer ◽

Southeastern Brazil ◽

Nucleolar Organizer Regions ◽

Interphase Nuclei ◽

Determination Mechanism ◽

A New Species ◽

Chromosomal Sex Determination

Chromosomes of Cnemidophorus littoralis, a new species of teiid lizard recently described, were studied. The animals are from a restinga area in Barra de Maricá, RJ. The karyotype presents a diploid number of 2n = 46 chromosomes and a chromosomal sex determination mechanism of the type XX:XY. Nucleolar organizer regions, Ag-NORs, are at the sixth pair of chromosomes; there is variability of size and number of the Ag-stained nucleoli on the 50 interphase nuclei for each specimen analyzed. These nucleoli are related to NOR patterns that also demonstrated variability in size and number. This paper presents the first description of the karyotype of Cnemidophorus littoralis and of a chromosomal sex determination mechanism of the XX:XY type in the genus Cnemidophorus from Southeastern Brazil.

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Diversity and chromosomal evolution in the genus Ancistrus Kner, 1854 (Loricariidae: Ancistrini) from three hydrographic basins of Mato Grosso State, Brazil

Neotropical Ichthyology ◽

10.1590/s1679-62252013000100015 ◽

2013 ◽

Vol 11 (1) ◽

pp. 125-131 ◽

Cited By ~ 7

Author(s):

Sandra Mariotto ◽

Liano Centofante ◽

Orlando Moreira-Filho

Keyword(s):

Diploid Number ◽

Nucleolar Organizer ◽

Single Species ◽

Chromosomal Evolution ◽

Nucleolar Organizer Regions ◽

Mitotic Chromosomes ◽

Evolutionary Mechanisms ◽

Mato Grosso ◽

Silver Nitrate Staining ◽

Cytogenetic Analyses

Cytogenetic analyses were carried out in 117 specimens of seven species of the genus Ancistrus from three hydrographic in Mato Grosso State: Paraguay, Araguaia-Tocantins and Amazon basins. Conventional cytogenetic techniques were used to obtain mitotic chromosomes. C-banding was performed to detect heterochromatic regions and silver nitrate staining was used to identify nucleolar organizer regions (Ag-NORs). The counted and paired chromosomes revealed diploid numbers ranging from 2n = 40 to 2n = 54 with karyotype formulae varying from FN = 80 to FN = 86. Single marks in distinct chromosomes identified the nucleolar organizer regions. The constitutive heterochromatin was scarce in the diploid number from 2n = 50 to 2n = 54 and conspicuous blocks were observed in a single species with 2n = 40 chromosomes. These data corroborate the hypotheses of reduction of diploid number in species with derived features such as presence of sex chromosomes and polymorphisms, besides allowing inferences about the evolutionary mechanisms and the ancestor karyotype that favored the diversification of this important genus in the tribe Ancistrini.

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Karyotype Patterns ofHypsolebias antenori(Cyprinodontiformes: Rivulidae): An Endangered Killifish of the Semiarid Region of Brazil

The Scientific World JOURNAL ◽

10.1155/2014/862434 ◽

2014 ◽

Vol 2014 ◽

pp. 1-6 ◽

Cited By ~ 4

Author(s):

Wallace Silva do Nascimento ◽

Juliana Galvão Bezerra ◽

Paulo Augusto Lima-Filho ◽

Maria Emília Yamamoto ◽

Sathyabama Chellappa ◽

...

Keyword(s):

Diploid Number ◽

Nucleolar Organizer ◽

Dynamic Environments ◽

Northeastern Brazil ◽

Semiarid Region ◽

Nucleolar Organizer Regions ◽

Short Life ◽

Annual Fish ◽

Pericentric Inversions ◽

Taxonomic Markers

Annual fish which belong to the order Cyprinodontiformes constitute an excellent model for evolutionary studies. their short life cycle, distribution in ecologically dynamic environments, and low agility make them favorable for genetic analyses. The speciesHypsolebias antenori(Rivulidae), encountered in seasonal pools located in the semiarid region of Northeastern Brazil, has been the object of surveys with a view to study its ecological and behavioral aspects. This study reports on the karyotype patterns of this species, which represents the first contribution to the cytogenetics of this genus. The karyotype of this species is composed of 2n = 48 chromosomes (6m + 4sm + 36st; NF = 96); the heterochromatic regions are located in centromeric or pericentromeric position and are more pronounced in the nucleolar organizer regions. Two sites Ag-NORs/CMA+/DAPI were identified in the short arms of pairs 2 (metacentric) and 21 (subtelocentric). Unlike the other species of this family which show an evolution modulated by events of centric fusions,H. antenorishows the maintenance of a basal diploid number and the large number of bibrachial elements indicates karyotypic diversification derived by pericentric inversions. Cytogenetic analyzes in this species will provide new taxonomic markers capable of being utilized in conservation issues and systematics.

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Cytogenetic characterization of Aloysia virgata Ruiz and Pavan (Verbenaceae)

Brazilian Archives of Biology and Technology ◽

10.1590/s1516-89132009000400013 ◽

2009 ◽

Vol 52 (4) ◽

pp. 893-899

Author(s):

Aline Dias Brandão ◽

Lyderson Facio Viccini ◽

Shirlei Maria Recco-Pimentel

Keyword(s):

Interphase Nucleus ◽

5S Rdna ◽

Nucleolar Organizer ◽

Nucleolar Organizer Regions ◽

Meiotic Behavior ◽

Meiotic Analysis ◽

Chromosomal Pair ◽

Cytogenetic Characterization

Since previous cytogenetic reports of Aloysia have only described the meiotic behavior and chromosomal number of some species, the aim of this work was to provide detailed cytogenetic description of Aloysia virgata that would contribute to the understanding of the taxonomical organization of the Verbenaceae. Aloysia virgata had a karyotype with 2n = 36 metacentric chromosomes, all with similar size. The large amount of heterochromatin seen after Giemsa staining was confirmed by C-banding. Four nucleolar organizer regions (NORs) were detected with an rDNA 45S probe in two homologous pairs and two sites of 5S rDNA located on one chromosomal pair were detected by fluorescence in situ hybridization. The interphase nucleus was classified as semi-reticulate. Meiotic analysis showed a normal chromosomal behavior, with 18 bivalents in some parts of prophase I and in metaphase I. The number of chromosomes, NORs and 5S rDNA segments did not exclude a possible polyploid origin.

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Chromosome-banding study of the Alaska blackfish, Dallia pectoralis (Euteleostei: Esocae), with implications for karyotype evolution and relationship of esocoid fishes

Canadian Journal of Zoology ◽

10.1139/z96-019 ◽

1996 ◽

Vol 74 (1) ◽

pp. 147-156 ◽

Cited By ~ 8

Author(s):

E. J. Crossman ◽

P. Ráb

Keyword(s):

Diploid Number ◽

Chromosomal Polymorphism ◽

Nucleolar Organizer ◽

River System ◽

Nucleolar Organizer Regions ◽

Yukon River ◽

Colville River ◽

Relationship Of ◽

Number Of Individuals ◽

Banding Study

Chromosomes of Dallia pectoralis from two widely separated locations in Alaska (Yukon River system and Colville River) were analyzed by Giemsa staining, C-banding, and Chromomycin A3 fluorescence. The karyotype was redescribed more precisely. The diploid number 2n = 78 was found, but a significant number of cells with 74–77 chromosomes in individuals from the Yukon River indicate chromosomal polymorphism in the species. The diploid chromosome number of individuals from Colville River was constant (2n = 74). Colville River individuals had one more pair of metacentrics than Yukon River individuals with 2n = 76. The distribution of heterochromatin was nearly the same, and the number and location of nucleolar organizer regions (NORs) was identical. The variation (71–79) may be attributable to the association of NOR-bearing chromosomes or to chromosomal distinction between populations in the two rivers. The results suggest close relationships among all the species of Umbra, a closer relationship between Novumbra and Dallia than either bears to Umbra, and a possible closer relationship between Umbra and Esox than between Esox and Novumbra plus Dallia.

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Conserved Cytogenetic Features in the Amazonian Arapaima, Arapaima gigas (Schinz 1822) from Jamari River, Rondônia–Brazil

The Open Biology Journal ◽

10.2174/1874196700902010091 ◽

2009 ◽

Vol 2 (1) ◽

pp. 91-94 ◽

Cited By ~ 6

Author(s):

Renata da Rosa ◽

Marceléia Rubert ◽

Mauro Caetano-Filho ◽

Lucia Giuliano-Caetano

Keyword(s):

Diploid Number ◽

Nucleolar Organizer ◽

Pericentromeric Region ◽

Nucleolar Organizer Regions ◽

Fluorochrome Staining ◽

Arapaima Gigas ◽

Chromosomal Pair ◽

Silver Nitrate Staining ◽

Subterminal Region ◽

Secondary Constrictions

Specimens of Arapaima gigas from Jamari River (RO) were cytogenetically analyzed. A diploid number of 2n=56 chromosomes was found (28m-sm + 28st-a). Secondary constrictions were observed on the short arms of chromosome 3. Nucleolar Organizer Regions (NORs) were detected at the subterminal region on short arms of the third chromosomal pair by both silver nitrate staining and FISH with 45S rDNA probe, being equivalent to secondary constrictions. The ribosomal sites were also characterized by size heteromorphism and presence of CMA3+/DAPI- blocks. The constitutive heterochromatin was located at pericentromeric region of some chromosomes. After sequential Cbanding and base-specific fluorochromes staining, most of the heterochromatins proved to be neutral, i.e., with similar amounts of AT and GC bases. Nonetheless, some heterochromatic regions were marked by GC-specific fluorochromes in one chromosomal pair and by AT-specific fluorochrome staining on two pairs. The present data are in agreement with previous reports in populations from Araguaya River, indicating that conserved cytogenetic features are present in this important fish species.

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Ancient Origin of Two 5S rDNA Families Dominating in the Genus Rosa and Their Behavior in the Canina-Type Meiosis

Frontiers in Plant Science ◽

10.3389/fpls.2021.643548 ◽

2021 ◽

Vol 12 ◽

Author(s):

Radka Vozárová ◽

Veit Herklotz ◽

Aleš Kovařík ◽

Yuri O. Tynkevich ◽

Roman A. Volkov ◽

...

Keyword(s):

Diploid Species ◽

5S Rdna ◽

Woody Species ◽

Nucleolar Organizer ◽

Gene Families ◽

Nucleolar Organizer Regions ◽

Intergenic Spacers ◽

History Of ◽

35S Rdna ◽

Distinct Distribution

The genus Rosa comprises more than 100 woody species characterized by intensive hybridization, introgression, and an overall complex evolutionary history. Besides many diploid species (2n = 2x = 14) polyploids ranging from 3x to 10x are frequently found. Here we analyzed 5S ribosomal DNA in 19 species covering two subgenera and the major sections within subg. Rosa. In addition to diploids and polyploids with regular meiosis, we focused on 5x dogroses (Rosa sect. Caninae), which exhibit an asymmetric meiosis differentiating between bivalent- and univalent-forming chromosomes. Using genomic resources, we reconstructed 5S rDNA units to reveal their phylogenetic relationships. Additionally, we designed locus-specific probes derived from intergenic spacers (IGSs) and determined the position and number of 5S rDNA families on chromosomes. Two major 5S rDNA families (termed 5S_A and 5S_B, respectively) were found at variable ratios in both diploid and polyploid species including members of the early diverging subgenera, Rosa persica and Rosa minutifolia. Within subg. Rosa species of sect. Rosa amplified the 5S_A variant only, while taxa of other sections contained both variants at variable ratios. The 5S_B family was often co-localized with 35S rDNA at the nucleolar organizer regions (NOR) chromosomes, whereas the co-localization of the 5S_A family with NOR was only exceptionally observed. The allo-pentaploid dogroses showed a distinct distribution of 5S rDNA families between bivalent- and univalent-forming chromosomes. In conclusion, two divergent 5S rDNA families dominate rose genomes. Both gene families apparently arose in the early history of the genus, already 30 myrs ago, and apparently survived numerous speciation events thereafter. These observations are consistent with a relatively slow genome turnover in the Rosa genus.

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