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

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
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.

scholarly journals Cytogenetic analyses in Trinomys (Echimyidae, Rodentia), with description of new karyotypes

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5316 ◽  
Author(s):  
Naiara Pereira Araújo ◽  
Cayo Augusto Rocha Dias ◽  
Rodolfo Stumpp ◽  
Marta Svartman
Keyword(s):  
Chromosome Mapping ◽  
Nucleolar Organizer ◽  
Interspecific Variation ◽  
Nucleolar Organizer Regions ◽  
45S Rdna ◽  
Banding Patterns ◽  
Pericentric Inversions ◽  
Cytogenetic Analyses ◽  
First Time

Trinomys Thomas (1921) is a terrestrial genus of spiny rats endemic to the Brazilian areas of Atlantic Forest and the transitional areas of Cerrado and Caatinga. Although most species have been already karyotyped, the available cytogenetic information is mostly restricted to diploid and fundamental numbers. We analyzed the chromosomes of two Trinomys species: Trinomys moojeni (2n = 56, FN = 106) and Trinomys setosus setosus (2n = 56, FN = 106 and 2n = 56, FN = 108). Our analyses included GTG- and CBG-banding, silver-staining of the nucleolar organizer regions, and chromosome mapping of telomeres and 45S rDNA by fluorescent in situ hybridization (FISH). Comparative GTG- and CBG-banding suggested that the interspecific variation may be due to rearrangements such as pericentric inversions, centromere repositioning, and heterochromatin variation. We report two new karyotypes for T. s. setosus and describe for the first time the banding patterns of the two Trinomys species.

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

2006 ◽  
Vol 66 (1b) ◽  
pp. 191-198 ◽  
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.

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

2004 ◽  
Vol 64 (3b) ◽  
pp. 661-667 ◽  
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.

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

2017 ◽  
Vol 15 (2) ◽  
Author(s):  
Leonardo M. Paiz ◽  
Lucas Baumgärtner ◽  
Weferson J. da Graça ◽  
Vladimir P. Margarido ◽  
Carla S. Pavanelli
Keyword(s):  
Threatened Species ◽  
Diploid Number ◽  
5S Rdna ◽  
Nucleolar Organizer ◽  
First Record ◽  
Nucleolar Organizer Regions ◽  
Environmental Preservation ◽  
Plesiomorphic Character ◽  
Iguaçu River ◽  
Lotic Waters

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.

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

2012 ◽  
Vol 10 (3) ◽  
pp. 623-632 ◽  
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.

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

2013 ◽  
Vol 11 (1) ◽  
pp. 125-131 ◽  
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.

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

1996 ◽  
Vol 74 (1) ◽  
pp. 147-156 ◽  
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.

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

2009 ◽  
Vol 2 (1) ◽  
pp. 91-94 ◽  
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.

Comparative cytogenetics of four species of Thrichomys (Rodentia: Echimyidae)

Genome ◽  
2019 ◽  
Vol 62 (1) ◽  
pp. 31-41
Author(s):  
Naiara Pereira Araújo ◽  
Cibele Bonvicino ◽  
Marta Svartman
Keyword(s):  
Nucleolar Organizer ◽  
Interspecific Variation ◽  
Northeastern Brazil ◽  
Nucleolar Organizer Regions ◽  
Comparative Cytogenetics ◽  
Telomeric Sequences ◽  
Interstitial Telomeric Sequences ◽  
Robertsonian Rearrangements ◽  
Cytogenetic Analyses

Thrichomys Trouessart, 1880 is a genus of echimyid rodents endemic to South America, distributed from northeastern Brazil to Paraguay and Bolivia. Although all the recognized species of this genus have already been karyotyped, detailed comparative cytogenetic analyses have not been performed yet. We karyologically analyzed four species of Thrichomys from different Brazilian states. Our analyses included GTG- and CBG-banding, silver-staining of the nucleolar organizer regions (Ag-NORs), and fluorescent in situ hybridization (FISH) with telomeric and 45S rDNA probes. Comparative GTG-banding suggested that the interspecific variation may result from Robertsonian rearrangements, pericentric and paracentric inversions, centromere repositioning, and heterochromatin variation. FISH with a telomeric probe showed interspecies variation in interstitial telomeric sequences (ITs) distribution. Our results represent the most complete data on the cytogenetics of Thrichomys reported to date and give an insight into the chromosome evolution of this genus.

scholarly journals Sequential Steps of Chromosomal Differentiation in Atlantic Surgeonfishes: Evolutionary Inferences

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Paulo Roberto Antunes de Mello Affonso ◽  
Maria Aparecida Fernandes ◽  
Josivanda Santos Almeida ◽  
Wagner Franco Molina
Keyword(s):  
Molecular Phylogeny ◽  
Nucleolar Organizer ◽  
Chromosomal Evolution ◽  
Nucleolar Organizer Regions ◽  
Similar Distribution ◽  
Noncoding Sequences ◽  
Pericentric Inversions ◽  
Chromosomal Differentiation ◽  
Chromosomal Data

Surgeonfishes are a species-rich group and a major biomass on coral reefs. Three species are commonly found throughout South Atlantic,Acanthurus bahianus,A. chirurgus, andA. coeruleus. In this paper, we present the first cytogenetic data of these species, revealing a sequential chromosomal diversification.A. coeruleuswas characterized by a relatively conserved karyotype evolved by pericentric inversions of some pairs (2n=48, 2sm + 4st + 42a). In contrast, the karyotypes ofA. bahianus(2n=36) andA. chirurgus(2n=34) were highly differentiated by the presence of six large metacentric pairs inA. bahianus(12m + 2sm + 4st + 18a) andA. chirurgus(12m + 2sm + 4st +1 6a) probably derived by chromosomal fusions that corroborate their closer relationship. A discerniblein tandemfusion represents an autapomorphic character toA. chirurgus. In spite of macrostructure variation, single nucleolar organizer regions (NORs) on short arms of a subtelocentric pair and similar distribution of C-bands were observed in the three species. Overlapping of chromosomal data with molecular phylogeny indicated pericentric inversions which took place nearly at 19 Ma while centric fusions are as recent as 5 Ma. A physical mapping of coding and noncoding sequences inAcanthuruscould clarify the role of additional rearrangements during their chromosomal evolution.

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