Biological aspects of Amazonian fishes. IX. Cytogenetic studies in two species of the genus Semaprochilodus (Pisces, Prochilodontidae)

Genome ◽  
1987 ◽  
Vol 29 (1) ◽  
pp. 1-4 ◽  
Author(s):  
Eliana Feldberg ◽  
Luiz Antonio Carlos Bertollo ◽  
Lurdes Foresti de Almeida Toledo ◽  
Fausto Foresti ◽  
Orlando Moreira Filho ◽  
...  
Keyword(s):  
Diploid Number ◽  
Constitutive Heterochromatin ◽  
Low Frequency ◽  
Nucleolar Organizer ◽  
Hybrid Origin ◽  
Nucleolar Organizer Regions ◽  
Nucleolar Organizing Regions ◽  
Cytogenetic Studies ◽  
Key Words Fish ◽  
Biological Aspects

The karyotype of Semaprochilodus insignis and Semaprochilodus taeniurus were analyzed through the conventional Giemsa staining, C-banding, and the nucleolar organizer regions. The diploid number is the same (2n = 54) in both species, but S. taeniurus shows a chromosomic system of the ZZ/ZW type. This and some other differences between the two karyotypes will be useful in further studies on the possible hybrid origin of the "jaraqui açú," a low frequency form that is observed together with S. insignis and S. taeniurus. Key words: fish, ZZ/ZW system, constitutive heterochromatin, nucleolar organizing regions.

Structure and variability of nucleolar organizer regions in Parodontidae fish

1984 ◽  
Vol 26 (5) ◽  
pp. 564-568 ◽  
Author(s):  
Orlando Moreira-Filho ◽  
Luiz Antonio Carlos Bertollo ◽  
Pedro Manoel Galetti Jr.
Keyword(s):  
Chromosome Pair ◽  
Constitutive Heterochromatin ◽  
Nucleolar Organizer ◽  
Nucleolar Organizer Regions ◽  
Mitotic Chromosomes ◽  
Homozygous Condition ◽  
Nucleolar Organizing Regions ◽  
Nucleolar Chromosome

Nucleolar organizer regions (NORs) were studied in mitotic chromosomes of four species of fish of family Parodontidae: Parodon tortuosus, Apareiodon affinis, Apareiodon ibitiensis, and Apareiodon piracicabae. All four species exhibited only a single nucleolar chromosome pair in their karyotypes. Intraspecific differences were observed in the size of these chromosomes; however, these were not very clear for A. affinis and A. piracicabae, Apareiodon piracicabae exhibited two clearly visible NORs in each of the nucleolar chromosomes, which was the only configuration practically found in this species. This trait therefore predominates in a homozygous condition in the population investigated. Regions of constitutive heterochromatin adjacent to the two NORs were detected. Possible mechanisms that may have originated the two NORs are discussed.Key words: nucleolar organizing regions, fish.

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.

Cytogenetic studies in gomphocerine grasshoppers. II. Chromosomal location of active nucleolar organizing regions

1986 ◽  
Vol 28 (4) ◽  
pp. 540-544 ◽  
Author(s):  
Josefa Cabrero ◽  
Juan Pedro M. Camacho
Keyword(s):  
Chromosomal Location ◽  
Nucleolar Organizer ◽  
X Chromosomes ◽  
Nucleolar Organizing Regions ◽  
Nucleolar Organizing Region ◽  
Primary Activity ◽  
Cytogenetic Studies ◽  
Almost All ◽  
Active Nors

Nucleolar organizing region (NOR) location has been studied in 20 species of gomphocerine grasshoppers. In the 17 species with 2n (♀) = 17, the largest number carry an active NOR on the L2, L3, and X chromosomes. The M4, M5, M6, and S8 show NOR activity in some species, but the L1 and M7 do not carry a NOR in any. While almost all NORs on L2, L3, and X show primary activity, a majority of these on the M4, M5, M6, and S8 are secondary and express a nucleolus only in a minority of male meiocytes. The NORs are located preferentially at particular chromosomal sites; primary active NORs prevail in interstitial locations, while secondary active NORs predominate in paracentromeric locations. In the majority of the species analyzed in this report, primary and secondary active NORs coincide with C-bands. Euchorthippus pulvinatus is an exception; here NORs do not seem to be related to C-bands. However, the nucleolar-associated heterochromatin in this species can be demonstrated by a N-banding technique.Key words: nucleolar organizer, NOR (primary), C-bands, heterochromatin, NOR (secondary).

Chromosome differentiation in the subantarctic Bovichtidae species Cottoperca gobio (Günther, 1861) and Pseudaphritis urvillii (Valenciennes, 1832) (Pisces, Perciformes)

1995 ◽  
Vol 7 (4) ◽  
pp. 381-386 ◽  
Author(s):  
Eva Pisano ◽  
C. Ozouf-Costaz ◽  
J-C. Hureau ◽  
R. Williams
Keyword(s):  
Constitutive Heterochromatin ◽  
Chromosomal Location ◽  
Cytogenetic Study ◽  
Nucleolar Organizer ◽  
Nucleolar Organizer Regions ◽  
Chromosome Differentiation ◽  
Fundamental Number ◽  
Magellan Strait ◽  
Australian Plate ◽  
Acrocentric Chromosomes

A cytogenetic study on the bovichtid species Cottoperca gobio from the Magellan Strait and Pseudaphritis urvillii from Tasmania showed both species have a plesiomorphic number of chromosomes (2n=48). However, C.gobio has a more conservative karyotype composed entirely of acrocentric chromosomes (Fundamental Number=48); the presence of two metacentric pairs in P. urvilli (FN=52) makes this species karyologically more derived. The differences in the number of chromosomal arms, and the chromosomal location of the nucleolar organizer regions indicate karyological divergence in the two separating stocks from which C.gobio and P.urvillii originated. During the diversification of this notothenioid family, probably coincident with the fragmentation of Gondwana, the stock that split off with the Australian Plate gave rise to the Tasmanian species and experienced more chromosomal modifications than the stock from which C. gobio is derived. The pattern of constitutive heterochromatin suggests a possible homology between a pair of chromosomes in bovichtids and other notothenioids.

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.

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