Consulta: subjectFacets:"Sex chromosomes"
Registros recuperados: 16
Data/hora: 09/06/2024 18:14:05

Natural triploidy in Leporinus cf. elongatus bearing sex chromosomes
Provedor de dados: Genetics and Molecular Biology
Autores: Molina,Wagner Franco; Margarido,Vladimir Pavan; Galetti Jr,Pedro Manoel.
Although several cases of natural triploidy in fish have already been described, spontaneous polyploidy in species with differentiated sex chromosomes are rare. We report the occurrence of a triploid fish (3n = 81) Leporinus cf. elongatus, a species characterized by a highly differentiated ZZ/ZW sex chromosome system, from the São Francisco river. The occurrence of a ZZZ triploid adult indicates the viability of this chromosome constitution in this fish.
Tipo: Info:eu-repo/semantics/other
Palavras-chave: Polyploidy; Triploid fish; ZW chromosomes; Sex chromosomes; Anostomidae.
Ano: 2007
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572007000400010

Extensive polymorphism and chromosomal characteristics of ribosomal DNA in the characid fish Triportheus venezuelensis (Characiformes, Characidae)
Provedor de dados: Genetics and Molecular Biology
Autores: Nirchio,Mauro; Oliveira,Claudio; Ferreira,Irani Alves; Granado,Angel; Ron,Ernesto.
The karyotype and chromosomal characteristics of the characid fish Triportheus venezuelensis were investigated using differential staining techniques (C-banding, Ag-NOR staining) and fluorescent in situ hybridization (FISH) with an 18S rDNA probe. The diploid chromosome number (2n = 52), karyotype composition and sex chromosome determination system of the ZZ/ZW type were the same as previously described in other species of the genus Triportheus. However, extensive variation regarding nucleolus organizer regions (NOR) different from other species was observed. 18S rDNA sequences were distributed on nine chromosome pairs, but the number of chromosomes with Ag-NORs was usually lower, reaching a maximum of four chromosomes. When sequential staining experiments...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: 18S rDNA; Ag-NORs; C-band; FISH; Fish cytogenetics; Sex chromosomes.
Ano: 2007
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572007000100007

Cytogenetic analysis of Astylus antis (Perty, 1830) (Coleoptera, Melyridae): Karyotype, heterochromatin and location of ribosomal genes
Provedor de dados: Genetics and Molecular Biology
Autores: Mendes-Neto,Ernani de Oliveira; Vicari,Marcelo Ricardo; Campaner,Carlos; Nogaroto,Viviane; Artoni,Roberto Ferreira; Almeida,Mara Cristina.
Cytogenetic analysis of Astylus antis using mitotic and meiotic cells was performed to characterize the haploid and diploid numbers, sex determination system, chromosome morphology, constitutive heterochromatin distribution pattern and chromosomes carrying nucleolus organizer regions (NORs). Analysis of spermatogonial metaphase cells revealed the diploid number 2n = 18, with mostly metacentric chromosomes. Metaphase I cells exhibited 2n = 8II+Xyp and a parachute configuration of the sex chromosomes. Spermatogonial metaphase cells submitted to C-banding showed the presence of small dots of constitutive heterochromatin in the centromeric regions of nearly all the autosomes and on the short arm of the X chromosome (Xp), as well as an additional band on one of...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Sex chromosomes; Meiosis; Metaphase; FISH; 18S rDNA.
Ano: 2010
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572010000200007

Description of a ZZ/ZW sex chromosome system in Thoracocharax cf. stellatus (Teleostei, Characiformes, Gasteropelecidae)
Provedor de dados: Genetics and Molecular Biology
Autores: Carvalho,Margarida Lima; Oliveira,Claudio; Foresti,Fausto.
The family Gasteropelecidae is composed of three genera and eight species. This study shows that Thoracocharax cf. stellatus has 2n = 52 chromosomes for both sexes. The five males studied showed 8 metacentric, 16 submetacentric, 4 subtelocentric, and 24 acrocentric chromosomes; the seven females showed only one submetacentric chromosome, belonging to pair 11, and one extra acrocentric chromosome, smaller than all the other chromosomes, characterizing the presence of a ZZ/ZW sex chromosome system in this species. Nucleolus organizing regions (NORs) were detected on the short arms of the subtelocentric chromosome pair 13. Constitutive heterochromatin was identified at pericentromeric and terminal positions in almost all chromosomes. The W chromosome was...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Sex chromosomes; ZW; DNA content; Fish; Evolution.
Ano: 2002
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572002000300008

Repetitive DNAs and shrink genomes: A chromosomal analysis in nine Columbidae species (Aves, Columbiformes)
Provedor de dados: Genetics and Molecular Biology
Autores: Kretschmer,Rafael; de Oliveira,Thays Duarte; de Oliveira Furo,Ivanete; Oliveira Silva,Fabio Augusto; Gunski,Ricardo José; del Valle Garnero,Analía; de Bello Cioffi,Marcelo; de Oliveira,Edivaldo Herculano Corrêa; de Freitas,Thales Renato Ochotorena.
Abstract An extensive karyotype variation is found among species belonging to the Columbidae family of birds (Columbiformes), both in diploid number and chromosomal morphology. Although clusters of repetitive DNA sequences play an important role in chromosomal instability, and therefore in chromosomal rearrangements, little is known about their distribution and amount in avian genomes. The aim of this study was to analyze the distribution of 11 distinct microsatellite sequences, as well as clusters of 18S rDNA, in nine different Columbidae species, correlating their distribution with the occurrence of chromosomal rearrangements. We found 2n values ranging from 76 to 86 and nine out of 11 microsatellite sequences showed distinct hybridization signals among...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Birds; FISH; Microsatellites; Sex chromosomes; Chromosomal rearrangements.
Ano: 2018
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572018000100098

Use of chromosome microdissection in fish molecular cytogenetics
Provedor de dados: Genetics and Molecular Biology
Autores: Henning,Frederico; Trifonov,Vladimir; Almeida-Toledo,Lurdes Foresti de.
Chromosome microdissection is a technique in which whole chromosomes or chromosomal segments are dissected under an inverted microscope yielding chromosome-specific sequences. Several protocol modifications introduced during the past 15 years reduced the number of chromosomes required for most applications. This is of particular interest to fish molecular cytogenetics, since most species present highly uniform karyotypes which make impossible the collection of multiple copies of the same chromosome. Probes developed in this manner can be used to investigate chromosome homologies in closely related species. Here we describe a protocol recently used in the gymnotiform species group Eigenmannia and review the major steps involved in the generation of these...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Fluorescence in situ hybridization; Chromosome painting; Sex chromosomes; Cross-FISH.
Ano: 2008
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572008000200022

Chromosome complement and meiosis in three species of the Neotropical bug genus Antiteuchus (Heteroptera, Pentatomidae, Discocephalinae)
Provedor de dados: Genetics and Molecular Biology
Autores: Lanzone,Cecilia; Souza,Maria José de.
Orcein staining of spermatocytes was used to study the meiotic behavior of holocentric chromosomes in three member of the genus Antiteuchus (commonly known as stink bugs). We describe and illustrate the karyotype of Antiteuchus mixtus, A. sepulcralis and A. macraspis which were cytogenetically characterized as having a diploid number of 2n = 14 and an XY sex chromosome system showing pre-reductional meiosis for autosomes and post-reductional meiosis for sex chromosomes. These species were also shown to have a long diffuse stage during meiotic prophase I and aberrant harlequin-type meiocytes. The chiasma frequency was also analyzed for two of the three species studied.
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Spermatogenesis; Holokinetic chromosomes; Sex chromosomes; Meiosis; Diffuse stage.
Ano: 2006
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572006000100011

Evidence of an XX/XY sex chromosome system in the fish Dormitator maculatus (Teleostei, Eleotrididae)
Provedor de dados: Genetics and Molecular Biology
Autores: Oliveira,Claudio; Toledo,Lurdes Foresti de Almeida.
The fish Dormitator maculatus has a chromosomes number of 2n = 46, females having a karyotype of 14 M, 28 SM, 2 ST and 2A and males 13 M, 28 SM, 3 ST and 2A. The presence of a heteromorphic pair in the males and a corresponding homomorphic pair in the females suggest the occurrence of an XX/XY sex chromosome system in D. maculatus. The putative X chromosome has a pericentromeric C-band positive segment and the putative Y chromosome a C-band positive short arm.
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Fish cytogenetics; Karyotypes; Ag-NORs; C-band; Sex chromosomes.
Ano: 2006
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572006000400013

Cytogenetics and DNA barcode reveal an undescribed Apareiodon species (Characiformes: Parodontidae)
Provedor de dados: Genetics and Molecular Biology
Autores: Santos,Emanoel Oliveira dos; Deon,Geize Aparecida; Almeida,Rafael Bonfim de; Oliveira,Ezequiel Aguiar de; Nogaroto,Viviane; Silva,Hugmar Pains da; Pavanelli,Carla Simone; Cestari,Marta Margarete; Bertollo,Luiz Antonio Carlos; Moreira-Filho,Orlando; Vicari,Marcelo Ricardo.
Abstract Parodontidae is a small group of fish and some species are particularly difficult to identify due to the lack of sufficiently consistent morphological traits. Cytogenetically, the species possess 2n = 54 chromosomes and are either sex-homomorphic or sex-heteromorphic (regarding its chromosomes). We evaluated data on color, tooth morphology, cytogenetics, and mitochondrial markers (COI) in Apareiodon specimens from the Aripuanã River (Amazon basin) and the results were compared to other congeneric taxa. Morphological results show an overlap of body color and tooth morphology to other known Apareiodon. The cytogenetics data showed that the 2n = 54 chromosomes, 50 m/sm + 4 st and, a ZZ/ZW sex chromosome system in Apareiodon sp. are common to other...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Chromosomal differentiation; Hidden diversity; Repetitive DNA; Sex chromosomes.
Ano: 2019
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572019000300365

Chromosomal characterization of Amazonian freshwater stingrays with evidence for new karyomorphs and XX/XY sex chromosomes
Provedor de dados: Genetics and Molecular Biology
Autores: Valentim,Francisco Carlos de Souza; Porto,Jorge Ivan Rebelo; Feldberg,Eliana.
Abstract Cytogenetic studies in the subfamily Potamotrygoninae have provided valuable insights into the understanding of the evolution and diversification of its species. In the present study, the chromosomal features of seven nominal potamotrygonin species are provided: Plesiotrygon iwamae (2n=74, FN=120), Potamotrygon amazona (2n=66, FN=107), P. constellata (2n=66, FN=110), P. leopoldi (2n=64, FN=102), P. motoro (2n=66, FN=106) from four different localities, and P. orbignyi (2n=66, FN=106), P. scobina (2n=66, FN=104), from Central Amazon. Additionally, we found a new karyomorph in P. wallacei. We considered the localization of Nucleolus Organizer Regions (NORs), as well as the pattern of constitutive heterochromatin, as species-specific characters. We...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Elasmobranchs; Cytogenetics; Chromosomal rearrangements; Sex chromosomes; Karyotypic diversity.
Ano: 2019
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572019000400578

Karyotype characterization of Anastrepha fruit flies (Diptera: Tephritidae)
Provedor de dados: Neotropical Entomology
Autores: Selivon,Denise; Perondini,André L.P.; Rocha,Lincoln S.
The study comprises the description of the C-banded mitotic chromosomes of five species of Anastrepha, A. amita Zucchi, A. turpiniae Stone, A. zenildae Zucchi, A. grandis (Macquart) and A. leptozona Hendel , and a reanalysis of the chromosomes of three other species, A. distincta Greene, A. obliqua (Macquart) and A. sororcula Zucchi. The species have a diploid number of 12, while A. leptozona has 2n = 10. Heteromorphism of the sex chromosomes is present in all of the species, which have a XY/XX sex chromosome system. A. grandis and A. leptozona have meta and submetacentric autosomes while all of the chromosomes in the other species are acrocentric. The species can be characterized unequivocally by the length and the pattern of blocks of heterochromatin in...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Heterochromatin; Mitotic chromosomes; Sex chromosomes; C-band.
Ano: 2005
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1519-566X2005000200015

Karyotypic and morphological divergence between two cryptic species of Eigenmannia in the Amazon basin with a new occurrence of XX/XY sex chromosomes (Gymnotiformes: Sternopygidae)
Provedor de dados: Neotropical Ichthyology
Autores: Silva,Danillo S.; Peixoto,Luiz A. W.; Pieczarka,Julio C.; Wosiacki,Wolmar B.; Ready,Jonathan S.; Nagamachi,Cleusa Y.
Eigenmannia species are widely distributed in the Neotropics, with eight valid species currently recognized. Populations of Eigenmannia from three locations in the eastern Amazon were investigated using cytogenetic and morphological techniques, revealing two taxa designated here as Eigenmannia sp. "A" and Eigenmannia sp. "B". The species differ in three morphometric characters, two meristic characters, and one osteological character. Eigenmannia sp. "A" presents 2n = 34 (22 m/sm+12 st/a) and Eigenmannia sp. "B" presents 2n = 38 (14 m/sm+24st/a) and simple differentiated sex chromosomes of the type XX/XY. In both species the Constitutive Heterochromatin (CH) rich in A-T bases is distributed in the centromeric region of all chromosomes. Eigenmannia sp. "B"...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Cytogenetics; FISH; Knife fishes; Morphology; Sex chromosomes.
Ano: 2015
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252015000200297

Interspecific chromosomal divergences in the genus Characidium (Teleostei: Characiformes: Crenuchidae)
Provedor de dados: Neotropical Ichthyology
Autores: Alves,José Carlos Pansonato; Paiva,Luiz Ricardo de Souza; Oliveira,Claudio; Foresti,Fausto.
Karyotypes of seven fish species of the genus Characidium, three of them studied for the first time, were characterized using conventional cytogenetic techniques (Giemsa staining, Ag-NOR, and C-banding). All species presented a diploid number of 2n=50, with only metacentric and submetacentric chromosomes, as observed in all Characidium species studied. In two species cells with one to three B chromosomes were observed. All species analyzed have a single NOR-bearing chromosome pair with morphological differences among them. Characidium cf. zebra shows heterochromatic blocks restricted to the pericentromeric regions of all chromosomes denoting the absence of a sex chromosome system. On the other hand, the species Characidium lanei, C. pterostictum, C....
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Karyotypic evolution; Sex chromosomes; B-chromosomes; Ag-NORs.
Ano: 2010
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252010000100010

SEX-DETERMINATION SYSTEMS AND THEIR EVOLUTION: MAMMALS
Provedor de dados: Acta Biológica Colombiana
Autores: COLORADO GARZÓN,FREDY A; MATTA CAMACHO,NUBIA E; SÁNCHEZ,ANTONIO.
Sex-determination methods are very diverse as they have become an enduring research field. Understanding the causes of gonadal development and elucidating the main factors involved in sex-determination of offspring required relating information from far-ranging areas such as cytology, embryology, morphology, molecular biology and even ecology and evolution. This article presents an overview of sex-determination in placental mammals, encompassing several levels of biological organization. The importance of the underlying molecular tools in the context of sex-determination assays and their implications in conservation genetics is also discussed.
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Sex chromosomes; SRY-HMG; Sexual reversion; Genetic conservation and sex-determination.
Ano: 2012
URL: http://www.scielo.org.co/scielo.php?script=sci_arttext&pid=S0120-548X2012000100001

Preferential accumulation of sex and Bs chromosomes in biarmed karyotypes by meiotic drive and rates of chromosomal changes in fishes
Provedor de dados: Anais da Academia Brasileira de Ciências
Autores: MOLINA,WAGNER F.; MARTINEZ,PABLO A.; BERTOLLO,LUIZ A.C.; BIDAU,CLAUDIO J.
Mechanisms of accumulation based on typical centromeric drive or of chromosomes carrying pericentric inversions are adjusted to the general karyotype differentiation in the principal Actinopterygii orders. Here, we show that meiotic drive in fish is also supported by preferential establishment of sex chromosome systems and B chromosomes in orders with predominantly bi-brachial chromosomes. The mosaic of trends acting at an infra-familiar level in fish could be explained as the interaction of the directional process of meiotic drive as background, modulated on a smaller scale by adaptive factors or specific karyotypic properties of each group, as proposed for the orthoselection model.
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Actinopterygii; B chromosomes; Centromeric drive; Chromosome evolution; Sex chromosomes.
Ano: 2014
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652014000401801

Comparative cytogenetic analysis in Erythrolamprus snakes (Serpentes: Dipsadidae) from Argentina
Provedor de dados: Anais da Academia Brasileira de Ciências
Autores: FALCIONE,CAMILA; HERNANDO,ALEJANDRA; BRESSA,MARÍA JOSÉ.
ABSTRACT We described the karyotypes of five snake taxa from Argentina: Erythrolamprus almadensis, E. ceii, E. poecilogyrus caesius, E. p. schotti and E. p. sublineatus, and also intergrading individuals between the last two subspecies by conventional staining, chromosome bandings and fluorescent in situ hybridization (FISH) with 28S ribosomal DNA probes. Erythrolamprus ceii and E. almadensis share a diploid chromosome number of 2n= 28, whereas in E. poecilogyrus intraspecific variations were observed: E. p. caesius has 2n= 28, E. p. schotti and E. p. sublineatus as well as in the intergrading individuals have 2n= 32. In E. almadensis and E. p. caesius, the 2nd and 6th chromosome pairs respectively are heteromorphic by size, morphology and C-banding...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Ag-NOR; C-banding; Xenodontini; Fluorescent banding; RDNA-FISH; Sex chromosomes.
Ano: 2018
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652018000401417