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Registros recuperados: 7
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Comparative cytogenetic and morphological analysis of Astyanax scabripinnis paranae (Pisces, Characidae, Tetragonopterinae) Genet. Mol. Biol.
Maistro,Edson Luis; Oliveira,Claudio; Foresti,Fausto.
Cytogenetic and morphological studies were carried out on nine local populations of Astyanax scabripinnis paranae. All populations exhibited 2n = 50 chromosomes as well as conspicuous differences involving karyotype morphology, number and position of nucleolar organizer regions (NORs) and amount and/or locations of constitutive heterochromatin blocks. A quantitative study of the cytogenetic data showed that eight populations possessed different karyotypes. Morphological analyses based on nine measurements and two meristic parameters were effective in establishing clear identification of five populations. Comparative analysis of cytogenetic and morphological traits suggests that chromosomal changes have occurred at a more rapid rate than morphological...
Tipo: Info:eu-repo/semantics/article
Ano: 1998 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47571998000200005
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Cytotaxonomic diagnosis of Trichomycterus diabolus (Teleostei: Trichomycteridae) with comments about its evolutionary relationships with co-generic species Neotropical Ichthyology
Torres,Rodrigo A.; Oliveira,Claudio; Foresti,Fausto.
The karyotype and the Ag-NOR location of a sample of Trichomycterus diabolus collected in the córrego Hortelã (Botucatu, São Paulo, Brazil) are described. The species exhibited 2n=56 chromosomes (42 metacentrics, 12 submetacentrics and 2 subtelocentrics) and the nucleolus organizing region located near to the centromere on the long arm of the largest metacentric pair. The presence of 2n=56 chromosomes in T. diabolus is an interesting characteristic since until now all cis-Andean species karyotyped presented 2n=54 chromosomes while almost all trans-Andean species presented different diploid numbers. The possible origin of this unexpected karyotypic form is discussed.
Tipo: Info:eu-repo/semantics/article Palavras-chave: Trichomycterinae; Karyotype; Chromosome evolution; Fish cytogenetic.
Ano: 2004 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252004000300003
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Estimated frequency of B-chromosomes and population density of Astyanax scabripinnis paranae in a small stream Braz. J. Genet.
Porto-Foresti,Fábio; Oliveira,Claudio; Maistro,Edson Luis; Foresti,Fausto.
A study was made of the frequency of B-chromosomes and the population density of Astyanax scabripinnis paranae (Pisces, Characidae, Tetragonopterinae) from three stretches of the Cascatinha stream (Botucatu, SP). In the first stretch the population was estimated to be about 212 individuals and among 35 karyotyped specimens, 23 carried one macro B-chromosome; in the second stretch the population was estimated to be about 650 individuals and among 20 specimens karyotyped, two possessed one macro B-chromosome; in the third stretch the population was estimated to be about 107 individuals and among 10 specimens karyotyped, one carried one macro B-chromosome. A significant difference was observed in the frequency of macro B-chromosomes in females (57%) and males...
Tipo: Info:eu-repo/semantics/article
Ano: 1997 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-84551997000300004
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Nuclear DNA content of thirty species of Neotropical fishes Genet. Mol. Biol.
Carvalho,Margarida Lima; Oliveira,Claudio; Foresti,Fausto.
The present paper reports nuclear DNA content in 30 Neotropical freshwater fish species and summarizes the data on other Neotropical species presented in the literature. Among Neotropical fishes, the nuclear DNA content ranges from 1.04 ± 0.09 pg/nucleus in Corydoras cf. simulatus (2n = 62) to 248.0 pg/nucleus in Lepidosiren paradoxa (2n = 38). A general analysis of the data obtained in the present study for each species showed that DNA measurements were practically constant at the individual level, while significant differences were observed among individuals of the same population. This observation was valid for all species analyzed and was more evident in those species that presented other karyotypic particularities such as sex chromosomes or...
Tipo: Info:eu-repo/semantics/article
Ano: 1998 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47571998000100009
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Populations analysis of the Brazilian Sharpnose Shark Rhizoprionodon lalandii (Chondrichthyes: Carcharhinidae) on the São Paulo coast, Southern Brazil: inferences from mt DNA sequences Neotropical Ichthyology
Mendonça,Fernando Fernandes; Oliveira,Claudio; Gadig,Otto Bismarck Fazzano; Foresti,Fausto.
Sharks of the genus Rhizoprionodon can be considered some of the most important predators along the trophic coastal marine ecosystems and represent an important economic resource for the small-scale fisheries, especially on the Brazilian coastline. In order to analyze the population structure of the shark Rhizoprionodon lalandii of São Paulo, Southeastern coast of Brazil, levels of genetic diversity were identified by nucleotide sequence analyses of the mitochondrial DNA control region. The results obtained from this study present moderate values of haplotype diversity and low nucleotide diversity. Although the AMOVA tests (ΦST = 0.08394, P < 0.01) had shown slightly differences among the studied samples, evidence for the occurrence of population...
Tipo: Info:eu-repo/semantics/article Palavras-chave: D-loop; Haplotypes; Mitochondrial control region; Shark conservation.
Ano: 2009 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252009000200012
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R- and G-band patterns in Astyanax scabripinnis paranae (Pisces, Characiformes, Characidae) Genet. Mol. Biol.
Maistro,Edson Luis; Foresti,Fausto; Oliveira,Claudio.
The absence of longitudinal bands in fish chromosomes has been associated with technical problems in chromosome preparations or the absence of a structural compartmentalization in the fish genome. In the present study, a R-banding pattern was obtained using a replication banding technique by in vivo treatment with 5-bromodeoxyuridine (5-BrdU). G-banding patterns were obtained after trypsin treatment and also after chromosome cleavage by in situ treatment with the restriction endonuclease BamHI. A similar G-banding pattern was also obtained after cleavage with the endonuclease HinfI. Presence of a resolute R- and G-banding patterns shows that Astyanax scabripinnis paranae chromosomes could present an isochore-like structure similar to that found in other...
Tipo: Info:eu-repo/semantics/article
Ano: 1999 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47571999000200011
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Surprising genomic diversity in the Neotropical fish Synbranchus marmoratus (Teleostei: Synbranchidae): how many species? Neotropical Ichthyology
Torres,Rodrigo Augusto; Roper,James Joseph; Foresti,Fausto; Oliveira,Claudio.
Chromosomes and nuclear DNA content variation in the eel Synbranchus marmoratus were studied in seven samples taken from rio Paraguay and rio Paraná basins to examine whether karyotype and nuclear DNA content variations could offer useful information for the characterization of independent evolutionary lineages in the genus and construction of evolutionary and biogeographical hypotheses. The occurrence of different karyotypes was already described for this species; however, a new cytotype from rio Miranda was discovered. Nuclear DNA content showed a wide variation among samples and individuals, ranging from 5.2 to 9.1 pg of DNA/nuclei. An analysis of variance confirmed the occurrence of significant differences among samples. In a deeper series of analyses,...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Fish DNA; Chromosomes; Genome diversity; Karyotype; Synbranchus marmoratus.
Ano: 2005 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252005000200005
Registros recuperados: 7
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