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| Registros recuperados: 45 | |
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| Pereira Sühsner,Claudia; Honfi,Ana I; Ferrucci,María S; Deginani,Norma. |
| El presente trabajo tuvo por objeto caracterizar cariológicamente las especies del género Passiflora L., subgénero Passiflora, del Distrito Félix Pérez Cardozo, Guairá, Paraguay. Por primera vez, se da a conocer el número cromosómico en meiosis 2n = 9II para P. alata Curtis y P. caerulea L. También, se confirma el número cromosómico de 2n = 9II para P. edulis Sims. El comportamiento meiótico en todas las especies estudiadas fue normal, con segregación regular de los cromosomas. La asociación cromosómica frecuentemente encontrada en diacinesis y metafase I fue de bivalentes. Las pocas irregularidades meióticas observadas consistieron en cromosomas rezagados en anafase I y fases asincrónicas en meiosis II, sin embargo, la viabilidad de polen es alta, entre... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Meiosis; Passiflora; Viabilidad del polen. |
| Ano: 2016 |
URL: http://www.scielo.org.ar/scielo.php?script=sci_arttext&pid=S0011-67932016000100004 |
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| Schneider,Marielle Cristina; Carraro,Bianca Pierina; Cella,Doralice Maria; Matiello,Rodrigo Rodrigues; Artoni,Roberto Ferreira; Almeida,Mara Cristina. |
| In this work we describe the cytogenetic analyses performed in specimens of Astylus variegatus (Germar, 1824) collected in two localities: one area of natural vegetation and one of agricultural crops, where agrochemical products were used. Astylus variegatus had karyotypes with 2n(male) = 16+Xy p and 2n (female) = 16+XXp, with exclusively metacentric chromosomes. Pachytene spermatocytes showed synapsed autosomal bivalents and non-associated sex chromosomes. In diplotene, the autosomal bivalents exhibited one or two terminal chiasmata and the Xy p had a typical parachute configuration. In meiotic cells of some specimens, an extra chromosome, interpreted as a B chromosome, was observed. C-banding showed constitutive heterochromatin in the pericentromeric... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: B chromosome; Constitutive heterochromatin; Karyotype; Meiosis; Ag-NORs. |
| Ano: 2007 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572007000400023 |
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| Stavale,Leila Miguel; Schneider,Marielle Cristina; Araujo,Douglas; Brescovit,Antonio Domingos; Cella,Doralice Maria. |
| Theridiidae is a derived family within the Araneoidea clade. In contrast to closely related groups, the 2n(male) = 20+X1X2 with acro/telocentric chromosomes is the most widespread karyotype among the theridiid spiders. In this work, the cytogenetic analysis of Argyrodes elevatus revealed original chromosome features different from those previously registered for Theridiidae, including the presence of 2n(male) = 20+X with meta/submetacentric chromosomes. Most individuals of Nesticodes rufipes showed family conserved karyotype characteristics. However, one individual had a 2n(male) = 24 due to the presence of an extra chromosome pair, which exhibited regular behavior and reductional segregation during meiosis. After silver staining, mitotic cells exhibited... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Chromosome morphology; Cytogenetic; Meiosis; Nucleolar organizer region; Sex chromosome system. |
| Ano: 2010 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572010000400012 |
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| Bhaumik,Pranami; Ghosh,Priyanka; Ghosh,Sujay; Feingold,Eleanor; Ozbek,Umut; Sarkar,Biswanath; Dey,Subrata Kumar. |
| Abstract Alzheimer's disease and Down syndrome often exhibit close association and predictively share common genetic risk-factors. Presenilin-1 (PSEN-1) and Apolipoprotein E (APOE) genes are associated with early and late onset of Alzheimer's disease, respectively. Presenilin −1 is involved in faithful chromosomal segregation. A higher frequency of the APOE ε4 allele has been reported among young mothers giving birth to Down syndrome children. In this study, 170 Down syndrome patients, grouped according to maternal meiotic stage of nondisjunction and maternal age at conception, and their parents were genotyped for PSEN-1 intron-8 and APOE polymorphisms. The control group consisted of 186 mothers of karyotypically normal children. The frequencies of the... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Chromosome; Genetic polymorphism; Karyotype; Meiosis; Microsatellite markers. |
| Ano: 2017 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572017000400577 |
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| 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 |
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| Speranza,Pablo; Vaio,Magdalena; Mazzella,Cristina. |
| Paspalum quadrifarium Lam. is a bunchgrass native to Uruguay, Argentina, and southern Brazil. Diploid, triploid, tetraploid and hexaploid cytotypes have been reported for this species of the Quadrifaria group of Paspalum. In this group, a high degree of cytogenetic homology between the genomes of several diploid species has been reported, based on meiotic pairing in interspecific hybrids; multivalent associations would thus be expected in polyploid hybrids. Karyotype analysis could provide useful information about the genomic architecture of polyploid plants; however, the fully condensed mitotic chromosomes of Paspalum do not provide enough morphological features for such an analysis. In this paper, we used mitotic prometaphase chromosomes treated with 70%... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Karyotype; Meiosis; Prometaphase; Grasses; Paspalum. |
| Ano: 2003 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572003000400013 |
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| Mendes-Bonato,Andréa Beatriz; Pagliarini,Maria Suely; Valle,Cacilda Borges do. |
| This paper reports a case of abnormal spindle orientation during microsporogenesis in an interspecific hybrid of the tropical grass Brachiaria. In the affected plant, prophase I was normal. In metaphase I, bivalents were regularly co-oriented but distantly positioned and spread over the equatorial plate. In anaphase I, chromosomes failed to converge into focused poles due to parallel spindle fibers. As a consequence, in telophase I, an elongated nucleus or several micronuclei were observed in each pole. In the second division, the behavior was the same, leading to polyads with several micronuclei. A total of 40% of meiotic products were affected. The use of this hybrid in production systems needing good-quality seeds is discussed. |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Brachiaria; Interspecific hybrid; Meiosis; Spindle abnormality; Tropical grass. |
| Ano: 2006 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572006000100023 |
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| Pearson,Peter L.; Madan,Kamlesh. |
| Abstract Polyploidy does not usually occur in germinal cells of mammals and other higher vertebrates. We describe a unique example of mosaic autotetraploidy in the meiosis of a human male. Although the original observations were made in the late 1960s, we did not publish them at that time, because we expected to detect further examples that could be described together. However, this did not occur and we have now decided to make the observations available to demonstrate that polyploidy in mammalian male meiosis can arise at a higher frequency than expected by random polyploidization of individual meiotic cells, by either DNA duplication or cell fusion prior to synapsis. This is the first description of a population of primary spermatocytes exhibiting... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Polyploidy; Meiosis; Human; Male. |
| Ano: 2018 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572018000300410 |
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| Fradkin,Maia; Greizerstein,Eduardo; Paccapelo,Héctor; Ferreira,Víctor; Grassi,Ezequiel; Poggio,Lidia; Ferrari,María Rosa. |
| We studied three different tricepiros: (Don Santiago x Don Noé), (Cumé x Horovitz) and (Cumé x Don Noé). The tricepiro (Don Santiago x Don Noé) was obtained by crossing the triticale Don Santiago INTA (AABBRR, 2n = 6x = 42) with the trigopiro Don Noé INTA (AABBDDJJ, 2n = 8x = 56). The number of chromosomes for the F1 was 2n = 49, the most frequent meiotic configuration being 14 bivalents and 21 univalents. The univalents were situated in the periphery of the equatorial plane, whereas the bivalents were located in the central zone. The chromatids in some of the univalents split when bivalents underwent reductional division in anaphase I. There were few laggard chromosomes or chromatids at this phase. The number of chromosomes (2n = 48-58) was high and... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Hybrids; Meiosis; Tricepiro; Univalents; Reductional division. |
| Ano: 2009 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572009000400022 |
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| RISSO-PASCOTTO, C.; MENDES-BONATO, A. B.; PAGLIARINI, M. S.; VALLE, C. B. do. |
| Em gramíneas forrageiras do gênero Brachiaria, populações poliplóides naturais são abundantes e geralmente apomíticas, enquanto as diploídes, que se reproduzem sexualmente, são raras. Considerando-se a estreita correlação existente entre poloploidia e apomixia neste gênero, e a necessidade de identificação de genótipos sexuais compatíveis para o sucesso de hibridação, conhecimentos de características citológicas básicas como modo de reprodução, comportamento meiótico e nível de ploidia tornam-se essenciais para direcionar os programas de melhoramento. Durante análises desenvolvidas na Universidade Estadual de Maringá, com acessos de várias espécies de uma coleção de germoplasma, mantida na Embrapa Gado de Corte, três acessos, sendo um B.... |
| Tipo: Boletim de Pesquisa e Desenvolvimento (INFOTECA-E) |
Palavras-chave: Braquiária; Feed grasses.; Brachiaria Decumbens; Brachiaria Ruziziensis; Citogenética Vegetal; Gramínea Forrageira; Meiose; Poliploidia.; Cytogenetics; Polyploidy.; Meiosis. |
| Ano: 2003 |
URL: http://www.infoteca.cnptia.embrapa.br/infoteca/handle/doc/324062 |
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| Registros recuperados: 45 | |
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