Navegando por Palavras-chave "cytogenetic"
Agora exibindo 1 - 6 de 6
Resultados por página
Opções de Ordenação
- ItemAcesso aberto (Open Access)Chromosomes of Theridiidae spiders (Entelegynae): interspecific karyotype diversity in Argyrodes and diploid number intraspecific variability in Nesticodes rufipes(Sociedade Brasileira de Genética, 2010-01-01) Stavale, Leila Miguel; Schneider, Marielle Cristina [UNIFESP]; Araujo, Douglas; Brescovit, Antonio Domingos; Cella, Doralice Maria; Universidade Estadual Paulista (UNESP); Universidade Federal de São Paulo (UNIFESP); Universidade Estadual de Mato Grosso do Su; Instituto Butantan Laboratório de ArtrópodesTheridiidae 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 NORs localized on the terminal regions of the short arms of pairs 2, 3, and 4 of A. elevatus and on the terminal regions of long arms of pair 4 of N. rufipes. The comparative analysis with data from phylogenetically related species allowed the clarification of the origin of the interspecific and intraspecific chromosome variability observed in Argyrodes and in N. rufipes, respectively.
- ItemSomente MetadadadosComplex meiotic configuration of the holocentric chromosomes: the intriguing case of the scorpion Tityus bahiensis(Springer, 2009-10-01) Schneider, Marielle Cristina [UNIFESP]; Zacaro, Adilson Ariza; Pinto-da-Rocha, Ricardo; Candido, Denise Maria; Cella, Doralice Maria; Universidade Federal de São Paulo (UNIFESP); Univ Estadual Paulista; Universidade Federal de Viçosa (UFV); Universidade de São Paulo (USP); Inst ButantanMitotic and meiotic chromosomes of Tityus bahiensis were investigated using light (LM) and transmission electron microscopy (TEM) to determine the chromosomal characteristics and disclose the mechanisms responsible for intraspecific variability in chromosome number and for the presence of complex chromosome association during meiosis. This species is endemic to Brazilian fauna and belongs to the family Buthidae, which is considered phylogenetically basal within the order Scorpiones. in the sample examined, four sympatric and distinct diploid numbers were observed: 2n = 5, 2n = 6, 2n = 9, and 2 = 10. the origin of this remarkable chromosome variability was attributed to chromosome fissions and/or fusions, considering that the decrease in chromosome number was concomitant with the increase in chromosome size and vice versa. the LM and TEM analyses showed the presence of chromosomes without localised centromere, the lack of chiasmata and recombination nodules in male meiosis, and two nucleolar organiser regions carrier chromosomes. Furthermore, male prophase I cells revealed multivalent chromosome associations and/or unsynapsed or distinctly associated chromosome regions (gaps, less-condensed chromatin, or loop-like structure) that were continuous with synapsed chromosome segments. All these data permitted us to suggest that the chromosomal rearrangements of T. bahiensis occurred in a heterozygous state. A combination of various factors, such as correct disjunction and balanced segregation of the chromosomes involved in complex meiotic pairing, system of achiasmate meiosis, holocentric nature of the chromosomes, population structure, and species dispersion patterns, could have contributed to the high level of chromosome rearrangements present in T. bahiensis.
- ItemSomente MetadadadosKaryotype Conservation in 2 Populations of the Parthenogenetic Scorpion Tityus serrulatus (Buthidae): rDNA and Its Associated Heterochromatin Are Concentrated on Only One Chromosome(Oxford Univ Press Inc, 2010-07-01) Schneider, Marielle C. [UNIFESP]; Cella, Doralice M.; Universidade Federal de São Paulo (UNIFESP); Universidade de São Paulo (USP)Within the order Scorpiones, the parthenogenetic mode of reproduction has been described for 11 species, 6 of which belong to the genus Tityus. in this work, an investigation of the chromosome characteristics of 2 populations of Tityus serrulatus, the first scorpion species known to be thelytokously parthenogenetic, is described. An analysis of 40 individuals revealed holocentric chromosomes of large, medium, and small sizes and an invariable diploid number of 2n = 12. in addition to the conserved macrokaryotype structure, specific chromosome regions also appeared unchanged within and between the samples studied; that is, each sample displayed only one chromosome carrier of the active nucleolar organizer region containing ribosomal genes (5.8S, 18S, and 28S) and AT-rich heterochromatin associated with the ribosomal DNA. the high conservation of the chromosomal features observed in T. serrulatus differed from that verified in certain species of other groups of animals that possess both holocentric chromosomes and parthenogenetic reproduction. Moreover, the cytogenetic results obtained herein permit us to suggest how the eggs of T. serrulatus develop, whether by apomixis or automixis.
- ItemSomente MetadadadosKaryotype plasticity in crickets: Numerical, morphological, and nucleolar organizer region distribution pattern of Anurogryllus sp.(Univ Arizona, 2010-07-02) Schneider, Marielle Cristina [UNIFESP]; Zacaro, Adilson Ariza; Ferreira, Amilton; Cella, Doralice Maria; Universidade Federal de São Paulo (UNIFESP); Universidade Federal de Viçosa (UFV); Universidade de São Paulo (USP)Within the Orthopteran species, those of the suborder Ensifera have been rarely studied from the cytogenetic point of view, mainly due to the difficulties for taxonomic identification of its species. The Gryllidae is the second largest family of this suborder and possesses some genera, such as Anurogryllus, that occur only on the American continents. The aim of this work was to determine the karyotype characteristics, the meiotic chromosome behaviour, and the nucleolar organizer region (NOR) pattern of Anurogryllus sp (Orthoptera: Gryllidae). In the analyzed sample, high levels of numerical, morphological, and NORs polymorphisms were detected. Within five distinct karyotypes that were found, the basic karyotype of Anurogryllus sp. showed 2n(male) = 22 + X0 with acrocentric autosomes and a metacentric X sex chromosome; furthermore, a conspicuous secondary constriction related to the NOR was present along the entire short arm on pair 5. The other four types of karyotypes arose from centric fusions between elements of pairs 1/3, 2/6, 4/7 and a NOR partial translocation from pair 5 onto the long arm terminal region of one element of the fused pair 2/6. Such intraspecific variability and the consequences of high levels of polymorphism are discussed, leading to conjectures about the mechanisms that led to these chromosome rearrangements.
- ItemSomente MetadadadosMyelodysplastic syndrome in childhood: report of two cases with deletion of chromosome 4 and the Philadelphia chromosome(Elsevier B.V., 2002-06-01) Dalla Torre, Cristiane Arruda [UNIFESP]; Lee, MLD; Yoshimoto, Maysa; Lopes, Luis Fernando; Melo, L. N.; Toledo, Silvia Regina Caminada de [UNIFESP]; Andrade, Joyce Anderson Dufles [UNIFESP]; Universidade Federal de São Paulo (UNIFESP); Universidade de São Paulo (USP)We report two pediatric patients with unclassified myelodysplastic syndrome (MDS) by the French-American-British (FAB) group. Both cases had clinical and hematological peculiarities, which had not been described yet. the cytogenetic alterations were 4q deletion and the Philadelphia (Ph) chromosome which appeared at different moments of the disease. One patient showed the Ph chromosome at disease transformation and the other at diagnosis. the different breakpoints at 4q and the presence of Ph could be a marker of this form of MDS. the association of clinical and hematological findings suggests the possibility of a new group of pediatric MDS. (C) 2002 Elsevier B.V. All rights reserved.
- ItemSomente MetadadadosPadronização do teste de arranjos de polimorfismos de nucleotídeos únicos (SNPa) para a detecção de anormalidades genético-moleculares em leucemia mieloide aguda e síndromes mielodisplásicas(Universidade Federal de São Paulo (UNIFESP), 2014-09-26) Noronha, Thiago Rodrigo de [UNIFESP]; Chauffaille, Maria de Lourdes Lopes Ferrari Chauffaille [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)Introduction: Single nucleotide polymorphism array (SNPa) is a type of DNA microarray which is used to detect polymorphisms within a population. SNP is a variation of a single nucleotide in a DNA sequence, and is the most frequent type of variation in the genome. Millions of SNPs have been identified and a map of SNPs can be used as an excellent genotypic marker for research. SNPa has been widely used in cancer genetics due to its great performance in providing information of copy number variation (CNV) and copy neutral loss of heterozygosity (CN-LOH). In Onco-hematology, AML/MDS provide an interesting model for investigation of new molecular changes by SNPa with implications for pathogeneses of diseases. This is evidenced by the lack of cytogenetic abnormalities in cases of AML/MDS and general lack of molecular assays that can be used to detect such abnormalities. Objectives: The objectives of this study were to standardize the SNPa method in AML and MDS, and to establish the similarities and differences between SNPa and karyotype. Materials and Methods: 25 patients diagnosed with AML (n=22) and MDS (n = 3) were studied. The G-banding karyotype according to usual method and SNPa (Cytoscan HD - Affymetrix) were performed using DNA extracted from mononuclear cells from bone marrow (BM) and from buccal cells (BC). Results: The mean age of the patients studied was 54 years old, and the median age, 55 years (range from 28 – 93). 12 (48%) were male and 13 (52%) female. 10 patients showed abnormal karyotype (40,0%), 11 normal (44,0%) and 4 had no mitosis (16,0%). Regarding the BM SNPa: 17 were abnormal (68.0%) and 8 were normal (32.0%). Comparing the karyotype with SNPa from the 25 cases, by karyotype was possible to detect a total of 17 alterations (deletions/loss: 8, trissomy/gain: 7 and translocation: 2) and by SNPa a total of 42 alterations (loss: 17, gain: 16 and CN-LOH: 9). Conclusion: It was possible to standardize SNPa in AML/MDS and compare it with the abnormalities detected by karyotype. SNPa increased the detection rate of abnormalities compared to the karyotype. It was possible to confirm that it is a reliable and sensitive instrument for detecting submicroscopic and CN-LOH changes. SNPa also offered a new set of abnormalities that deserve to be further investigated in future studies.