The Experts below are selected from a list of 18321 Experts worldwide ranked by ideXlab platform

Maria Debiecrychter - One of the best experts on this subject based on the ideXlab platform.

  • endometrial stromal sarcoma with a sole t x 17 Chromosome Change report of a case and review of the literature
    Gynecologic Oncology, 2003
    Co-Authors: Frederic Amant, Philippe Moerman, Isabelle Cadron, Anne Hagemeijer, Ignace Vergote, Maria Debiecrychter
    Abstract:

    Abstract Background Endometrial stromal sarcomas (ESSs) exhibit varying degrees of malignancy and heterogeneity at the karyotypic level. The biological mechanisms that contribute to tumorigenesis of ESS are still largely unknown. Case A 33-year-old woman suffering from ESS was treated primarily surgically. Cytogenetic evaluation of the primary uterine nodule and metastatic tumor showed 46,XX,t(X;17)(p11:q23) karyotype in all metaphases analyzed. Normal endometrial cells exhibited 46,XX karyotype. Fluorescence in situ hybridization analysis confirmed the presence of the reciprocal t(X;17) translocation and allowed for the positioning of the Chromosome X breakpoint distal to SSX1 gene loci. Conclusion Our report of a previously undescribed sole cytogenetic translocation in an advanced stage of ESS might identify a cytogenetically distinct subgroup of ESS and help to reveal genes involved in ESS tumorigenesis.

  • specific Chromosome Change associated with acquisition in vivo of tumorigenicity in carcinogen induced rat urinary bladder carcinoma cells
    Genes Chromosomes and Cancer, 1991
    Co-Authors: Maria Debiecrychter, Masayuki Azuma, Kim Zukowski, Ryoichi Oyasu, Ching Y Wang
    Abstract:

    The correlation between chromosomal Changes and tumorigenic potential of rat bladder epithelial cells was investigated. Seven cell lines were established from neoplastic urothelial cells derived from heterotopically transplanted rat bladders treated with topical application of one of two carcinogens, N-methyl-N-nitrosourea (MNU) or N-hydroxy-N-glucuronosyl-2-aminofluorene. Loss of the short arm of Chromosome 3 was demonstrated in three of four lines tumorigenic in the nude mouse, but in none of three nontumorigenic lines. One of the three nontumorigenic cell lines (D44c) was treated further in vitro with MNU. All six tumorigenic, but none of the four nontumorigenic, morphologically altered cell lines derived from D44c demonstrated loss of the short arm of Chromosome 3. These results suggest that Chromosome 3 alterations may be associated with the tumorigenicity of carcinogen-induced rat bladder epithelial cells.

Herman Van Den Berghe - One of the best experts on this subject based on the ideXlab platform.

Jennifer Marshall A Graves - One of the best experts on this subject based on the ideXlab platform.

  • did sex Chromosome turnover promote divergence of the major mammal groups de novo sex Chromosomes and drastic rearrangements may have posed reproductive barriers between monotremes marsupials and placental mammals
    BioEssays, 2016
    Co-Authors: Jennifer Marshall A Graves
    Abstract:

    Comparative mapping and sequencing show that turnover of sex determining genes and Chromosomes, and sex Chromosome rearrangements, accompany speciation in many vertebrates. Here I review the evidence and propose that the evolution of therian mammals was precipitated by evolution of the male-determining SRY gene, defining a novel XY sex Chromosome pair, and interposing a reproductive barrier with the ancestral population of synapsid reptiles 190 million years ago (MYA). Divergence was reinforced by multiple translocations in monotreme sex Chromosomes, the first of which supplied a novel sex determining gene. A sex Chromosome-autosome fusion may have separated eutherians (placental mammals) from marsupials 160 MYA. Another burst of sex Chromosome Change and speciation is occurring in rodents, precipitated by the degradation of the Y. And although primates have a more stable Y Chromosome, it may be just a matter of time before the same fate overtakes our own lineage. Also watch the video abstract.

  • reversal and convergence in marsupial Chromosome evolution
    Cytogenetic and Genome Research, 2003
    Co-Authors: Willem Rens, Jennifer Marshall A Graves, P C M Obrien, Helen Fairclough, L Harman, Malcolm A Fergusonsmith
    Abstract:

    The karyotypes of marsupial species are characterized by their relatively low number of Chromosomes, and their conservation. Most species have diploid numbers lying between the two modes, 2n = 14 and 2n = 22, but the karyotype of Aepyprymnus rufescens is exceptional in containing 2n = 32 Chromosomes. Many differences in diploid number between marsupial species can be accounted for by particular fissions and fusions, which are easy to detect because of the low numbers of Chromosomes in each karyotype. This should be a system in which it is possible to detect reversals and repeated Chromosome rearrangements. We have used Chromosome-specific paints derived from A. rufescens to compare the karyotypes of eight marsupial species, representing closely and distantly related taxa, to trace Chromosome Change during evolution, and especially to detect reversals and convergence. From these and other painting comparisons, we conclude that there have been at least three reversals of fusions by fissions, and at least three fusions or fissions that have occurred independently in different lineages.

  • undermethylation associated with retroelement activation and Chromosome remodelling in an interspecific mammalian hybrid
    Nature, 1998
    Co-Authors: Rachel J Oneill, Michael J Oneill, Jennifer Marshall A Graves
    Abstract:

    Genetic models1,2 predict that genomic rearrangement in hybrids can facilitate reproductive isolation and the formation of new species by preventing gene flow between the parent species and hybrid (sunflowers are an example3). The mechanism underlying hybridization-induced Chromosome remodelling is as yet unknown, although mobile element activity has been shown to be involved in DNA rearrangement in some dysgenic Drosophila hybrids4,5. It has been proposed that DNA methylation evolved as a means of repressing the movement of mobile elements (the host defence model6,7). If such a protective mechanism were to fail, mobile elements could be activated, and could cause major and rapid genome alterations8,9. Here we demonstrate the occurrence of genome-wide undermethylation, retroviral element amplification and Chromosome remodelling in an interspecific mammalian hybrid (Macropus eugenii × Wallabia bicolor). Atypically extended centromeres of Macropus eugenii derived autosomes in the hybrid were composed primarily of an unmethylated, amplified retroviral element not detectable in either parent species. These results, taken with the observation of deficient methylation and de novo Chromosome Change in other mammalian hybrids, indicate that the failure of DNA methylation and subsequent mobile-element activity in hybrids could facilitate rapid karyotypic evolution.

Lynn Margulis - One of the best experts on this subject based on the ideXlab platform.

  • Symbiogenesis. A new principle of evolution rediscovery of Boris Mikhaylovich Kozo-Polyansky (1890–1957)
    Paleontological Journal, 2010
    Co-Authors: Lynn Margulis
    Abstract:

    The following is a heavily edited transcript of my illustrated lecture, that included our 14 minute video (with a 2 minute animation model) that shows each step in live organisms hypothesized in the origin of nucleated cells from bacteria (“eukaryosis”). New observations presented with modern examples of live phenomena make us virtually certain that B.M. Kozo-Polyansky’s “new principle” (1924) of the importance of symbiogenesis in the evolutionary process of at least 2000 million years of life on Earth is correct. The widely touted but undocumented explanation of the origin of evolutionary novelty by “gradual accumulation of random mutations” will be considered an erroneous early 20th century hunch proffered primarily by Englishmen, North Americans and other anglophones. They (Neodarwinist “explanations”) will be replaced by the details of symbiogenesis: genetic mergers especially speciation by genome acquisition, karyotypic fissions (neocentromere formation, related Chromosome Change) and D.I. Williamson’s larval transfer concept for animals. Although ignored and dismissed in his life time, Kozo-Polyansky’s brilliant work will be lauded for symbiogenesis in the same style that Gregor Mendel’s studies of inheritance of “factors” in peas was for recognition of his establishment of diploid organism genetic principles by the beginning of the 20th century. My talk, photographs and moving pictures were presented at the Darwin conference, St. Petersburg, on September 23, 2009 introduced by E. Kolchinsky.

  • symbiogenesis a new principle of evolution rediscovery of boris mikhaylovich kozo polyansky 1890 1957
    Paleontological Journal, 2010
    Co-Authors: Lynn Margulis
    Abstract:

    The following is a heavily edited transcript of my illustrated lecture, that included our 14 minute video (with a 2 minute animation model) that shows each step in live organisms hypothesized in the origin of nucleated cells from bacteria (“eukaryosis”). New observations presented with modern examples of live phenomena make us virtually certain that B.M. Kozo-Polyansky’s “new principle” (1924) of the importance of symbiogenesis in the evolutionary process of at least 2000 million years of life on Earth is correct. The widely touted but undocumented explanation of the origin of evolutionary novelty by “gradual accumulation of random mutations” will be considered an erroneous early 20th century hunch proffered primarily by Englishmen, North Americans and other anglophones. They (Neodarwinist “explanations”) will be replaced by the details of symbiogenesis: genetic mergers especially speciation by genome acquisition, karyotypic fissions (neocentromere formation, related Chromosome Change) and D.I. Williamson’s larval transfer concept for animals. Although ignored and dismissed in his life time, Kozo-Polyansky’s brilliant work will be lauded for symbiogenesis in the same style that Gregor Mendel’s studies of inheritance of “factors” in peas was for recognition of his establishment of diploid organism genetic principles by the beginning of the 20th century. My talk, photographs and moving pictures were presented at the Darwin conference, St. Petersburg, on September 23, 2009 introduced by E. Kolchinsky.

Emanuela Maserati - One of the best experts on this subject based on the ideXlab platform.

  • bone marrow failure may be caused by Chromosome anomalies exerting effects on runx1t1 gene
    Molecular Cytogenetics, 2018
    Co-Authors: Roberto Valli, Luciana Vinti, Annalisa Frattini, M Fabbri, Giuseppe Montalbano, Carla Olivieri, Antonella Minelli, Franco Locatelli, Francesco Pasquali, Emanuela Maserati
    Abstract:

    The majority of the cases of bone marrow failure syndromes/aplastic anaemias (BMFS/AA) are non-hereditary and considered idiopathic (80–85%). The peripheral blood picture is variable, with anaemia, neutropenia and/or thrombocytopenia, and the patients with idiopathic BMFS/AA may have a risk of transformation into a myelodysplastic syndrome (MDS) and/or an acute myeloid leukaemia (AML), as ascertained for all inherited BMFS. We already reported four patients with different forms of BMFS/AA with Chromosome anomalies as primary etiologic event: the Chromosome Changes exerted an effect on specific genes, namely RUNX1, MPL, and FLI1, leading to the disease. We report two further patients with non-hereditary BM failure, with diagnosis of severe aplastic anaemia and pancytopenia caused by two different constitutional structural anomalies involving Chromosome 8, and possibly leading to the disorder due to effects on the RUNX1T1 gene, which was hypo-expressed and hyper-expressed, respectively, in the two patients. The Chromosome Change was unbalanced in one patient, and balanced in the other one. We analyzed the sequence of events in the pathogenesis of the disease in the two patients, including a number of non-haematological signs present in the one with the unbalanced anomaly. We demonstrated that in these two patients the primary event causing BMFS/AA was the constitutional Chromosome anomaly. If we take into account the cohort of 219 patients with a similar diagnosis in whom we made cytogenetic studies in the years 2003–2017, we conclude that cytogenetic investigations were instrumental to reach a diagnosis in 52 of them. We postulate that a Chromosome Change is the primary cause of BMFS/AA in a not negligible proportion of cases, as it was ascertained in 6 of these patients.

  • new recurrent Chromosome Change in pediatric therapy related myelodysplastic syndrome unbalanced translocation 1 6 with cryptic duplication of short arm of Chromosome 6
    Leukemia & Lymphoma, 2012
    Co-Authors: Elisa Tassano, Roberto Valli, Francesco Pasquali, Emanuela Maserati, Elisa Tavella, Concetta Micalizzi, Cristina Cuoco, Cristina Morerio
    Abstract:

    The incidence of therapy-related myelodysplastic syndrome (t-MDS) in pediatric patients is increasing in parallel with the more successful management of the primary tumor, but scant information is available on clinical and cytogenetic characteristics. We report here two children affected by t-MDS after chemo/radiotherapy for a primary solid tumor, both with an unbalanced translocation 1/6 in their bone marrow. Characterization by array comparative genomic hybridization of the imbalances showed an almost identical pattern: almost complete trisomy of the long arm of Chromosome 1, and a terminal deletion and interstitial duplication of the short arm of Chromosome 6. The gain of Chromosome 6 short arm encompasses regions already highlighted as possibly relevant for t-MDS in adults, and we suggest that the unbalanced translocation reported here be considered a new recurrent, non-random chromosomal abnormality in pediatric patients with t-MDS.