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Results for “karyotype evolution”

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PubMed1997

Isolation of chromosome-specific paints from high-resolution flow karyotypes of the sheep (Ovis aries).

High-resolution bivariate flow karyotypes were obtained using fibroblast cell lines from a sheep with a normal karyotype (2n = 54), from sheep carrying Robertsonian translocation chromosomes and from sheep-hamster somatic cell hybrids. By taking advantage of the presence of chromosome polymorphisms, translocation chromosomes and sheep-hamster somatic cell hybrids, all sheep chromosomes were isolated by flow sorting. Chromosome-specific paints were generated from each sorted peak using degenerate oligonucleotide-primed polymerase chain reaction (DOP-PCR). The sheep chromosome present in each peak was identified by chromosome-specific microsatellite analysis of the DOP-PCR products and fluorescence in situ hybridization (FISH) onto DAPI-banded sheep metaphase chromosomes. The chromosome-specific DNA obtained in this study can be used for the production of genomic libraries and as a resource for mapping randomly cloned DNA sequences that will greatly aid the construction of genetic and physical maps in the sheep. The chromosome-specific paints will facilitate chromosome identification and contribute to the study of karyotype evolution in the sheep and related species.

Animals↗
PubMed2003

Chromosomal polymorphism of mandarin vole, Microtus mandarinus (Rodentia).

The mitotic and meiotic chromosomes of mandarin vole, Microtus mandarinus Milne-Edwards, from Shandong Province of China were analyzed by conventional, G- and C-banding and Silver-staining techniques. We detected chromosomal polymorphism in the vole, exhibiting diploid chromosome numbers 2n = 48-50 and variable morphology of the 1st pair, one medium sized telocentric pair and the X chromosomes. Four types of karyotypes were revealed in the population. According to banding analysis, there were pericentric inversion, Robertsonian fusion and translocation in M. mandarinus karyotype evolution. The X displayed two different morphologies, which could be explained by prericentric inversion and a telocentric autosome translocation.

Animals↗
PubMed1982

Characterization of a new chromosomal marker for acute lymphoblastic leukemia from a long-term cell line.

A bone marrow aspirate from a child with acute lymphoblastic leukemia (ALL) at first relapse was used to establish cell line # 697. The cultured line and marrow aspirates taken at initial diagnosis and first relapse were examined and compared. Similarities in all patterns evaluated confirmed the leukemic origin of the line. Morphologically, the cells were typically lymphoblastic. Cytochemically, they were slightly acid phosphatase-positive and negative for peroxidase, ASD chloroacetate esterase, and nonspecific esterase. Immunologically, they were found positive for common-ALL antigen (CALLA), Ia-associated antigen, terminal deoxynucleotidyl transferase (TdT), and cytoplasmic IgM (cIgM) and slightly positive for surface IgM (sIgM). Testing for Epstein-Barr virus (EBV) capsid antigen was also positive. Cytogenetic evaluations performed on initial, relapse, and cell line specimens each revealed the presence of a pseudodiploid cell line characterized by a consistent marker chromosome. GTG-, QFQ-, and RF-banding identified the marker as being derived from a translocation involving chromosomes #7 and #19: t(7;19) (q11;q13). Iso 7q, -5, -9, and +2 were also found in significant association with the marker and were viewed as demonstrating continued karyotypic evolution within the cell line. From these data, cell line #697 has been classified as a leukemic line of B-cell lineage in a transitional stage between pre-B and mature B cells.

B-Lymphocytes↗
PubMed1987

Philadelphia chromosome positive essential thrombocythemia evolving into lymphoid blast crisis.

The Philadelphia chromosome with the classic translocation t(9;22) was detected in all metaphases of a patient with essential thrombocythemia who presented without hematologic signs of chronic myeloid leukemia (CML). After 12 months of treatment with hydroxyurea followed by 6 months of busulfan, the disease transformed into lymphoid blast crisis with the immunophenotype of pre-pre-B cells frequently seen in lymphoid blast crisis of CML. This progression was not associated with karyotypic evolution because lymphoblasts contained only the Philadelphia chromosome. Further clinical course in this patient confirmed the development of a Philadelphia chromosome positive stem cell with predominantly megakaryocytic committment through partially megakaryocytic/lymphoid differentiation to purely lymphoid committment, a previously unreported transformation.

Adult↗
PubMed1990

The unbalanced 1;7 translocation in de novo myelodysplastic syndrome and its clinical implication.

In our chromosome study of 97 patients with myelodysplastic syndrome (MDS), six showed an unbalanced translocation between chromosomes 1 and 7 [-7, +der(1)t(1;7)(p11;p11)]. All of them had morphologic myelodysplasia in trilineage of bone marrow cells, and cytopenia was the major finding in the peripheral blood. All six patients had symptoms of infection at the time of diagnosis, and five showed immunologic abnormalities (polyclonal hypergammaglobulinemia in four and increased marrow plasma cells in three). None of the patients survived more than 11 months after the diagnosis; the median survival time was 4 months. Both of the two patients whose karyotypes were reexamined in the course of their disease showed karyotypic evolution accompanying the coincidental leukemic transformation. Six patients with MDS who had the same chromosome abnormality [t(1;7)] are described and their characteristic clinical features are presented.

Adolescent↗
PubMed2004

Human centromere repositioning "in progress".

Centromere repositioning provides a potentially powerful evolutionary force for reproductive isolation and speciation, but the underlying mechanisms remain ill-defined. An attractive model is through the simultaneous inactivation of a normal centromere and the formation of a new centromere at a hitherto noncentromeric chromosomal location with minimal detrimental effect. We report a two-generation family in which the centromeric activity of one chromosome 4 has been relocated to a euchromatic site at 4q21.3 through the epigenetic formation of a neocentromere in otherwise cytogenetically normal and mitotically stable karyotypes. Strong epigenetic inactivation of the original centromere is suggested by retention of 1.3 megabases of centromeric alpha-satellite DNA, absence of detectable molecular alteration in chromosome 4-centromereproximal p- and q-arm sequences, and failure of the inactive centromere to be reactivated through extensive culturing or treatment with histone deacetylase inhibitor trichostatin A. The neocentromere binds functionally essential centromere proteins (CENP-A, CENP-C, CENP-E, CENP-I, BUB1, and HP1), although a moderate reduction in CENP-A binding and sister-chromatid cohesion compared with the typical centromeres suggests possible underlying structural/functional differences. The stable mitotic and meiotic transmissibility of this pseudodicentric-neocentric chromosome in healthy individuals and the ability of the neocentric activity to form in a euchromatic site in preference to a preexisting alphoid domain provide direct evidence for an inherent mechanism of human centromere repositioning and karyotype evolution "in progress." We discuss the wider implication of such a mechanism for meiotic drive and the evolution of primate and other species.

Autoantigens↗
PubMed2000

Centromere cleavage is a mechanism underlying isochromosome formation in skin and head and neck carcinomas.

Centromeric rearrangements, in the form of isochromosomes or whole-arm translocations, are the most common recurrent changes in head and neck and skin carcinomas. Little is known about the mechanisms behind the origin of these chromosome rearrangements. In the present study, one basal cell carcinoma and two squamous cell carcinomas of the head and neck were thoroughly studied by cytogenetic and fluorescence in situ hybridization techniques. All tumors showed intratumor heterogeneity in the form of cytogenetically related subclones (in all tumors) and unrelated clones (in one tumor). Assessment of karyotypic evolution in these tumors suggests that centromeric cleavage is a mechanism giving rise to isochromosomes. A similar mechanism may also be involved in the formation of whole-arm translocations.

Basal Cell Carcinoma↗
PubMed1995

Double mutations of the N-ras gene in a patient with acute myelomonocytic leukemia.

We report a patient with acute myelomonocytic leukemia (AMMoL) who showed two independent point mutations of the N-ras gene at codons 12 and 13. Longitudinal analysis revealed that one mutation at codon 13 was detectable throughout his disease course and the other at codon 12 emerged as a second mutation 14 months after the diagnosis was made, at the refractory stage. Cloning to vector and subsequent sequencing confirmed that these mutations occurred in different alleles. Chromosome findings showed a simple abnormal karyotype at presentation and further karyotypic aberrations during his disease course, concomitantly with the second mutation of the N-ras gene. These findings revealed a close relationship among the disease progression, karyotypic evolution and a newly-appearing N-ras mutation.

Aclarubicin↗
PubMed1979

A hypodiploid clone and its duplicate in acute lymphoblastic leukemia.

Examination of the bone marrow of a 63-year-old man who had acute lymphoblastic leukemia revealed a population of cells with 32 chromosomes and another population with 64 chromosomes, the karyotypical exact duplicate of the first clone. The karyotypic evolution was studied and the findings compared with those described in two similar cases previously reported. It is postulated that severe hypodiploidy is associated with reduced capability of cellular survival, promoting a strong tendency for duplication.

Bone Marrow↗
PubMed1988

An acquired Robertsonian translocation dic(14;14)(p11;p11) in a patient with a myelodysplastic syndrome following treatment of multiple myeloma.

Acquired Robertsonian translocations are considered to be very rare chromosome changes in human malignancy, and only three cases have been described. We report a dic(14;14)(p11;p11) in a patient with myelodysplastic syndromes (MDS) following treatment for multiple myeloma. This patient also had other complex chromosomal abnormalities. The pattern of karyotype evolution in this patient was established by a series of cytogenetic studies. The relationship of the complex chromosomal changes to MDS following treatment for multiple myeloma is discussed.

Aged↗
PubMed2000

Transposition of duplicated chromosomal segment involving fused BCR-ABL gene or ABL oncogene alone in chronic myelocytic leukemia and Ph chromosome-positive acute leukemia with complex karyotypes.

Thirty-six patients with chronic myelocytic leukemia (CML) in the blastic phase were examined by fluorescence in situ hybridization to clarify the mechanisms of progression of the disease. Two of 19 CML patients in the blastic phase (10.5%) had an extra fused BCR-ABL gene on structurally complex chromosome aberrations in addition to the Ph chromosome. Another patient had an extra ABL oncogene on the end of a deleted chromosome, resulting in three copies of the ABL oncogene. These three patients showed additional chromosome aberrations, such as der(12), der(15), and der(18), which differ from the standard karyotypic evolution in the blastic phase. Amplification of the fused BCR-ABL gene or the ABL oncogene seemed to be induced by transposition. These segmental transpositions suggest that these regions have high genetic instability possibly leading to blastic transformation.

Chromosome Aberrations↗
PubMed1995

Chromosome banding in Amphibia. XXI. Inversion polymorphism and multiple nucleolus organizer regions in Agalychnis callidryas (Anura, Hylidae).

Cytogenetic analyses were performed on several populations of the Central American tree frog Agalychnis callidryas, using conventional methods and banding techniques. The karyotype of this species is distinguished by an inversion polymorphism in chromosome 9, which is either submetacentric or telocentric. The populations examined are in Hardy-Weinberg equilibrium with respect to the two alternative morphs of chromosome 9. This is the first report of the occurrence of an intrapopulational chromosomal inversion polymorphism in the order Anura. In male meiosis, the two chromosomes 9 form a bivalent exhibiting a ring-like pairing configuration with terminal chiasmata in both arms, regardless of whether the paired homologs are heteromorphic or homomorphic. Furthermore, individual specimens of A. callidryas exhibit one or two unexpected 18S + 28S ribosomal RNA gene clusters, in addition to the standard nucleolus organizers. The chromosomal localization of these extra nucleolus organizers is identical in all metaphases from the same specimen and shows a specific intraindividual pattern. The karyotype evolution in the phyllomedusine hylids, the structure of the various classes of heterochromatin, and the occurrence and possible origin of the rare inversion polymorphisms and multiple nucleolus organizers in A. callidryas and a few other amphibian species are discussed.

Animals↗
PubMed1989

A cytogenetic study of 53 human gliomas.

Cytogenetic studies were performed on human glioma samples obtained by stereotactic biopsy, stereotactic craniotomy, or routine craniotomy. Using in situ culture and robotic harvesting techniques, we obtained suitable metaphases in 50 (94%) of 53 tumors, including 28 diffuse astrocytomas, four juvenile pilocytic astrocytomas, two gliosarcomas, three other miscellaneous astrocytomas, eight oligodendrogliomas, four mixed oligodendroglioma-astrocytomas, and four ependymomas. Cytogenetic studies were performed only on primary cultures; the mean culture time was 9.6 days (range 1-31 days). One or more chromosomally abnormal clones were observed in 35 (66%) tumors. Eleven (21%) other specimens had random nonclonal chromosome abnormalities. In four (8%) specimens, no chromosome abnormalities were noted. The results of this study suggest that grade 3 and 4 tumors are more likely to contain an abnormal clone than tumors of grade 1 or 2 (p less than 0.01). The most common numeric chromosome abnormalities were -6, +7, -10, -13, -14, -15, -18, and -Y. The most common structural abnormalities involved 1p, 6q, 7q, 8p, 9p, 11p, 11q, 13q, and 19q. Four tumors had two or more independent clones and ten contained subclones demonstrating karyotype evolution. With in situ culture and robotic harvesting techniques, cytogenetic studies can be successful on nearly all human gliomas, including those derived from small stereotactic biopsies.

Adolescent↗
PubMed2001

Frequent mitotic errors in tumor cells of genetically micro-heterogeneous glioblastomas.

Glioblastoma multiforme (GBM) is characterized by intratumoral heterogeneity as to both histomorphology and genetic changes, displaying a wide variety of numerical chromosome aberrations the most common of which are monosomy 10 and trisomy 7. Moreover, GBM in vitro are known to have variable karyotypes within a given tumor cell culture leading to rapid karyotype evolution through a high incidence of secondary numerical chromosome aberrations. The aim of our study was to investigate to what extent this mitotic instability of glioblastoma cells is also present in vivo. We assessed the spatial distribution patterns of numerical chromosome aberrations in vivo in a series of 24 GBM using two-color in situ hybridization for chromosomes 7/10, 8/17, and 12/18 on consecutive 6-microm paraffin-embedded tissue slides. The chromosome aberration patterns were compared with the histomorphology of the investigated tumor assessed from a consecutive HE-stained section, and with the in vitro karyotype of cell cultures established from the tumors. All investigated chromosomes showed mitotic instability, i.e., numerical aberrations within significant amounts of tumor cells in a scattered distribution through the tumor tissue. As to chromosomes 10 and 17, only monosomy occurred, as to chromosome 7 only trisomy/polysomy, apparently as a result of selection in favor of the respective aberration. Conversely, chromosomes 8, 12, and 18 displayed scattered patterns of monosomy as well as trisomy within a given tumor reflecting a high mitotic error rate without selective effects. The karyotypes of the tumor cell cultures showed less variability of numerical aberrations apparently due to clonal adaptation to in vitro conditions. We conclude that glioblastoma cells in vivo are characterized by an extensive tendency to mitotic errors. The resulting clonal diversity of chromosomally aberrant cells may be an important biological constituent of the well-known ability of glioblastomas to preserve viable tumor cell clones under adaptive stress in vivo, in clinical terms to rapidly recur after antitumoral therapy including radio- or chemotherapy.

Adult↗
PubMed1998

A rare variant translocation t(3;8)(q29;q22) without AML1/ETO fusion transcript in a case of oligoblastic leukemia.

A 43-year-old man with oligoblastic leukemia and t(3;8) variant translocation is reported. At first he was classified as refractory anemia with excess of blasts in transformation according to the FAB criteria for myelodysplastic syndrome. Remission was obtained after intensive chemotherapy. After 8 months, a relapse occurred as overt M2 AML. At presentation chromosome study of bone marrow cells using R- and G-bandings revealed 45,X, -Y,t(3;8)(q29;q22) in 35 of the 42 metaphases analyzed and 46,XY,t(3;8) in one metaphase in addition to normal karyotype in the other six metaphases. However, RT-PCR assay showed no AML1/ETO fusion transcript. At relapse, a karyotype of 46, XY,t(3;8), deletion(4)(p14), add(7)(q32) was observed in all abnormal cells indicating a clonal karyotypic evolution. We believed that this case should be diagnosed as an early form of M2 AML initially. It may be the first case of oligoblastic leukemia with t(3;8) variant translocation. Further study is needed to elucidate its molecular entity.

Adult↗
PubMed1974

Non-random chromosome changes in human cancer.

Chromosome changes in human cancer cells appear to evolve by non-random losses and/or gains of particular homologues or groups. It is probable that some of the apparent losses or gains actually represent formation of new chromosome structures, which are then classified as markers or are misclassified as normal homologues. In many cancers these changes appear to continue at a high rate throughout the life of the cancer (so that in some cancers almost every cell will exhibit a different karyotype). In other cancers the rate of change may be slow or arrested so that all cells will have the same abnormal karyotype. One very common step in karyotype evolution is doubling of the entire chromosome complement (2n → 4n or more commonly, S → 2S where S is the stemline number). The 2S cells tend to replace the original stemline. Homologues which have larger amounts of concentrated blocks of heterochromatin (i.e. late replicating DNA) seem more apt to be lost.

Breast Neoplasms↗
PubMed1985

Unusual Ph translocations in CML: four new cases.

Four variants of the Ph chromosome translocation in chronic myelogenous leukemia (CML) patients are described. Two had an unusual simple translocation involving chromosomes #7 and #17. In two cases, the translocation, aside from involving #9 and #22, involved a third chromosome, chromosome #6 and chromosome #11, respectively. Three cases showed also karyotypic evolution during the blastic phase of the disease: in two cases, a new reciprocal translocation was found that involved a chromosome #9 at band q34. The clinical and cytogenetic significance of these results is briefly discussed.

Adolescent↗
PubMed1990

Synaptonemal complex analysis in Talpa occidentalis spermatocytes (Insectivora, Mammalia). II. Evolution of the X-chromosome self-pairing process.

Zygotene and pachytene configurations of the X chromosome were studied in whole-mount, silver-stained preparations of spermatocytes from XY males from a population of Talpa occidentalis in which sex reversal has been described. The most striking finding in this study was a self-pairing conformation of the axial (differential) element of the X chromosome. This self-pairing was markedly constant in the site of initiation, which invariably involved the distal free end of the X and the region beyond the X-Y pairing segment, so that X-Y synapsis was never disturbed. In addition, self-pairing occurred later than autosomal synapsis and was accompanied by thickening of the axes, although this seemed to occur after the formation of an ordinary synaptonemal complex. The etiology of this phenomenon may be based on residual homology, possibly due to conservation of a primitive isochromosome throughout the karyotypic evolution of this species. However, the possible relationship between self-pairing and sex reversal remains obscure.

Animals↗