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Journal articles on the topic 'Chromosome 6'
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1
Hausmann, Michael, C. Paul Popescu, Jeannine Boscher, Dominique Kerboœf, Jürgen Dölle, and Christoph Cremer. "Identification and Cytogenetic Analysis of an Abnormal Pig Chromosome for Flow Cytometry and Sorting." Zeitschrift für Naturforschung C 48, no. 7-8 (August 1, 1993): 645–53. http://dx.doi.org/10.1515/znc-1993-7-819.
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Abstract For cytogenetics of pig (Sus scrofa domestica) and the influence of chromosome aberrations on pig production, high interest exists in flow sorted chromosomes for gene mapping, to establish DNA-libraries, or to produce DNA-probes. Flow karyotyping and sorting as well as slit scan flow analysis of metaphase chromosomes of an abnormal cell type carrying a translocation marker chromosome 6/15 are described. Flow sorting of the largest chromosomes of these cells was performed. After sorting the chromosomes still had a well preserved morphology and were identified microscopically by G-banding. The quality of the band pattern of the sorted chromosomes was compatible to that of isolated chromosomes not subjected to flow cytometry. The sorted fraction showed an enrichment of chromosom e 6/15 and chromosome 1 which have quantitatively about the same integrated fluorescence intensity. Slit scan flow analysis was performed to discriminate these two chromosomes. Metacentric and submetacentric chromosom es were analyzed according to their bimodal slit scan profiles. Profiles of the largest chromosomes were distinguished by their different centromeric indices. Two groups were interpreted as the normal chromosome 1 and the translocation chromosom e 6/15.
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Fan, Haitao, Zhe Liu, Peng Zhan, and Guoliang Jia. "Pericentric inversion of chromosome 6 and male fertility problems." Open Medicine 17, no. 1 (January 1, 2022): 191–96. http://dx.doi.org/10.1515/med-2022-0411.
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Abstract As a significant chromosomal structural abnormality, chromosomal inversion is closely related to male infertility. For inversion carriers, the interchromosomal effect explains male infertility, but its specific mechanism remains unclear. Additionally, inversion carriers with different chromosomes have different clinical manifestations. Therefore, genetic counseling is difficult in clinical practice. Herein, four male carriers of pericentric inversion in chromosome 6 have been described. Two patients showed asthenospermia, one showed azoospermia, and the wife of the remaining patient had recurrent miscarriages. Through a literature search, the association between the breakpoint of pericentric inversion in chromosome 6 and male fertility problems are also discussed in this study. Overall, important genes related to asthenospermia in chromosome 6p21 were found, which may be related to the clinical phenotype. These results suggest that physicians should focus on the breakpoints of inversion in genetic counseling.
3
Ganguly, Bani Bandana, Vijay Kadam, and Nitin N. Kadam. "Clinical Expression of an Inherited Unbalanced Translocation in Chromosome 6." Case Reports in Genetics 2011 (2011): 1–6. http://dx.doi.org/10.1155/2011/396450.
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Unbalanced chromosomal rearrangements are not common; however, they have a significant clinical expression. The parental balanced translocation produces unbalanced chromosome, which is transmitted to next generation through fertilization of gametes carrying the derivative chromosome. The carriers of balanced rearrangements mostly do not have recognizable phenotypic expression. We report a family comprising of healthy and non-consanguineous young parents and their preemie newborn severely affected with congenital anomalies and systemic disorders. Conventional Gbanding analysis of somatic chromosomes identified a balanced translocation, t(6;10)(p23;q24), in mother and an unbalanced rearrangement, der(6)t(6:10)(p23;q24)mat, in the child. The child has inherited a derivative chromosome 6 with partial deletion of 6(p23-pter) and partial trisomy 10(q24-qter), which has resulted in fusion of genes of two different chromosomes. The prominent phenotypic features of del(6p), including high forehead, flat nasal bridge, agenesis of left ear, atrial septal defect (ASD), craniosynostosis, and growth retardation, are overlapping with specific Axenfeld-Reiger-, Larsen-, and Ritscher-Sinzel/3-C syndromes, however, lacking in ocular anomalies, skeletal laxity, or cerebellar malformation. Therefore, this paper rules out the isolated effect of del(6p23) or trisomy 10(q24) on distinct previously reported syndromes and proposes the combined effect of unbalanced chromosomal alteration.
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Mo, Kevin, Teagan Tran, Arjina Boodaghian, John Wear, John Ho, Clark Robin, and Mitchell Goldstein. "An Unbalanced Translocation Involving Partial Duplication of Chromosome 6 and Partial Deletion of Chromosome 10 in a Premature Infant with Tetralogy of Fallot." Neonatology Today 15, no. 9 (September 20, 2020): 20–25. http://dx.doi.org/10.51362/neonatology.today/202091592025.
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Purpose: To report a case of simultaneous chromosome 10 partial deletion and chromosome 6 partial duplication in a preterm infant. Methods: This is a retrospective case report followed with clinical observation, echocardiogram, and genetic testing. Results: A neonate with Tetralogy of Fallot, clubbed feet, low set ears, and webbed neck was found to have chromosomal abnormalities that are consistent with unbalanced translocation between chromosomes 6 and 10, resulting in a partial duplication of chromosome 6 and partial deletion of chromosome 10. Discussion: Chromosome microarray testing in a patient with multiple congenital anomalies can facilitate rapid diagnosis and treatment with the potential to improve the management of complications and subsequent development.
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Ogata, T., D. Ayusawa, M. Namba, E. Takahashi, M. Oshimura, and M. Oishi. "Chromosome 7 suppresses indefinite division of nontumorigenic immortalized human fibroblast cell lines KMST-6 and SUSM-1." Molecular and Cellular Biology 13, no. 10 (October 1993): 6036–43. http://dx.doi.org/10.1128/mcb.13.10.6036-6043.1993.
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Using nontumorigenic immortalized human cell lines KMST-6 (KMST) and SUSM-1 (SUSM), we attempted to identify the chromosome that carries a putative senescence-related gene(s). These cell lines are the only ones that have been established independently from normal human diploid fibroblasts following in vitro mutagenesis. We first examined restriction fragment length polymorphisms on each chromosome of these immortalized cell lines and their parental cell lines and found specific chromosomal alterations common to these cell lines (a loss of heterozygosity in KMST and a deletion in SUSM) on the long arm of chromosome 7. In addition to these, we also found that introduction of chromosome 7 into these cell lines by means of microcell fusion resulted in the cessation of cell division, giving rise to cells resembling cells in senescence. Introduction of other chromosomes, such as chromosomes 1 and 11, on which losses of heterozygosity were also detected in one of the cell lines (KMST), to either KMST or SUSM cells or of chromosome 7 to several tumor-derived cell lines had no effect on their division potential. These results strongly suggest that a gene(s) affecting limited-division potential or senescence of normal human fibroblasts is located on chromosome 7, probably at the long arm of the chromosome, representing the first case in which a specific chromosome reverses the immortal phenotype of otherwise normal human cell lines.
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Ogata, T., D. Ayusawa, M. Namba, E. Takahashi, M. Oshimura, and M. Oishi. "Chromosome 7 suppresses indefinite division of nontumorigenic immortalized human fibroblast cell lines KMST-6 and SUSM-1." Molecular and Cellular Biology 13, no. 10 (October 1993): 6036–43. http://dx.doi.org/10.1128/mcb.13.10.6036.
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Using nontumorigenic immortalized human cell lines KMST-6 (KMST) and SUSM-1 (SUSM), we attempted to identify the chromosome that carries a putative senescence-related gene(s). These cell lines are the only ones that have been established independently from normal human diploid fibroblasts following in vitro mutagenesis. We first examined restriction fragment length polymorphisms on each chromosome of these immortalized cell lines and their parental cell lines and found specific chromosomal alterations common to these cell lines (a loss of heterozygosity in KMST and a deletion in SUSM) on the long arm of chromosome 7. In addition to these, we also found that introduction of chromosome 7 into these cell lines by means of microcell fusion resulted in the cessation of cell division, giving rise to cells resembling cells in senescence. Introduction of other chromosomes, such as chromosomes 1 and 11, on which losses of heterozygosity were also detected in one of the cell lines (KMST), to either KMST or SUSM cells or of chromosome 7 to several tumor-derived cell lines had no effect on their division potential. These results strongly suggest that a gene(s) affecting limited-division potential or senescence of normal human fibroblasts is located on chromosome 7, probably at the long arm of the chromosome, representing the first case in which a specific chromosome reverses the immortal phenotype of otherwise normal human cell lines.
7
Gecheff, K., T. Hvarleva, S. Georgiev, T. Wilkes, and A. Karp. "Cytological and molecular evidence of deletion of ribosomal RNA genes in chromosome 6 of barley (Hordeum vulgare)." Genome 37, no. 3 (June 1, 1994): 419–25. http://dx.doi.org/10.1139/g94-059.
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The barley chromosomal mutant T-35, in which only one pair of satellite chromosomes is apparent, was analyzed using a range of cytological and molecular techniques. Using conventional Feulgen staining, Giemsa and silver banding, in situ hybridization, and Southern blot analysis, unequivocal cytological and molecular evidence was obtained that T-35 is a homozygous deletion of rRNA genes residing in the nucleolus organizer region (NOR) of chromosome 6. According to the criteria of arm ratio and Giemsa-banding pattern of this chromosome, the deletion involved the whole NOR, one of the breakpoints being localized in the short arm proximally to the NOR-associated heterochromatic band, the other probably in the satellite of the chromosome. As a result of this deletion, an increased activity of the rRNA genes (as indicated by the size of the silver bands) on the other NOR-bearing chromosome (chromosome 7) was observed. The possible reasons for this phenomenon are discussed.Key words: barley, nucleolar organizing region, deletion, silver and Giemsa banding, in situ hybridization.
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Atli, Emine Ikbal, Hakan Gurkan, Engin Atli, Ulfet Vatansever, Betul Acunas, and Cisem Mail. "De Novo Subtelomeric 6p25.3 Deletion with Duplication of 6q23.3-q27: Genotype–Phenotype Correlation." Journal of Pediatric Genetics 09, no. 01 (August 12, 2019): 032–39. http://dx.doi.org/10.1055/s-0039-1694703.
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AbstractDuplications of 6q and deletions of 6p have been reported in more than 30 cases of live born infants and given rise to widespread abnormalities recognizable as a specific clinical syndrome. Different phenotypes have been described with variable clinical signs. Most cases involve the coexistence of unbalanced translocations affecting one or the other of the chromosomes. However, duplication of both chromosome 6q and deletion of 6p regions have been reported in only a few cases. Here, we report the first duplication of chromosome band 6q23.3–q27 with deletion of 6p25.3. This is the first case in the literature involving changes to these specific chromosomal regions; a medium size duplication of the distal long arm and smaller deletion of the terminal short arm of chromosome 6. In the literature, there are no other cases where these two specific chromosomal aberrations are observed together. Conventional chromosome analysis was performed to investigate the patient. Chromosome structure was identified using fluorescence in situ hybridization for subtelomeric regions of chromosome 6 and array comparative genomic hybridization analysis (array-CGH).
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Mahesh, G., N. B. Ramachandra, and H. A. Ranganath. "Autoradiographic study of transcription and dosage compensation in the sex and neo-sex chromosome of Drosophila nasuta nasuta and Drosophila nasuta albomicans." Genome 44, no. 1 (February 1, 2001): 71–78. http://dx.doi.org/10.1139/g00-100.
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Cellular autoradiography is used to study the transcription patterns of the polytene X chromosomes in Drosophila nasuta nasuta and D. n. albomicans. D. n. nasuta, with 2n = 8, includes a pair of complete heteromorphic sex chromosomes, whereas D. n. albomicans, with 2n = 6, has a pair of metacentric neo-sex chromosomes representing incomplete heteromorphic sex chromosomes. The neo-X chromosome has two euchromatic arms, one representing the ancestral X while the other represents the ancestral autosome 3 chromosomes. The metacentric neo-Y chromosome has one arm with a complete heterochromatic ancestral Y and the other arm with a euchromatic ancestral autosome 3. The transcription study has revealed that the X chromosome in D. n. nasuta is hyperactive, suggesting complete dosage compensation, while in the neo-X chromosome of D. n. albomicans the ancestral X chromosome is hyperactive and the ancestral autosome 3, which is part of the neo-sex chromosome, is similar to any other autosomes. This finding shows dosage compensation on one arm (XLx/) of the neo-X chromosome, while the other arm (XR3/YR3) is not dosage compensated and has yet to acquire the dosage compensatory mechanism.Key words: Drosophila, chromosomal races, neo-sex chromosome, transcription and dosage compensation.
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Miyashita, Naohiko, Cathy C. Laurie-Ahlberg, Alan N. Wilton, and Ted H. Emigh. "QUANTITATIVE ANALYSIS OF X CHROMOSOME EFFECTS ON THE ACTIVITIES OF THE GLUCOSE 6-PHOSPHATE AND 6-PHOSPHOGLUCONATE DEHYDROGENASES OF DROSOPHILA MELANOGASTER." Genetics 113, no. 2 (June 1, 1986): 321–35. http://dx.doi.org/10.1093/genetics/113.2.321.
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ABSTRACT By combining 20 X chromosomes with five autosomal backgrounds, the relative importance of these factors with respect to the activity variations of G6PD and 6PGD in Drosophila melanogaster were investigated. Analysis of variance revealed that there exist significant X chromosome, autosomal background and genetic interaction effects. The effect of the X chromosome was due mainly to the two allozymic forms of each enzyme, but some within-allozyme effects were also detected. From the estimated variance components, it was concluded that the variation attributed to the autosomal background is much larger than the variation attributed to the X chromosome, even when the effect of the allozymes is included. The segregation of the allozymes seems to account for about 10% of the total activity variation of each enzyme. The variation due to the interaction between the X chromosome and the autosomal background is much smaller than variations attributed either to the X chromosome or to the autosomal background. The interaction effect is indicated by the change of the ranking of the X chromosomes for different autosomal backgrounds. Highly significant and positive correlation between G6PD and 6PGD activities was detected. Again, the contribution of the autosomal background to the correlation was much larger than that attributed to the X chromosome.
11
Pérez-Simón, J. A., R. Garcı́a-Sanz, M. D. Tabernero, J. Almeida, M. González, J. Fernández-Calvo, M. J. Moro, J. M. Hernández, J. F. San Miguel, and A. Orfão. "Prognostic Value of Numerical Chromosome Aberrations in Multiple Myeloma: A FISH Analysis of 15 Different Chromosomes." Blood 91, no. 9 (May 1, 1998): 3366–71. http://dx.doi.org/10.1182/blood.v91.9.3366.3366_3366_3371.
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Recent observations indicate that chromosome aberrations are important prognostic factors in patients with multiple myeloma (MM) treated with high-dose chemotherapy. Nevertheless, the inherent problems of conventional cytogenetics have hampered the systematic evaluation of this parameter in series of patients treated with conventional chemotherapy. Fluorescence in situ hybridization (FISH) analysis is an attractive alternative for evaluation of numerical chromosomal changes. In the present study, we analyze the relationship between aneuploidies of 15 different chromosomes assessed by FISH and prognosis in a series of 63 patients with MM treated with conventional chemotherapy. After a median follow-up of 61 months (range, 6 to 109), 49% of patients are still alive with a median survival of 33 months. The overall incidence of numerical chromosome abnormalities was 70%. This incidence significantly increased when seven or more chromosomes were analyzed (53 patients), reaching 81%. Trisomies of chromosomes 6, 9, and 17 were associated with prolonged survival (P = .033, P = .035, and P = .026, respectively); by contrast, overall survival (OS) was lower in cases with monosomy 13 (as assessed by deletion of Rb gene,P = .0012). From the clinical point of view, loss of Rb gene was associated with a poor performance status; low hemoglobin levels; high creatinine, C-reactive protein, and lactic dehydrogenase serum levels; high percentage of bone marrow plasma cells (BMPC); extensive bone lytic lesions; and advanced clinical stage. Other chromosome abnormalities such as trisomy of chromosome 9 and 17 were associated with good prognostic features including high hemoglobin levels, early clinical stage, β2microglobulin less than 6 μg/mL, and low percentage of BMPC. A multivariate analysis for OS showed that S-phase PC greater than 3% (P = .010) and β2microglobulin serum levels greater than 6 μg/mL (P = .024), together with monosomy of chromosome 13 (P = .031) and nontrisomy of chromosome 6 (P = .048) was the best combination of independent parameters for predicting survival in patients with MM. According to these results, chromosomal analysis is of great use in patients with MM at diagnosis to have a correct prognostic evaluation for clinical decision making.
12
Gaeta, Robert T., Tatiana V. Danilova, Changzeng Zhao, Rick E. Masonbrink, Morgan E. McCaw, and James A. Birchler. "Recovery of a telomere-truncated chromosome via a compensating translocation in maize." Genome 54, no. 3 (March 2011): 184–95. http://dx.doi.org/10.1139/g10-108.
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Maize-engineered minichromosomes are easily recovered from telomere-truncated B chromosomes but are rarely recovered from A chromosomes. B chromosomes lack known genes, and their truncation products are tolerated and transmitted during meiosis. In contrast, deficiency gametes resulting from truncated A chromosomes prevent their transmission. We report here a de novo compensating translocation that permitted recovery of a large truncation of chromosome 1 in maize. The truncation (trunc-1) and translocation with chromosome 6 (super-6) occurred during telomere-mediated truncation experiments and were characterized using single-gene fluorescent in situ hybridization (FISH) probes. The truncation contained a transgene signal near the end of the broken chromosome and transmitted together with the compensating translocation as a heterozygote to approximately 41%–55% of progeny. Transmission as an addition chromosome occurred in ~15% of progeny. Neither chromosome transmitted through pollen. Transgene expression (Bar) cosegregated with trunc-1 transcriptionally and phenotypically. Meiosis in T1 plants revealed eight bivalents and one tetravalent chain composed of chromosome 1, trunc-1, chromosome 6, and super-6 in diplotene and diakinesis. Our data suggest that de novo compensating translocations allow recovery of truncated A chromosomes by compensating deficiency in female gametes and by affecting chromosome pairing and segregation. The truncated chromosome can be maintained as an extra chromosome or together with the super-6 as a heterozygote.
13
Pirkova, A. V., and L. V. Ladygina. "Mutagenic impact of the biotoxin of veined rapa whelk Rapana venosa (Valenciennes, 1846) (Gastropoda, Muricidae)." Ruthenica, Russian Malacological Journal 30, no. 1 (February 11, 2020): 45–53. http://dx.doi.org/10.35885/ruthenica.2021.30(1).6.
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The invasion of the predatory gastropod mollusk Rapana venosa, known as veined rapa whelk, in the Black Sea and its outspread in many regions of the World Ocean have led to complex structural changes in the communities of bivalve mollusks. When capturing a prey, the adult rapa whelk excretes a biotoxin from the hypobranchial gland that causes severe paralysis of the musculature of bivalve mollusks. Under experimental conditions, it was established that the biotoxin, after the short-term exposure of the fertilized eggs of the mussels Mytilus galloprovincialis to it, has a mutagenic effect, causing chromosomal aberrations in the embryos. The acentric groups of chromosomes, single and multiple chromosome bridges, chromosome lags and polyploidy indicate transformation or destruction of threads of the achromatin spindle in the mitosis anaphase. The chromosome fragmentation and emergence of ring chromosomes in the metaphase and anaphase of mitosis of mussel embryos are the consequence of the partial destruction of chromatin. The underdeveloped shell, anomalous development of D-veligers’ velum, and the changed form of the ‘eye spots’ and hepatopancreas of the larvae at the veliconcha stage result from chromosomal mutations during the embryo development. The mechanism of the rapa whelk biotoxin action on the chromosomal apparatus of mussel embryos is discussed.
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Moore, Karen J., and Rosemary W. Elliott. "Mouse chromosome 6." Mammalian Genome 4, S1 (1993): S88—S109. http://dx.doi.org/10.1007/bf00360832.
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Nurnberger, J. I., and T. Foroud. "Chromosome 6 workshop." Psychiatric Genetics 8, no. 2 (1998): 79–84. http://dx.doi.org/10.1097/00041444-199800820-00010.
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Elliott, Rosemary W., and Karen J. Moore. "Mouse Chromosome 6." Mammalian Genome 3, S1 (1992): S81—S103. http://dx.doi.org/10.1007/bf00648424.
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Elliott, Rosemary W., and Karen J. Moore. "Mouse chromosome 6." Mammalian Genome 7, S1 (January 1997): S100—S120. http://dx.doi.org/10.1007/s003359900318.
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Elliott, Rosemary W., and Karen J. Moore. "Mouse chromosome 6." Mammalian Genome 8, S1 (December 1998): S114—S135. http://dx.doi.org/10.1007/s003359900651.
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Elliott, Rosemary W., and Karen J. Moore. "Mouse Chromosome 6." Mammalian Genome 10, no. 10 (October 1, 1999): 945–46. http://dx.doi.org/10.1007/s003359901125.
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Eldridge, M. D. B., P. G. Johnston, R. L. Close, and P. S. Lowry. "Chromosomal rearrangements in rock wallabies, Petrogale (Marsupialia: Macropodidae). II. G-banding analysis of Petrogale godmani." Genome 32, no. 6 (December 1, 1989): 935–40. http://dx.doi.org/10.1139/g89-534.
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Chromosomal rearrangements in the two currently recognised races of Petrogale godmani were examined using C- and G-banding. The nominate race P. godmani godmani (2n = 20) was found to possess an inverted chromosome 5 and an acrocentric 6–10 fusion, which can be derived from a 6–10 centric fusion by a centromeric transposition. The Cape York race (2n = 22) was found to retain the ancestral submetacentric chromosome 4 and the ancestral chromosome 5. Thus despite their genie similarity, the two races clearly have major chromosomal differences and should be regarded as separate species. Petrogale g. godmani shares two derived chromosomes with another Queensland taxon, the assimilis race of P. assimilis, indicating recent common ancestry. The Cape York race retains characteristics of an ancestral stock of Petrogale and its genic similarity with P. g. godmani could therefore be the result of extensive introgression.Key words: chromosomal rearrangements, G-banding, Marsupialia, Petrogale.
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Anjos, Allison, Gabriela C. Rocha, Andressa Paladini, Tatiane C. Mariguela, and Diogo C. Cabral-de-Mello. "Karyotypes and Repetitive DNA Evolution in Six Species of the Genus Mahanarva (Auchenorrhyncha: Cercopidae)." Cytogenetic and Genome Research 149, no. 4 (2016): 321–27. http://dx.doi.org/10.1159/000450730.
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Insects of the Cercopidae family are widely distributed and comprise 59 genera and 431 species in the New World. They are xylemophagous, causing losses in agricultural and pasture grasses, and are considered as emerging pests. Chromosomally, these insects have been studied by standard techniques, revealing variable diploid numbers and primarily X0 sex chromosome systems (males). We performed chromosome studies in 6 Mahanarva (Cercopidae) species using standard and differential chromosome staining as well as mapping of repetitive DNAs. Moreover, the relationship between the repetitive DNAs was analyzed at the interspecific level. A diploid chromosome number of 2n = 19,X0 was documented, with chromosomes gradually decreasing in size. Neutral or GC-rich regions were detected which varied depending on the species. Fluorescence in situ hybridization with a (TTAGG)n telomeric motif probe revealed terminal signals, matching those of the Cot DNAs obtained from each species, that were also restricted to the terminal regions of all chromosomes. Dot blot analysis with the Cot fraction from M. quadripunctata showed that at least part of the repetitive genome is shared among the 6 species. Our data highlight the conservation of chromosomal features and organization of repetitive DNAs in the genus Mahanarva, suggesting a low differentiation for chromosomes and repetitive DNAs in most of the 6 species studied.
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Ayoub Bhatti, Arshad, and Manvi Khajuria. "Karyotypic and Morphometric Analysis of A Predatory Rove Beetle, Paederus littoralis (Coleoptera: Staphylinidae) from Jammu Region of Outer Himalayas, India." Biosciences, Biotechnology Research Asia 15, no. 2 (June 28, 2018): 495–99. http://dx.doi.org/10.13005/bbra/2654.
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In the present study, the chromosomes of a predatory rove beetle Paederus littoralis were studied from Jammu region of outer Himalayas. These beetles are also potential bio-control agents in suppressing the populations of cereal aphids. The diploid chromosome number was found to be 2n=32 including 22 metacentric, 3 submetacentric, 6 subtelocentric and 1 telocentric chromosomes. The sex chromosomes (Xyp) included submetacentric X and telocentric y chromosome. Meiotic observations comprised diplotene, diakinesis and metaphase-I. The study is helpful in solving taxonomic problems with in the family Staphylinidae and it authenticates the existence of this particular species through chromosomal data.
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Pérez-Simón, J. A., R. Garcı́a-Sanz, M. D. Tabernero, J. Almeida, M. González, J. Fernández-Calvo, M. J. Moro, J. M. Hernández, J. F. San Miguel, and A. Orfão. "Prognostic Value of Numerical Chromosome Aberrations in Multiple Myeloma: A FISH Analysis of 15 Different Chromosomes." Blood 91, no. 9 (May 1, 1998): 3366–71. http://dx.doi.org/10.1182/blood.v91.9.3366.
Full textAbstract:
Abstract Recent observations indicate that chromosome aberrations are important prognostic factors in patients with multiple myeloma (MM) treated with high-dose chemotherapy. Nevertheless, the inherent problems of conventional cytogenetics have hampered the systematic evaluation of this parameter in series of patients treated with conventional chemotherapy. Fluorescence in situ hybridization (FISH) analysis is an attractive alternative for evaluation of numerical chromosomal changes. In the present study, we analyze the relationship between aneuploidies of 15 different chromosomes assessed by FISH and prognosis in a series of 63 patients with MM treated with conventional chemotherapy. After a median follow-up of 61 months (range, 6 to 109), 49% of patients are still alive with a median survival of 33 months. The overall incidence of numerical chromosome abnormalities was 70%. This incidence significantly increased when seven or more chromosomes were analyzed (53 patients), reaching 81%. Trisomies of chromosomes 6, 9, and 17 were associated with prolonged survival (P = .033, P = .035, and P = .026, respectively); by contrast, overall survival (OS) was lower in cases with monosomy 13 (as assessed by deletion of Rb gene,P = .0012). From the clinical point of view, loss of Rb gene was associated with a poor performance status; low hemoglobin levels; high creatinine, C-reactive protein, and lactic dehydrogenase serum levels; high percentage of bone marrow plasma cells (BMPC); extensive bone lytic lesions; and advanced clinical stage. Other chromosome abnormalities such as trisomy of chromosome 9 and 17 were associated with good prognostic features including high hemoglobin levels, early clinical stage, β2microglobulin less than 6 μg/mL, and low percentage of BMPC. A multivariate analysis for OS showed that S-phase PC greater than 3% (P = .010) and β2microglobulin serum levels greater than 6 μg/mL (P = .024), together with monosomy of chromosome 13 (P = .031) and nontrisomy of chromosome 6 (P = .048) was the best combination of independent parameters for predicting survival in patients with MM. According to these results, chromosomal analysis is of great use in patients with MM at diagnosis to have a correct prognostic evaluation for clinical decision making.
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Kameoka, Daisuke, Alexander Lezhava, Hiroyuki Zenitani, Keiichiro Hiratsu, Makoto Kawamoto, Kohei Goshi, Kuninobu Inada, Hidenori Shinkawa, and Haruyasu Kinashi. "Analysis of Fusion Junctions of Circularized Chromosomes in Streptomyces griseus." Journal of Bacteriology 181, no. 18 (September 15, 1999): 5711–17. http://dx.doi.org/10.1128/jb.181.18.5711-5717.1999.
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ABSTRACT A filamentous soil bacterium, Streptomyces griseus2247, carries a 7.8-Mb linear chromosome. We previously showed by macrorestriction analysis that mutagenic treatments easily caused deletions at both ends of its linear chromosome and changed the chromosome to a circular form. In this study, we confirmed chromosomal circularization by cloning and sequencing the junction fragments from two deletion mutants, 404-23 and N2. The junction sequences were compared with the corresponding right and left deletion end sequences in the parent strain, 2247. No homology and a 6-bp microhomology were found between the two deletion ends of the 404-23 and N2 mutants, respectively, which indicate that the chromosomal circularization was caused by illegitimate recombination without concomitant amplification. The circularized chromosomes were stably maintained in both mutants. Therefore, the chromosomal circularization might have occurred to prevent lethal deletions, which otherwise would progress into the indispensable central regions of the chromosome.
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Kartapradja, Hannie, Nanis Sacharina Marzuki, Mark D. Pertile, David Francis, Lita Putri Suciati, Helena Woro Anggaratri, Debby Dwi Ambarwati, et al. "Exceptional Complex Chromosomal Rearrangements in Three Generations." Case Reports in Genetics 2015 (2015): 1–5. http://dx.doi.org/10.1155/2015/321014.
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We report an exceptional complex chromosomal rearrangement (CCR) found in three individuals in a family that involves 4 chromosomes with 5 breakpoints. The CCR was ascertained in a phenotypically abnormal newborn with additional chromosomal material on the short arm of chromosome 4. Maternal karyotyping indicated that the mother carried an apparently balanced CCR involving chromosomes 4, 6, 11, and 18. Maternal transmission of the derivative chromosome 4 resulted in partial trisomy for chromosomes 6q and 18q and a partial monosomy of chromosome 4p in the proband. Further family studies found that the maternal grandmother carried the same apparently balanced CCR as the proband’s mother, which was confirmed using the whole chromosome painting (WCP) FISH. High resolution whole genome microarray analysis of DNA from the proband’s mother found no evidence for copy number imbalance in the vicinity of the CCR translocation breakpoints, or elsewhere in the genome, providing evidence that the mother’s and grandmother’s CCRs were balanced at a molecular level. This structural rearrangement can be categorized as an exceptional CCR due to its complexity and is a rare example of an exceptional CCR being transmitted in balanced and/or unbalanced form across three generations.
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Li, J., D. L. Klindworth, F. Shireen, X. Cai, J. Hu, and S. S. Xu. "Molecular characterization and chromosome-specific TRAP-marker development for Langdon durum D-genome disomic substitution lines." Genome 49, no. 12 (December 2006): 1545–54. http://dx.doi.org/10.1139/g06-114.
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The aneuploid stocks of durum wheat ( Triticum turgidum L. subsp. durum (Desf.) Husnot) and common wheat ( T. aestivum L.) have been developed mainly in ‘Langdon’ (LDN) and ‘Chinese Spring’ (CS) cultivars, respectively. The LDN-CS D-genome chromosome disomic substitution (LDN-DS) lines, where a pair of CS D-genome chromosomes substitute for a corresponding homoeologous A- or B-genome chromosome pair of LDN, have been widely used to determine the chromosomal locations of genes in tetraploid wheat. The LDN-DS lines were originally developed by crossing CS nulli-tetrasomics with LDN, followed by 6 backcrosses with LDN. They have subsequently been improved with 5 additional backcrosses with LDN. The objectives of this study were to characterize a set of the 14 most recent LDN-DS lines and to develop chromosome-specific markers, using the newly developed TRAP (target region amplification polymorphism)-marker technique. A total of 307 polymorphic DNA fragments were amplified from LDN and CS, and 302 of them were assigned to individual chromosomes. Most of the markers (95.5%) were present on a single chromosome as chromosome-specific markers, but 4.5% of the markers mapped to 2 or more chromosomes. The number of markers per chromosome varied, from a low of 10 (chromosomes 1A and 6D) to a high of 24 (chromosome 3A). There was an average of 16.6, 16.6, and 15.9 markers per chromosome assigned to the A-, B-, and D-genome chromosomes, respectively, suggesting that TRAP markers were detected at a nearly equal frequency on the 3 genomes. A comparison of the source of the expressed sequence tags (ESTs), used to derive the fixed primers, with the chromosomal location of markers revealed that 15.5% of the TRAP markers were located on the same chromosomes as the ESTs used to generate the fixed primers. A fixed primer designed from an EST mapped on a chromosome or a homoeologous group amplified at least 1 fragment specific to that chromosome or group, suggesting that the fixed primers might generate markers from target regions. TRAP-marker analysis verified the retention of at least 13 pairs of A- or B-genome chromosomes from LDN and 1 pair of D-genome chromosomes from CS in each of the LDN-DS lines. The chromosome-specific markers developed in this study provide an identity for each of the chromosomes, and they will facilitate molecular and genetic characterization of the individual chromosomes, including genetic mapping and gene identification.
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Eldridge, M. D. B., and P. G. Johnston. "Chromosomal rearrangements in rock wallabies, Petrogale (Marsupialia: Macropodidae). VIII. An investigation of the nonrandom nature of karyotypic change." Genome 36, no. 3 (June 1, 1993): 524–34. http://dx.doi.org/10.1139/g93-072.
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Although the nonrandom nature of many chromosome breaks is well known, few studies have investigated the potential significance of this breakage specificity in chromosome evolution. The macropod genus Petrogale is an ideal group in which to investigate this phenomenon, since it comprises a large number of chromosomal forms, many of which appear to have differentiated relatively recently. By exposing Petrogale cells to mutagenic agents it should be possible to compare the distribution and abundance of induced breaks with those that are known to have occurred in vivo during the chromosomal differentiation of the genus. In this study, breaks were induced in mitotic chromosomes from P. assimilis and P. mareeba by exposing synchronized cultured fibroblasts to low doses of gamma radiation. The results were remarkably similar for both species and the distribution of breaks among the chromosomes appeared to be nonrandom. It was found that chromosomes 5, 6, and (possibly) 10 had a substantially higher rate of breakage than expected. These are also the chromosomes that occur disproportionately among the rearrangements identified in Petrogale. While the distribution of breaks along the chromosome appeared uniform or normal for most chromosomes, a putative "hot spot" was identified near the centromere in chromosome 5 of P. mareeba and in a homologous position near the telomere of chromosome 5 in P. assimilis. In a further experiment, a 1- to 2-h pulse of mitomycin C was used to induce centric fusions in cultured fibroblasts of P. penicillata (2n = 22); 2408 cells were examined and 112 fusions were identified. While it was found that all chromosomes participated in forming fusions, chromosome 10 was found to be most frequently involved, being present in 28.6% of the identifed fusions. This frequency is far greater than would be expected if fusions were to occur at random (10%). It is significant then that chromosome 10 has been involved in five of the eight centric fusions that have been identified in Petrogale and that it is also the chromosome that has been most frequently rearranged in Petrogale. These results suggest that features of the karyotype may influence the distribution and frequency of chromosome breaks and therefore the rate and nature of chromosome evolution.Key words: Petrogale, chromosome evolution, irradiation, induced rearrangements, mitomycin C.
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Gasser, Susan M. "Chromosome Structure: Coiling up chromosomes." Current Biology 5, no. 4 (April 1995): 357–60. http://dx.doi.org/10.1016/s0960-9822(95)00071-6.
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Nasiri, F., F. Mahjoubi, F. Manouchehry, F. Razazian, F. Mortezapour, and M. Rahnama. "Cytogenetic Findings in Mentally Retarded Iranian Patients." Balkan Journal of Medical Genetics 15, no. 2 (December 1, 2012): 29–34. http://dx.doi.org/10.2478/bjmg-2013-0004.
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ABSTRACT We conducted a cytogenetic study on 865 individuals with idiopathic mental retardation (MR) who were admitted to the Cytogenetics Department of the Iran Blood Transfusion Organisation (IBTO) Research Centre, Tehran, Iran; these were performed on blood samples using conventional staining methods. Chromosome anomalies were identified in 205 of the patients (23.6%). The majority were Down’s syndrome cases (n = 138). In 33 males, a positive fragile X anomaly was found .The remainder (n = 34) had other chromosomal abnormalities including structural chromosome aberrations (n = 23), marker chromosomes with an unknown origin (n = 3), sex chromosome aneuploidy (n = 6) and trisomy 18 (n = 2). The contribution of chromosome aberrations to the cause of MR in this group of patients is discussed.
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Sanamyan, M. F., and Sh U. Bobokhujaev. "Analysis of pollen fertility in aneuploid hybrids with substitutions for specific chromosomes or their arms in cotton G.hirsutum L." Biomics 12, no. 3 (2020): 376–79. http://dx.doi.org/10.31301/2221-6197.bmcs.2020-26.
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Analysis of pollen fertility in interspecific aneuploid F1 hybrids with substitutions of specific chromosomes (2, 4, 6, 7, 18) and chromosome arms (telo 6, telo11) of the cotton genome G. hirsutum L. revealed a decrease in fertility in all hybrid plants. It was shown that hybrid monosomics for chromosome 2 were characterized by a slight decrease in pollen fertility; hybrid monosomics of different families with substitution on chromosome 4 and on chromosome 6 - a significant decrease; hybrid monosomics with substitution on chromosome 7 and 18, as well as monotelodisome hybrid plants with substitution of an individual arm of chromosome 6 or 11 - a strong decrease, which indicated the existence of specific differences in pollen fertility in hybrid monosomic plants with substitution of specific chromosomes of the cotton genome due to the formation of partially unbalanced haplo-deficient gametes.
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Daibata, Masanori, Takahiro Taguchi, Yuiko Nemoto, Hirokuni Taguchi, and Isao Miyoshi. "Inheritance of Chromosomally Integrated Human Herpesvirus 6 DNA." Blood 94, no. 5 (September 1, 1999): 1545–49. http://dx.doi.org/10.1182/blood.v94.5.1545.
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Abstract Human herpesvirus 6 (HHV-6) genome has been detected in several human lymphoproliferative disorders with no signs of active viral infection, and found to be integrated into chromosomes in some cases. We previously reported a woman with HHV-6–infected Burkitt’s lymphoma. Fluorescence in situ hybridization showed that the viral genome was integrated into the long arm of chromosome 22 (22q13). The patient’s asymptomatic husband also carried HHV-6 DNA integrated at chromosome locus 1q44. To assess the possibility of chromosomal transmission of HHV-6 DNA, we looked for HHV-6 DNA in the peripheral blood of their daughter. She had HHV-6 DNA on both chromosomes 22q13 and 1q44, identical to the site of viral integration of her mother and father, respectively. The findings suggested that her viral genomes were inherited chromosomally from both parents. The 3 family members were all seropositive for HHV-6, but showed no serological signs of active infection. To confirm the presence of HHV-6 DNA sequences, we performed polymerase chain reaction (PCR) with 7 distinct primer pairs that target different regions of HHV-6. The viral sequences were consistently detected by single-step PCR in all 3 family members. We propose a novel latent form for HHV-6, in which integrated viral genome can be chromosomally transmitted. The possible role of the chromosomally integrated HHV-6 in the pathogenesis of lymphoproliferative diseases remains to be explained.
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Daibata, Masanori, Takahiro Taguchi, Yuiko Nemoto, Hirokuni Taguchi, and Isao Miyoshi. "Inheritance of Chromosomally Integrated Human Herpesvirus 6 DNA." Blood 94, no. 5 (September 1, 1999): 1545–49. http://dx.doi.org/10.1182/blood.v94.5.1545.417a25_1545_1549.
Full textAbstract:
Human herpesvirus 6 (HHV-6) genome has been detected in several human lymphoproliferative disorders with no signs of active viral infection, and found to be integrated into chromosomes in some cases. We previously reported a woman with HHV-6–infected Burkitt’s lymphoma. Fluorescence in situ hybridization showed that the viral genome was integrated into the long arm of chromosome 22 (22q13). The patient’s asymptomatic husband also carried HHV-6 DNA integrated at chromosome locus 1q44. To assess the possibility of chromosomal transmission of HHV-6 DNA, we looked for HHV-6 DNA in the peripheral blood of their daughter. She had HHV-6 DNA on both chromosomes 22q13 and 1q44, identical to the site of viral integration of her mother and father, respectively. The findings suggested that her viral genomes were inherited chromosomally from both parents. The 3 family members were all seropositive for HHV-6, but showed no serological signs of active infection. To confirm the presence of HHV-6 DNA sequences, we performed polymerase chain reaction (PCR) with 7 distinct primer pairs that target different regions of HHV-6. The viral sequences were consistently detected by single-step PCR in all 3 family members. We propose a novel latent form for HHV-6, in which integrated viral genome can be chromosomally transmitted. The possible role of the chromosomally integrated HHV-6 in the pathogenesis of lymphoproliferative diseases remains to be explained.
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Yen, Jui-Hung, Shao-Yin Chu, Yann-Jang Chen, Yi-Chieh Su, Chun-Ching Chien, Chun-Ying Weng, and Pei-Yi Chen. "A Maternally Inherited Rare Case with Chromoanagenesis-Related Complex Chromosomal Rearrangements and De Novo Microdeletions." Diagnostics 12, no. 8 (August 5, 2022): 1900. http://dx.doi.org/10.3390/diagnostics12081900.
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Chromoanagenesis is a phenomenon of highly complex rearrangements involving the massive genomic shattering and reconstitution of chromosomes that has had a great impact on cancer biology and congenital anomalies. Complex chromosomal rearrangements (CCRs) are structural alterations involving three or more chromosomal breakpoints between at least two chromosomes. Here, we present a 3-year-old boy exhibiting multiple congenital malformations and developmental delay. The cytogenetic analysis found a highly complex CCR inherited from the mother involving four chromosomes and five breakpoints due to forming four derivative chromosomes (2, 3, 6 and 11). FISH analysis identified an ultrarare derivative chromosome 11 containing three parts that connected the 11q telomere to partial 6q and 3q fragments. We postulate that this derivative chromosome 11 is associated with chromoanagenesis-like phenomena by which DNA repair can result in a cooccurrence of inter-chromosomal translocations. Additionally, chromosome microarray studies revealed that the child has one subtle maternal-inherited deletion at 6p12.1 and two de novo deletions at 6q14.1 and 6q16.1~6q16.3. Here, we present a familial CCR case with rare rearranged chromosomal structures and the use of multiple molecular techniques to delineate these genomic alterations. We suggest that chromoanagenesis may be a possible mechanism involved in the repair and reconstitution of these rearrangements with evidence for increasing genomic imbalances such as additional deletions in this case.
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Boroń, Alicja, Anna Grabowska, Aneta Spóz, and Anna Przybył. "B Chromosomes and Cytogenetic Characteristics of the Common Nase Chondrostoma nasus (Linnaeus, 1758)." Genes 11, no. 11 (November 6, 2020): 1317. http://dx.doi.org/10.3390/genes11111317.
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Supernumerary B chromosomes (Bs) are very promising structures, among others, in that they are an additional genomic compartment for evolution. In this study, we tested the presence and frequency of B chromosomes and performed the first cytogenetic examination of the common nase (Chondrostoma nasus). We investigated the individuals from two populations in the Vistula River basin, in Poland, according to the chromosomal distribution of the C-bands and silver nucleolar organizer regions (Ag-NORs), using sequential staining with AgNO3 and chromomycin A3 (CMA3). Furthermore, we analyzed the chromosomal localization of two rDNA families (45S and 5S rDNA) using fluorescence in situ hybridization (FISH) with rDNA probes. Chondrostoma nasus individuals showed a standard (A) chromosome set consisting of 2n = 50: 12 metacentric, 32 submetacentric, and 6 acrocentric chromosomes (NF = 94). Fourteen out of the 20 analyzed individuals showed 1–2 mitotically unstable submetacentric B chromosomes of different sizes. Six of them, in 14.1% of the analyzed metaphase plates, had a single, medium-sized submetacentric B (Bsm) chromosome (2n = 51) with a heterochromatic block located in its pericentromeric region. The other seven individuals possessed a Bsm (2n = 51) in 19.4% of the analyzed metaphase plates, and a second Bsm chromosome (2n = 52), the smallest in the set, in 15.5% of metaphase plates, whereas one female was characterized by both Bsm chromosomes (2n = 52) in 14.3% of the analyzed metaphase plates. AgNORs, GC-rich DNA sites, and 28S rDNA hybridization sites were observed in the short arms of two submetacentric chromosome pairs of A set. The constitutive heterochromatin was visible as C bands in the centromeric regions of almost all Chondrostoma nasus chromosomes and in the pericentromeric region of several chromosome pairs. Two 5S rDNA hybridization sites in the pericentromeric position of the largest acrocentric chromosome pair were observed, whereas two other such sites in co-localization on a smaller pair of NOR chromosomes indicate a species-specific character. The results herein broaden our knowledge in the field of B chromosome distribution and molecular cytogenetics of Chondrostoma nasus: a freshwater species from the Leuciscidae family.
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Solé-Soler, Roger, and Jordi Torres-Rosell. "Smc5/6, an atypical SMC complex with two RING-type subunits." Biochemical Society Transactions 48, no. 5 (September 23, 2020): 2159–71. http://dx.doi.org/10.1042/bst20200389.
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The Smc5/6 complex plays essential roles in chromosome segregation and repair, by promoting disjunction of sister chromatids. The core of the complex is constituted by an heterodimer of Structural Maintenance of Chromosomes (SMC) proteins that use ATP hydrolysis to dynamically associate with and organize chromosomes. In addition, the Smc5/6 complex contains six non-SMC subunits. Remarkably, and differently to other SMC complexes, the Nse1 and Nse2 subunits contain RING-type domains typically found in E3 ligases, pointing to the capacity to regulate other proteins and complexes through ubiquitin-like modifiers. Nse2 codes for a C-terminal SP-RING domain with SUMO ligase activity, assisting Smc5/6 functions in chromosome segregation through sumoylation of several chromosome-associated proteins. Nse1 codes for a C-terminal NH-RING domain and, although it has been proposed to have ubiquitin ligase activity, no Smc5/6-dependent ubiquitylation target has been described to date. Here, we review the function of the two RING domains of the Smc5/6 complex in the broader context of SMC complexes as global chromosome organizers of the genome.
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Haglund, U., G. Juliusson, B. Stellan, and G. Gahrton. "Hairy cell leukemia is characterized by clonal chromosome abnormalities clustered to specific regions." Blood 83, no. 9 (May 1, 1994): 2637–45. http://dx.doi.org/10.1182/blood.v83.9.2637.2637.
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Abstract Cytogenetic analysis was performed on B-cell mitogen-stimulated cells from 36 patients with symptomatic hairy cell leukemia. Evaluable metaphases were achieved from 30 patients, and (67%) showed clonal abnormalities. Recurrent chromosomal aberrations involving chromosomes 1, 2, 5, 6, 11, 19, and 20 were found. The abnormalities were mostly deletions and inversions, whereas translocations and numerical abnormalities, except trisomy 5, were rare. Fourteen patients showed multiple clones, which mostly were unrelated and found in different combinations in individual cells. Cells with non-clonal abnormalities identical to those found in clonal changes in other patients were common. Chromosome 5 was involved in clonal aberrations in 12 of 30 (40%) patients, most commonly as trisomy 5 (n = 4), or pericentric inversions (n = 6) and interstitial deletions (n = 4) involving band 5q13. Three patients showed two and 1 patient three different clones that involved chromosome 5. In addition, 1 patient had a rare constitutional inversion of chromosome 5 with breakpoints at p13.1 and q13.3. Pericentric inversions and interstitial deletions of chromosome 2 occurred clonally in 4 patients (13%) and in single cells of another 6 patients. Deletions of chromosome 1 at band q42 was found in 5 patients, and 1 patient had a translocation between 1q42 and a supernumerary chromosome 5. Deletions of 6q and 11q were similar to those commonly found in other lymphoproliferative disorders. Trisomy 5, structural abnormalities involving the pericentromeric regions of chromosomes 5 and 2, and 1q42 abnormalities were findings distinguishing the karyotypes in hairy cell leukemia from those of other hematologic malignancies.
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Haglund, U., G. Juliusson, B. Stellan, and G. Gahrton. "Hairy cell leukemia is characterized by clonal chromosome abnormalities clustered to specific regions." Blood 83, no. 9 (May 1, 1994): 2637–45. http://dx.doi.org/10.1182/blood.v83.9.2637.bloodjournal8392637.
Full textAbstract:
Cytogenetic analysis was performed on B-cell mitogen-stimulated cells from 36 patients with symptomatic hairy cell leukemia. Evaluable metaphases were achieved from 30 patients, and (67%) showed clonal abnormalities. Recurrent chromosomal aberrations involving chromosomes 1, 2, 5, 6, 11, 19, and 20 were found. The abnormalities were mostly deletions and inversions, whereas translocations and numerical abnormalities, except trisomy 5, were rare. Fourteen patients showed multiple clones, which mostly were unrelated and found in different combinations in individual cells. Cells with non-clonal abnormalities identical to those found in clonal changes in other patients were common. Chromosome 5 was involved in clonal aberrations in 12 of 30 (40%) patients, most commonly as trisomy 5 (n = 4), or pericentric inversions (n = 6) and interstitial deletions (n = 4) involving band 5q13. Three patients showed two and 1 patient three different clones that involved chromosome 5. In addition, 1 patient had a rare constitutional inversion of chromosome 5 with breakpoints at p13.1 and q13.3. Pericentric inversions and interstitial deletions of chromosome 2 occurred clonally in 4 patients (13%) and in single cells of another 6 patients. Deletions of chromosome 1 at band q42 was found in 5 patients, and 1 patient had a translocation between 1q42 and a supernumerary chromosome 5. Deletions of 6q and 11q were similar to those commonly found in other lymphoproliferative disorders. Trisomy 5, structural abnormalities involving the pericentromeric regions of chromosomes 5 and 2, and 1q42 abnormalities were findings distinguishing the karyotypes in hairy cell leukemia from those of other hematologic malignancies.
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Mariotto, Sandra, Liano Centofante, Carlos S. Miyazawa, Luiz Antonio Carlos Bertollo, and Orlando Moreira Filho. "Chromosome polymorphism in Ancistrus cuiabae Knaack, 1999 (Siluriformes: Loricariidae: Ancistrini)." Neotropical Ichthyology 7, no. 4 (2009): 595–600. http://dx.doi.org/10.1590/s1679-62252009000400006.
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Cytogenetic and FISH analyses were performed in 30 Ancistrus cuiabae specimens from a bay near the town of Poconé, in the Pantanal of Mato Grosso, Brazil. The observed diploid number was 2n = 34 chromosomes for both sexes and three distinct katyotypic formulae were found, namely cytotype A (20m, 8sm, 6st, Fundamental Number/FN = 68; 6 males and 11 females), cytotype B (19m, 8sm, 6st, 1a, FN = 67; 8 males and 4 females) and cytotype C (18m, 8sm, 6st, 2a, FN = 66; a single male). NORs's analyses showed that these regions were located in distinct sites on the NOR-bearing chromosome pair, according to cytotypes. Thus, in cytotype A, NORs were located in the terminal region of the short arm of the second metacentric chromosome pair; in cytotype B, they were detected in the short arm of the metacentric chromosome and interstitially on the acrocentric chromosome and, in cytotype C, NORs were observed in the interstitial region of the acrocentric chromosome pair. C-positive heterochromatic bands were adjacent to the rDNA sites in the corresponding chromosomes. Thus, the chromosomal polymorphism of A. cuiabae was probably originated through a pericentric inversion in chromosome pair nº 2 involving the NOR sites, which represents a novelty in the Ancistrini tribe. The results also broaden the knowledge of the chromosomal evolution in Ancistrus, the most derived genus of the Ancistrini tribe.
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Grutzner, F., A. Casey, and T. Daish. "105. MEIOTIC ACROBATS: MONOTREME SEX CHROMOSOME ORGANISATION DURING SPERMATOGENESIS." Reproduction, Fertility and Development 22, no. 9 (2010): 23. http://dx.doi.org/10.1071/srb10abs105.
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Monotremes feature an extraordinarily complex sex chromosome system which shares extensive homology with bird sex chromosomes but no homology to sex chromosomes of other mammals (1,2,3). At meiotic prophase I the ten sex chromosomes in platypus (nine in echidna) assemble in a sex chromosome chain. We previously identified the multiple sex chromosomes in platypus and echidna that form the meiotic chain in males (1,2,4). We showed that sex chromosomes assembly in the chain in a specific order (5) and that they segregate alternately (1). In secondary spermatocytes we observed clustering of X and Y chromosomes in sperm (6). Our current research investigates the formation of the synaptonemal complex, recombination and meiotic silencing of monotreme sex chromosomes. Meiotic sex chromosome inactivation (MSCI) has been observed in eutherian mammals, marsupials and birds but has so far not been investigated experimentally in monotremes. We found that during pachytene the X5Y5 end of the chain closely associates with the nucleolus and accumulates repressive chromatin marks (e.g. histone variant mH2A). In contrast to the differential accumulation of mH2A we observe extensive loading of the cohesin SMC3 on sex chromosomes in particular during the pachytene stage of meiotic prophase I. We have also used markers of active transcription and gene expression analysis to investigate gene activity in platypus meiotic cells. I will discuss how these findings contribute to our current understanding of the meiotic organisation of monotreme sex chromosomes and the evolution of MSCI in birds and mammals. (1) Grützner et al. (2004), Nature 432: 913–917.(2) Rens et al. (2007), Genome Biology 16;8(11): R243.(3) Veyrunes et al. (2008), Genome Research, 18(6): 995–1004.(4) Rens et al. (2004), Proceedings of the National Academy of Sciences USA. 101 (46): 16 257–16 261.(5) Daish et al. (2009), Reprod Fertil Dev. 21(8): 976–84.(6) Tsend-Ayush et al. (2009), Chromosoma 118(1): 53–69.
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Ziegler, Andreas. "Biology of Chromosome 6." DNA Sequence 8, no. 3 (January 1997): 189–201. http://dx.doi.org/10.3109/10425179709034072.
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Nurnberger, J. I., T. Foroud, G. Eckstein, J. Ekelund, S. Faraone, D. Goldman, T. Hinrichs, H. G. Hwu, J. Kelsoe, and M. Owen. "Chromosome 6 workshop report." American Journal of Medical Genetics 88, no. 3 (June 18, 1999): 233–38. http://dx.doi.org/10.1002/(sici)1096-8628(19990618)88:3<233::aid-ajmg5>3.0.co;2-b.
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Alleva, Benjamin, Nathan Balukoff, Amy Peiper, and Sarit Smolikove. "Regulating chromosomal movement by the cochaperone FKB-6 ensures timely pairing and synapsis." Journal of Cell Biology 216, no. 2 (January 11, 2017): 393–408. http://dx.doi.org/10.1083/jcb.201606126.
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In meiotic prophase I, homologous chromosome pairing is promoted through chromosome movement mediated by nuclear envelope proteins, microtubules, and dynein. After proper homologue pairing has been established, the synaptonemal complex (SC) assembles along the paired homologues, stabilizing their interaction and allowing for crossing over to occur. Previous studies have shown that perturbing chromosome movement leads to pairing defects and SC polycomplex formation. We show that FKB-6 plays a role in SC assembly and is required for timely pairing and proper double-strand break repair kinetics. FKB-6 localizes outside the nucleus, and in its absence, the microtubule network is altered. FKB-6 is required for proper movement of dynein, increasing resting time between movements. Attenuating chromosomal movement in fkb-6 mutants partially restores the defects in synapsis, in agreement with FKB-6 acting by decreasing chromosomal movement. Therefore, we suggest that FKB-6 plays a role in regulating dynein movement by preventing excess chromosome movement, which is essential for proper SC assembly and homologous chromosome pairing.
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White, R. A., S. V. Angeloni, and L. M. Pasztor. "Chromosomal localization of the ?-adducin gene to mouse Chromosome 6 and human Chromosome 2." Mammalian Genome 6, no. 10 (October 1995): 741–43. http://dx.doi.org/10.1007/bf00354298.
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Gokhman, Vladimir E. "Chromosomes of parasitic wasps of the superfamily Chalcidoidea (Hymenoptera): An overview." Comparative Cytogenetics 14, no. 3 (August 25, 2020): 399–416. http://dx.doi.org/10.3897/compcytogen.v14i3.56535.
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An overview of the current knowledge of chromosome sets of the parasitoid superfamily Chalcidoidea is given. Karyotypes of approximately 240 members of this group, i.e. just above one percent of described species, are studied up to now. Techniques for obtaining and analyzing preparations of chalcid chromosomes are outlined, including the so-called “traditional” and “modern” methods of differential staining as well as fluorescence in situ hybridization (FISH). Among the Chalcidoidea, the haploid chromosome number can vary from n = 3 to n = 11, with a clear mode at n = 6 and a second local maximum at n = 10. In this group, most chromosomes are either metacentric or submetacentric, but acrocentrics and/or subtelocentrics also can predominate, especially within karyotypes of certain Chalcidoidea with higher chromosome numbers. The following main types of chromosomal mutations are characteristic of chalcid karyotypes: inversions, fusions, translocations, polyploidy, aneuploidy and B chromosome variation. Although karyotype evolution of this superfamily was mainly studied using phylogenetic reconstructions based on morphological and/or molecular characters, chromosomal synapomorphies of certain groups were also revealed. Taxonomic implications of karyotypic features of the Chalcidoidea are apparently the most important at the species level, especially among cryptic taxa.
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Xu, Jie, and K. J. Kasha. "Identification of a barley chromosomal interchange using N-banding and in situ hybridization techniques." Genome 35, no. 3 (June 1, 1992): 392–97. http://dx.doi.org/10.1139/g92-059.
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The combination of N-banding and in situ hybridization was used to illustrate the rapid identification of the chromosomes involved in a newly formed chromosomal interchange (reciprocal translocation) in barley. The plant heterozygous for the interchange was derived from the backcross of 'Su Pie', a two-rowed Chinese winter barley cultivar (2n = 2x = 14), with pollen from a triploid interspecific F1 hybrid (2n = 3x = 21) obtained from the cross of 'Su Pie' × tetraploid Hordeum bulbosum accession GBC141 (2n = 4x = 28). Pollen mother cells of the interchanged plant exhibited one quadrivalent and five bivalents in 97.8% of cells. Partial sterility of florets was observed in spikes obtained from self-pollination and the plants morphologically resembled barley. Barley chromosomes were readily identified by N-banding from root-tip cells with one band missing from the short arm of one of the pair of chromosome 4. N-banding of metaphase I of meiosis revealed that chromosomes 1, 2, and 5 were not involved in the interchange. In situ hybridization with a rDNA probe showed that chromosomes 6 and 7 were paired as bivalents. In conclusion, chromosomes 3 and 4 are involved in the interchange with the breakpoint in the short arm of chromosome 4 between the two proximal N-bands. The use of chromosome-specific DNA probes for chromosome identification using in situ hybridization is proposed.Key words: barley, chromosomal interchange, N-banding, in situ hybridization, rDNA.
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Linde-Laursen, Ib, and Roland von Bothmer. "Orderly arrangement of the chromosomes within barley genomes of chromosome-eliminating Hordeum lechleri × barley hybrids." Genome 42, no. 2 (April 1, 1999): 225–36. http://dx.doi.org/10.1139/g98-158.
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One-hundred and nineteen progeny plants of crosses between one Hordeum lechleri (2n = 6x = 42) accession and the barley varieties 'Wong' and 'Igri' comprised 54 euploids (2n = 28), 8 hyperploids (2n = 29), 46 hypoploids (2n = 22 - 27), and 11 polyhaploids (2n = 21). Giemsa C-banding showed most interplant chromosome variation to be caused by elimination or, more seldom, duplication of barley chromosomes. The chromosomes of 'Wong' were preferentially lost in the order, 1H-4H-5H-3H-7H-2H-6H (5-4-7-3-1-2-6); those of 'Igri' in the order, 1H-3H or 6H-7H or 5H or 4H-2H (5-3 or 6-1 or 7 or 4-2), indicating different patterns of elimination. Over years chromosome elimination may be continuous. Hypoploid genomes of 'Wong' had the chromosomes arranged in the order, 1H-5H-2H-6H-7H-3H-4H (5-7-2-6-1-3-4), with a discontinuity between chromosomes 1H(5) and 4H(4); whereas in 'Igri' the order was (1H)-5H-2H-4H-7H-6H-3H-(1H) ((5)-7-2-4-1-6-3-(5)) with a discontinuity at 1H(5), indicating varietal differences. The patterns of barley chromosome elimination may be derived from chromosome orders. Elimination starts with a chromosome at the discontinuity, continues with the chromosome at the other end of the order, and proceeds more or less alternately towards the middle. In hybrids including 'Wong', duplication affected the two chromosomes situated at either end of barley chromosome order. A few older hybrids with 2n = 21 had three or four H.lechleri chromosomes substituted for as many barley chromosomes suggesting homoeology. Our observations support the hypothesis of an orderly arrangement of the chromosomes within genomes (Bennett 1981), but they do not agree with the idea of one 'natural karyotype' for each species (Bennett 1984b).Key words: Hordeum, interspecific hybrids, C-banding, chromosome elimination, chromosome order.
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Palecek, Jan. "SMC5/6: Multifunctional Player in Replication." Genes 10, no. 1 (December 22, 2018): 7. http://dx.doi.org/10.3390/genes10010007.
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The genome replication process is challenged at many levels. Replication must proceed through different problematic sites and obstacles, some of which can pause or even reverse the replication fork (RF). In addition, replication of DNA within chromosomes must deal with their topological constraints and spatial organization. One of the most important factors organizing DNA into higher-order structures are Structural Maintenance of Chromosome (SMC) complexes. In prokaryotes, SMC complexes ensure proper chromosomal partitioning during replication. In eukaryotes, cohesin and SMC5/6 complexes assist in replication. Interestingly, the SMC5/6 complexes seem to be involved in replication in many ways. They stabilize stalled RFs, restrain RF regression, participate in the restart of collapsed RFs, and buffer topological constraints during RF progression. In this (mini) review, I present an overview of these replication-related functions of SMC5/6.
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De Sanctis, G. T., J. B. Singer, A. Jiao, C. N. Yandava, Y. H. Lee, T. C. Haynes, E. S. Lander, D. R. Beier, and J. M. Drazen. "Quantitative trait locus mapping of airway responsiveness to chromosomes 6 and 7 in inbred mice." American Journal of Physiology-Lung Cellular and Molecular Physiology 277, no. 6 (December 1, 1999): L1118—L1123. http://dx.doi.org/10.1152/ajplung.1999.277.6.l1118.
Full textAbstract:
Quantitative trait locus (QTL) mapping was used to identify chromosomal regions contributing to airway hyperresponsiveness in mice. Airway responsiveness to methacholine was measured in A/J and C3H/HeJ parental strains as well as in progeny derived from crosses between these strains. QTL mapping of backcross [(A/J × C3H/HeJ) × C3H/HeJ] progeny ( n = 137–227 informative mice for markers tested) revealed two significant linkages to loci on chromosomes 6 and 7. The QTL on chromosome 6 confirms the previous report by others of a linkage in this region in the same genetic backgrounds; the second QTL, on chromosome 7, represents a novel locus. In addition, we obtained suggestive evidence for linkage (logarithm of odds ratio = 1.7) on chromosome 17, which lies in the same region previously identified in a cross between A/J and C57BL/6J mice. Airway responsiveness in a cross between A/J and C3H/HeJ mice is under the control of at least two major genetic loci, with evidence for a third locus that has been previously implicated in an A/J and C57BL/6J cross; this indicates that multiple genetic factors control the expression of this phenotype.
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Liu, Guangxin, Yue Lan, Haoyang Xin, Fengrong Hu, Zhuhua Wu, Jisen Shi, and Mengli Xi. "Cytogenetic Analysis of Lilium rosthornii." Journal of the American Society for Horticultural Science 141, no. 5 (September 2016): 444–48. http://dx.doi.org/10.21273/jashs03757-16.
Full textAbstract:
Lily (Lilium L.) species produce among the most important cut flowers worldwide. China has ≈55 species of Lilium. Although many plants from this genus have been used in hybridization efforts, their cytology has remained unclear. The goal of the current study was to characterize the chromosomes of Lilium rosthornii Diels. Root tips were used to characterize Giemsa C-banding, propidium iodide (PI) banding, and 45S rDNA locations. The karyotype of L. rosthornii belongs to type 3B. C-banding revealed polymorphic banding patterns with the following formula: 2n = 24 = CI = 4C + 14CI+ + 2I+ +2I+ 2. Two of the four 45S rDNA hybridization sites were located at pericentromeric positions on the two short arms of the homologues of chromosome 1, and the other two were located on the long arms of one chromosome 6 homolog and one chromosome 11 homolog. Six of the eight PI bands were detected in the centromeres of the homologues of chromosomes 1, 5, and 8, and the other two PI bands were detected on the long arms of one chromosome 6 and one chromosome 11. Lilium rosthornii showed enriched banding in both Giemsa C-banding and PI painting. Interestingly, not all 45S rDNA was located in homologous chromosomal locations. These results may provide reference data for L. rosthornii for use in further Lilium breeding.
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Çelik, Mustafa, Yavuz Bağcı, Esra Martin, and Halil Eroğlu. "Karyotype analysis and karyological relationships of Turkish Bunium species (Apiaceae)." Archives of Biological Sciences 72, no. 2 (2020): 203–9. http://dx.doi.org/10.2298/abs200122014c.
Full textAbstract:
Chromosomal data and karyological relationships provide valuable information about karyotype evolution and speciation. For the genus Bunium, the chromosomal data are limited. In the present study, the chromosomal data of 10 taxa are provided, 6 of which are given for the first time, 2 present new chromosome numbers, and 2 agree with previous reports. Four different chromosome numbers (2n=18, 20, 22 and 40) were detected, and 2n=40 is a new number in the genus Bunium. B. brachyactis is the first polyploid species of the genus with a ploidy level of 4x. The most asymmetric karyotypes are those of B. pinnatifolium and B. sayae. Regarding karyological relationships, B. pinnatifolium forms a monophyletic group by quite different karyological features such as large chromosomes, more submedian chromosomes and the most asymmetric karyotypes. In addition, the other 5 taxa form a strong monophyletic group. B. verruculosum and B. ferulaceum are cytotaxonomically very close species, as are B. sayae and B. elegans var. elegans. The chromosome numbers of 2 Turkish species, B. nudum and B. sivasicum, remain unknown. The presented results provide important contributions to the cytotaxonomy of Bunium.