scispace - formally typeset
Search or ask a question

Showing papers on "Karyotype published in 1983"


Journal ArticleDOI
TL;DR: It is shown that the homogeneously staining regions of the COLO 320 HSR marker chromosome contain amplified c- myc, and it seems reasonable to suspect that amplification of c-myc may have contributed to tumorigenesis.
Abstract: Two human neuroendocrine tumor cell lines derived from a colon carcinoma contain either numerous double minute chromosomes (COLO 320 DM) or a homogeneously staining marker chromosome (COLO 320 HSR). We found amplification and enhanced expression of the cellular oncogene c-myc in both COLO 320 DM and HSR cells, and we were able to show that the homogeneously staining regions of the COLO 320 HSR marker chromosome contain amplified c-myc. From previous and present karyotypes, it appears that the homogeneously staining regions reside on a distorted X chromosome. Therefore, amplification of c-myc has been accompanied by translocation of the gene from its normal position on chromosome 8 (8q24). Because double minute chromosomes were features of primary cultures from the original tumor, it seems reasonable to suspect that amplification of c-myc may have contributed to tumorigenesis.

698 citations


Journal ArticleDOI
01 Nov 1983-Nature
TL;DR: In this article, the translocation of the human cellular homologue (c-ab1) of the transforming sequence of Abelson murine leukaemia virus (A-MuLV) from chromosome 9 to the Philadelphia chromosome (Ph1) in chronic myelocytic leukemiaemia (CML) was investigated.
Abstract: The localization of cellular oncogenes near the break points of tumour-specific chromosomal aberrations suggests an involvement of these genes in the generation of neoplasms. Recently, we demonstrated the translocation of the human cellular homologue (c-ab1) of the transforming sequence of Abelson murine leukaemia virus (A-MuLV) from chromosome 9 to the Philadelphia chromosome (Ph1) in chronic myelocytic leukaemia (CML). In an attempt to investigate the significance of this translocation in the pathogenesis of CML, we have now studied two CML patients with complex translocations, t(9; 11; 22) and t(1; 9; 22), and two CML Ph1-negative patients with apparently normal karyotypes. In addition to using blot hybridization with human c-ab1 probes and DNA from rodent: CML cell hybrids as before, we have used in situ hybridization of these probes directly to metaphase chromosomes of CML patients. These studies show that the c-ab1 gene is translocated in Ph1-positive but not in Ph1-negative CML patients. CML without the Ph1 chromosome seems to be a distinct entity with a different origin, and this view is supported by clinical observations including correlations which reveal a poorer prognosis.

691 citations


Journal Article
TL;DR: It is concluded that essentially all lymphomas have cytogenetic abnormalities and it will be of interest to see if oncogenes are found in the regions of these chromosome abnormalities.
Abstract: G-banded chromosomes were studied from involved lymph nodes or other tumor masses in 94 patients with malignant lymphoma. Clonal chromosome abnormalities were identified in 91 patients including all 81 B-lymphomas but only 6 of 9 T-lymphomas. Many recurring chromosome abnormalities were found. Most common numerical alterations involved gains of chromosomes 12 (19% of patients), 18 (13%), 7 (12%), and 21 (10%). Structural abnormalities, which were more frequent than numerical alterations, most commonly involved chromosome regions 14q (71% of patients), 18q (36%), 6q (31%), 1p (24%), and 8q (19%). Seven recurring translocations were identified, and all except one involved 14q32. The most frequent were t(14;18)(q32;q21) in 22 patients, t(8;14)(q24;q32) in 9 patients, and t(1;14)(q42;q32) in 3 patients. Deletions most frequently involved the long arm of chromosome 6 at band q21 (11 patients) or q23 (7 patients). The common recurring chromosome abnormalities were correlated with histology (International Working Formulation for Clinical Usage) and immunological phenotype. Four abnormalities were significantly associated with specific histologies. Eighteen (82%) patients with t(14;18)(q32;q21) were follicular. Similarly, 82% of patients with del(6)(q21) were large cell lymphomas. Lymphomas with trisomy 7 were either diffuse large cell or follicular, while patients with t(8;14)(q24;q32) were either diffuse large cell or small noncleaved cell. A significant association with immunological phenotype was seen for t(14;18) only. All patients were either B- or complement lymphomas, and the heavy chain(s) was more commonly gamma and less frequently delta mu than among the total B-lymphoma population. We conclude that essentially all lymphomas have cytogenetic abnormalities; further study is required to determine their significance. Particularly, it will be of interest to see if oncogenes are found in the regions of these chromosome abnormalities.

336 citations


Journal ArticleDOI
TL;DR: It is shown that the resolution of in situ hybridization can be increased by hybridizing the probe to stretched prometaphase chromosomes with high-resolution banding obtained after 5-bromodeoxyuridine treatment of the cells and with a Hoechst 33258/Giemsa chromosome-staining method.
Abstract: The method of in situ hybridization has become a significant technique for specific-site chromosome mapping. We show that the resolution of in situ hybridization can be increased by hybridizing the probe to stretched prometaphase chromosomes with high-resolution banding obtained after 5-bromodeoxyuridine treatment of the cells and with a Hoechst 33258/Giemsa chromosome-staining method. Using this procedure, we assigned to specific chromosome sites three cloned genes and one DNA polymorphism: amylase gene (AMY) to 1p21; proopiomelanocortin gene (POMC) to 2p23, somatostatin gene (SST) to 3q28, and a single copy DNA segment (D3S1) to 3q12.

263 citations


Journal Article
TL;DR: It is suggested that DES induces chromosome nondisjunction, and possible mechanisms for DES-induced aneuploidy and the evidence supporting a role for nonrandom numerical chromosome changes in neoplastic development, as well as significance of aneuPLoidy in cancer, are discussed.
Abstract: Diethylstilbestrol (DES) has been demonstrated previously to induce morphological and neoplastic transformation of Syrian hamster embryo cells in the absence of any measurable induction of gene mutation. To determine if DES induces cell transformation by a genetic mechanism at the chromosomal level, the effect of DES on structural aberrations and numerical chromosome changes was examined in asynchronous and synchronized cells. Over the concentration range which is optimal for cell transformation, DES failed to induce any increase in chromosome aberrations in the cells. In contrast, significant numerical chromosome changes were observed in DES-treated cultures. The percentage of metaphases with a near diploid chromosome number increased to 19% at 48 hr after treatment. By comparison, cells from control cultures contained only 1 to 2% aneuploid metaphases with a near diploid chromosome number. No significant increase in the number of metaphases with a near tetraploid number (>70) of chromosomes was observed in the DES-treated cultures. DES induced both chromosome loss and gain, and no significant difference was detected between the number of hyperdiploid and hypodiploid cells. Chromosome loss or gain was observed for chromosomes in each karyotype group. These findings suggest that DES induces chromosome nondisjunction. Synchronized cell cultures were obtained by first growing the cells in 1% serum and then in 10% serum with hydroxyurea which blocked the cells at the G1-S border. Upon release of the hydroxyurea block, the cells entered into S phase in a very synchronous manner. The cells were treated for 3 hr during one of four time periods after hydroxyurea release. During the first period, the cells were primarily in early S phase, while the second period included cells in late S phase. During the third period most of the cells were undergoing mitosis, while in the fourth period most of the cells were in G1 phase, although some mitotic cells were observed. Treatment of the synchronized cells with DES during early or late S phase resulted in little morphological transformation. However, treatment during the third period, when the majority of the cells were in mitosis, resulted in a peak of transformation which was 15 times the level observed in cultures treated in early or late S phase. Treatment during the fourth time period resulted in a reduced level of cell transformation. Treatment of synchronized cultures with DES resulted also in a cell cycle-dependent induction of aneuploid cells which paralleled the induction of cell transformation, with the greatest level observed following treatment during mitosis. No increase in the percentage of polyploid metaphases or chromosome aberrations was observed in the DES-treated synchronized cells. Parallel dose-response curves for cell transformation and aneuploidy induction by DES were observed when the synchronized cultures were treated during the mitotic phase of the cell cycle. Possible mechanisms for DES-induced aneuploidy and the evidence supporting a role for nonrandom numerical chromosome changes in neoplastic development, as well as significance of aneuploidy in cancer, are discussed.

216 citations


Journal ArticleDOI
TL;DR: It is suggested that karyotype studies with banding techniques should be done in children with features of Beckwith-Wiedemann syndrome and developmental delay or retardation.

210 citations


Journal ArticleDOI
01 May 1983-Nature
TL;DR: The findings are surprising in that two of the three embryos were chromosomally abnormal, and data on the DNA content of the nuclei in a further eight cases showed that ∼20% overall may be haploid.
Abstract: In vitro fertilization and embryo transfer is now an established treatment for certain forms of human infertility. High success rates have been reported following oocyte recovery and fertilization in vitro, the only major remaining difficulty being the high failure rate (80%) of implantation after replacement of the embryo into the mother. One possible reason for this failure of implantation is that some embryos may carry a lethal chromosome abnormality which does not allow development beyond the preimplantation stage. The need for information on the chromosomal status of early embryos fertilized and developed in vitro is recognized but two reported attempts to examine them have met with technical problems. Here we describe a method for examining chromosomes in 8-cell human embryos. Although we have made complete chromosome analyses for only three oocytes, our findings are surprising in that two of the three embryos were chromosomally abnormal. Data on the DNA content of the nuclei in a further eight cases showed that approximately 20% overall may be haploid.

177 citations


Journal ArticleDOI
16 Aug 1983-Copeia
TL;DR: A number of males with no apparent sex chromosome heteromorphism were observed but these fish were particularly common in some populations; these may represent areas in which the rearrangement resulting in a morphological difference between the X and Y chromosomes has not become fixed in the population.
Abstract: Most males showed a morphological difference between the X and Y chromosomes but a number of males with no apparent sex chromosome heteromorphism were observed. These fish were particularly common in some populations; these may represent areas in which the rearrangement resulting in a morphological difference between the X and Y has not become fixed in the population.

175 citations


Journal ArticleDOI
TL;DR: The results indicate that the c-myc oncogene is unrearranged and remains on the 8q+ chromosome of JI cells and that the breakpoint in this Burkitt lymphoma is within the region carrying V kappa genes.
Abstract: We have studied somatic cell hybrids between mouse myeloma and JI Burkitt lymphoma cells carrying a t(2;8) chromosome translocation for the expression of human kappa chains. and for the presence and rearrangements of the human c-myc oncogene and kappa chain genes. Our results indicate that the c-myc oncogene is unrearranged and remains on the 8q+ chromosome of JI cells. Two rearranged C kappa genes were detected: the expressed allele on normal chromosome 2 and the excluded kappa allele that was translocated from chromosome 2 to the involved chromosome 8 (8q+). The distribution of V kappa and C kappa genes in hybrid clones retaining different human chromosomes indicated that C kappa is distal to V kappa on 2p and that the breakpoint in this Burkitt lymphoma is within the region carrying V kappa genes. High levels of transcripts of the c-myc gene were found when it resided on the 8q+ chromosome but not on the normal chromosome 8, demonstrating that translocation of a kappa locus to region distal to the c-myc oncogene enhances c-myc transcription.

165 citations


Journal ArticleDOI
11 Feb 1983-Science
TL;DR: Genetic function of one parent may be retained despite a complete loss of its chromosomes, suggesting that genetic introgression is possible in the absence of complete donor chromosomes.
Abstract: Protoplasts of sexually incompatible species have been fused and in some combinations have given rise to somatic hybrid plants. Partial elimination of parental chromosomes from either species is common in such hybrids, but total chromosome loss has generally occurred only with phylogenetically unrelated pairings. Genetic function of one parent may be retained despite a complete loss of its chromosomes, suggesting that genetic introgression is possible in the absence of complete donor chromosomes. A model interspecific combination for such studies is the potato-tomato somatic hybrid for which numerous phenotypes and karyotypes are encountered at the outset, with a broader range observed in the second somatic generation.

148 citations


Journal ArticleDOI
30 Nov 1983-Nature
TL;DR: The karyotype of the HL-60 line is re-examined, using cells frozen at various times during its continuous passage at the Wistar Institute to look for chromosomal abnormalities that might be associated with the amplification of c-myc.
Abstract: Several unusual chromosome structures have been described in drug-resistant cell lines and in certain tumours. These structures include elongated homogeneously staining regions (HSRs), small extrachromosomal paired chromatin bodies (double minutes, DMs) and abnormally banded regions (ABRs) with strong but anomalous band patterns1–3. There is evidence that these are alternative forms of gene amplification, with HSRs breaking down to form DMs, and DMs integrating into the chromosome to generate HSRs and ABRs5–7. Recently, it was demonstrated that, compared with several normal leukaemia human cells, DNA sequences representing the human homologue of the onc gene of the avian myelocytomatosis virus (MC29), the so-called c-myc gene, were amplified in HL-60 cells11,12. This is a human pro-myelocytic leukaemia cell line established in the laboratory of one of us (R.C.G.) at the National Cancer Institute (Bethesda, Maryland) in 1977, and widely used for studies on myeloid and monocytic differentiation8–10. Amplification of the gene was present in primary leukaemic cells of the patient12, and DMs were noted in some of these cells as well as in early passages of the HL-60 line13. No structure resembling HSRs or ABRs were noted in karyotypic studies at this early stage13 and there were no alterations involving the long arm of chromosome 8 (8q), to which the c-myc gene has recently been mapped14–16. We have now re-examined the karyotype of the HL-60 line, using cells frozen at various times during its continuous passage at the Wistar Institute (Philadelphia, Pennysylvania) to look for chromosomal abnormalities that might be associated with the amplification of c-myc. We find that, beginning in 1979, HL-60 cells at the Wistar Institute no longer had DMs, but did show an abnormal 8q+ chromosome, replacing a normal chromosome 8, and representing an ABR reflecting the site of myc gene amplification.

Book
01 Jan 1983
TL;DR: Chromosome size, number and shape mitotic chromosomes chromosomes in meiosis chromosome banding polytene chromosomes lampbrush chromosomes visualization of transcription, Aimee H.Bakken and R.S.Hill in situ hybridization autoradiography measuring nuclear or chromosomal DNA safety and the law.
Abstract: Chromosome size, number and shape mitotic chromosomes chromosomes in meiosis chromosome banding polytene chromosomes lampbrush chromosomes visualization of transcription, Aimee H.Bakken and R.S.Hill in situ hybridization autoradiography measuring nuclear or chromosomal DNA safety and the law. Appendix: names and addresses of suppliers.

Journal ArticleDOI
TL;DR: Comparison between the CNE‐2 and CNE, another epithelial cell line, showed that while they were quite different in many cytogenetic aspects, they had three marker chromosomes in common, namely, an iso8q, a t(?;3q) and a small acrocentric one.
Abstract: An epithelial cell line, CNE-2, has been recently established from a poorly differentiated nasopharyngeal carcinoma, and it represents the first of its kind. Using chromosome banding techniques, cytogenetic analysis of the cell line was carried out. It was demonstrated that the chromosome numbers of the CNE-2 cells varied from 87 to 107 and the modal number was 104-103. All cells contained a series of structurally abnormal chromosomes, and most of them were either consistent or frequently found. Among these chromosomes there were two giant markers which, by banding pattern analysis, proved to be distinct from the so-called giant group A marker chromosomes previously found in many lymphoblastoid cell lines from NPC. Comparison between the CNE-2 and CNE, another epithelial cell line, which was established from well-differentiated squamous NPC, showed that while they were quite different in many cytogenetic aspects, they had three marker chromosomes in common, namely, an iso8q, a t(?;3q) and a small acrocentric one. The question of whether chromosome markers specific for NPC exist is discussed in the light of the data presented.

Journal Article
TL;DR: Chinese hamster cell strains, each initiated from a separate fetus, were carried in culture and tested for tumorigenicity and in vitro indicators of neoplasia at various passage levels, and detailed studies of one lineage showed that transformation indicators, in general, correlated with tumors but did not indicate whether or not a preneoplastic, permanent lineage would rapidly progress.
Abstract: Chromosomes from successive passages of a Chinese hamster cell strain (WCHE/5) that spontaneously progressed from a euploid primary cell culture to a heteroploid tumorigenic cell line were isolated and analyzed by Giemsa banding and high-resolution flow karyotype analysis. The frequency and identification of aneuploid and marker chromosomes were determined at both pre- and postcrisis culture stages and pre- and posttumorigenic stages. The combination of Giemsa banding and flow karyotypes provided detailed analysis of karyotype instability at each stage of cell culture progression. Aneuploidy (trisomy of chromosome 5) preceded the appearance of tumorigenicity in nude mice as well as in vitro indicators of neoplasia. The four stages of neoplastic progression defined in the previous paper correlated with a steady progression in karyotypic instability, including, in sequence: trisomy of chromosome 5; an 8q marker chromosome; a 3q+ insertion; and trisomy of chromosome 8. Additional changes continued to appear as the cells acquired classical properties of in vitro transformation.

Journal ArticleDOI
TL;DR: Results indicate that the KCL-22 cells were derived from chronic myelogenous leukemia cells, a cell line that possessed receptors for the Fc portion of IgG, but lacked lymphoid cell characteristics and the Epstein-Barr virus-associated nuclear antigen.
Abstract: A new hematopoietic cell line, designated KCL-22, was established in vitro by cultivation of pleural effusion cells obtained from a woman with chronic myelogenous leukemia in blast crisis. KCL-22 grew in suspension culture with a doubling time of 24 h and consisted of immature undifferentiated cells which were positive for periodic acid-Schiff and acid phosphatase staining. Chromosome analysis of the KCL-22 line showed a female karyotype with double Ph1 chromosomes and additional chromosome abnormalities. Its representative karyotype was 52,XX, + 1p-,+6,+8,+8,+8, t(9q+;22q-), +22q-. This cell line possessed receptors for the Fc portion of IgG, but lacked lymphoid cell characteristics and the Epstein-Barr virus-associated nuclear antigen. These results indicate that the KCL-22 cells were derived from chronic myelogenous leukemia cells. This cell line should prove useful for research involving various aspects of chronic myelogenous leukemia.

Journal ArticleDOI
TL;DR: A comparison of results with previously published studies suggests that chromosome 6q may represent a specific site of chromosome aberration in malignant melanoma.

Journal ArticleDOI
TL;DR: A recombinant phage library is constructed that is enriched for DNA present in the HSR of this chromosome by using fluorescence-activated flow sorting for initial chromosome purification and demonstrated that cloned HSR segments were localized in the short arm of chromosome 2 in both normal and IMR-32 cells.
Abstract: Human neuroblastoma IMR-32 cells have large homogeneously staining regions (HSRs), primarily in the short arms of chromosome 1. We have constructed a recombinant phage library that is enriched for DNA present in the HSR of this chromosome by using fluorescence-activated flow sorting for initial chromosome purification. Eleven distinct cloned DNA segments were identified that showed significantly greater hybridization to IMR-32 genomic DNA, detected by Southern blotting, than to normal human genomic DNA. These sequences have also been localized to the HSR of chromosome 1 by in situ hybridization. Based on an approximate 50-fold sequence amplification for each cloned segment and a total HSR size of 150,000 kilobases, the amplified unit in the HSR is estimated to be 3,000 kilobases. Sequences homologous to all cloned HSR DNA segments were mapped to human chromosome 2 by using human-mouse hybrid cells. Further work using in situ hybridization demonstrated that cloned HSR segments were localized in the short arm of chromosome 2 in both normal and IMR-32 cells. Thus, the amplification of these sequences in IMR-32 cells may have involved transposition from chromosome 2 to chromosome I.

Journal ArticleDOI
TL;DR: A detailed technique is described for obtaining preparations of the chromosome complements of human sperm by fertilization of hamster eggs and analysis of the male pronucleus.
Abstract: A detailed technique is described for obtaining preparations of the chromosome complements of human sperm by fertilization of hamster eggs and analysis of the male pronucleus. Some of the more difficult aspects and important steps are emphasized. Technical data from 17 consecutive experiments are presented to provide an estimate of the number of karyotypes which can be obtained in an experiment.

Journal Article
TL;DR: It was suggested that the genesis of myeloid leukemia was greatly influenced by the genetic information on chromosome 2 in mice, and it was found that the chromosomal segment lying between Regions 2C and 2D was commonly missing from all of the deleted No. 2 chromosomes.
Abstract: Chromosomes of 52 cases of mouse myeloid leukemia were examined. There were 5 myeloblastic leukemias, 22 granulocytic leukemias, 17 myelomonocytic leukemias, and 8 monocytic leukemias. Fifty cases were radiation induced and the other 2 were nonirradiated. Each case had leukemic cells with 1 to 10 marker chromosomes. Partially deleted No. 2 chromosomes appeared in 49 cases, including 2 nonirradiated cases. These deleted No. 2 chromosomes were varied in size, and they were classified into 7 types according to morphological features. There was no type-dependent difference in histological or cytological features among the 7 types. It was found that the chromosomal segment lying between Regions 2C and 2D was commonly missing from all of the deleted No. 2 chromosomes. In addition to such No. 2 chromosomes, an anomaly in chromosome 6 was observed in 16 cases, of which 12 cases were granulocytic leukemia. The abnormalities of chromosomes 3 and 9 were next most frequent, appearing in 14 cases each. Besides such structural anomalies, numerical changes involving the Y chromosome (33 cases), chromosome 6 (6 cases), and chromosome 15 (4 cases) were also found. Characteristics of the karyotypes of the mouse myeloid leukemia in comparison with other leukemias were noted. The significance of the specific segments of the chromosomes which were commonly missing or trisomic in the karyotypes of neoplasias in mice, rats and humans was discussed. It was suggested that the genesis of myeloid leukemia was greatly influenced by the genetic information on chromosome 2 in mice.

Journal ArticleDOI
16 Dec 1983-Science
TL;DR: Fragments of the recently cloned human gene for the beta subunit of nerve growth factor (beta-NGF) were used as hybridization probes in analyzing two sets of rodent-human somatic cell hybrids for the presence of human beta- NGF sequences.
Abstract: Fragments of the recently cloned human gene for the beta subunit of nerve growth factor (beta-NGF) were used as hybridization probes in analyzing two sets of rodent-human somatic cell hybrids for the presence of human beta-NGF sequences. Results from the first set of hybrids assigned the human beta-NGF gene to chromosome 1 and ruled out the presence of sequences of comparable homology on any other chromosome. With the second set of hybrids, which contained seven different, but overlapping, regions of chromosome 1, the NGF locus was mapped to band 1p22.

Journal ArticleDOI
TL;DR: It is proposed that integration of DNA may disrupt telomeric structures and facilitate the formation of dicentric chromosomes, which may then undergo bridge breakage-fusion cycles.
Abstract: A modular dihydrofolate reductase gene has been introduced into Chinese hamster ovary cells lacking dihydrofolate reductase. Clones capable of growth in the absence of added nucleosides contain one to five copies of the plasmid DNA integrated into the host genome. Upon stepwise selection to increasing methotrexate concentrations, cells are obtained which have amplified the transforming DNA over several hundredfold. A detailed analysis of the chromosomes in three clones indicated the appearance of cytologically distinct chromosomal regions containing the amplified plasmid DNA which differ in surrounding sequence composition, structure, and location. Two of the clones examined have extensive, homogeneously staining regions. The DNA in these homogeneously staining regions replicates in the early part of the S phase. The amplified plasmid DNA is found associated at or near the ends of chromosomes or on dicentric chromosomes. We propose that integration of DNA may disrupt telomeric structures and facilitate the formation of dicentric chromosomes, which may then undergo bridge breakage-fusion cycles. These phenomena are discussed in relation to DNA transfer experiments and modes of gene amplification and chromosome rearrangement.

Journal ArticleDOI
TL;DR: In this paper, a study was carried out on mitotic and meiotic chromosomes of four species of the genus Astyanax from three different water basins in the State of Sao Paulo, Brazil.
Abstract: SUMMARYA study was carried out on mitotic and meiotic chromosomes of four species of the genus Astyanax (Pisces, Characidae) from three different water basins in the State of Sao Paulo, Brazil. The following karyotypic characteristics were observed: A. bimaculatus, 2n = 50 (n = 25, FN = 86–88); A. fasciatus, 2n = 46 (n = 23, FN = 90); « A. fasciatus » from the Juquia river, 2n = 48 (n = 24, FN = 94); A. schubarti, 2n = 36 (n = 18, FN = 70) and A. scabripinnis paranae, 2n = 50 (n = 25, FN = 90–92). The diversity in the number and morphology of the chromosomes suggests a model of non-conservative karyotypic evolution in this genus, with chromosome rearrangements of the centric fusion/fission type and/or inversion playing an important role in these alterations. On the basis of its characteristics, A. schubarti has the most differentiated karyotype and, in view of the low diploid number and small number of subtelocentric-acrocentric chromosomes, is probably of most recent origin. The two karyotypes encountere...

Journal ArticleDOI
TL;DR: Chromosome elimination was studied in squash preparations of seeds of two different Hordeum crosses between diploid parents whose karyotypes allowed identification with unusual ease for Hordeum of the parental origins of the chromosomes being eliminated in each mitosis in embryos and endosperms.
Abstract: Chromosome elimination was studied in squash preparations of seeds of two different Hordeum crosses between diploid parents whose karyotypes allowed identification with unusual ease for Hordeum of the parental origins of the chromosomes being eliminated in each mitosis in embryos and endosperms. In both crosses, the mean chromosome number in hybrid tissues fell during several mitoses until nuclei became haploid in embryos and diploid in endosperms. Elimination was always uniparental, i.e. all chromosomes eliminated from a given tissue in a given cross were from the same parent. In H. marinum x H. vulgare cv. Tuleen 346, elimination involved the Tuleen 346 genome in the endosperm, but the H. marinum genome in the embryo. This is a good example of alternative elimination, i.e. uniparental elimination involving different parental genomes in different tissue of the same cross. In Tuleen 346 x H. bulbosum, the H. bulbosum genome was eliminated from both embryos and endosperms. — In H. marinum x Tuleen 346 endosperms, eliminated Tuleen 346 chromosomes were individually identifiable and tended to be eliminated in non-random order: the nucleolar chromosomes, T3-7 and T6-2 first, followed by chromosomes T5-1, T7-3, T2-6 and 4, with chromosome T1-5 last. — The nucleolar constrictions were expressed in eliminated satellite chromosomes from Tuleen 346, but not in those from H. marinum or H. bulbosum. Eliminated chromosomes differed from retained ones in having smaller centromeres and tending before, during and after elimination to occupy more peripheral regions of mitoses. Elimination may result primarily from specific suppression of genes involved in centromere function, perhaps by DNA methylation.

Journal Article
TL;DR: A de novo interstitial deletion of 6q21 was observed in a male baby with moderate microcephaly, facial dysmorphism, and psychomotor retardation and in situ hybridization showed that the gene was conserved on the deleted chromosome.
Abstract: A patient with multiple congenital malformations and developmental delay is reported. Her karyotype is 46,XX,del(3)(q23q25).

Journal ArticleDOI
TL;DR: The mitotic and meiotic chromosomes of the marsupial frog Gastrotheca riobambae were analysed with various banding techniques and it is shown that the constitutive heterochromatin in the Y chromosome consists of at least three different structural categories.
Abstract: The mitotic and meiotic chromosomes of the marsupial frog Gastrotheca riobambae were analysed with various banding techniques. The karyotype of this species is distinguished by considerable amounts of constitutive heterochromatin and unusual, heteromorphic XY sex chromosomes. The Y chromosome is considerably larger than the X chromosome and almost completely heterochromatic. The analysis of the banding patterns obtained with GC- and AT-base-pair-specific fluorochromes shows that the constitutive heterochromatin in the Y chromosome consists of at least three different structural categories. The only nucleolus organizer region (NOR) of the karyotype is localized in the short arm of the X chromosome. This causes a sex-specific difference in the number of NOR: female animals have two NORs in diploid cells, male animals one. No cytological indications were found for the inactivation of one of the two X chromosomes in the female cells. In male meiosis, the heteromorphic sex chromosomes form a characteristic sex-bivalent by pairing their telomeres in an end-to-end arrangement. The significance of the XY/XX sex chromosomes of G. riobambae for the study of X-linked genes in Amphibia, the evolution of sex chromosomes and their specific DNA sequences, and the significance of the meiotic process of sex chromosomes are discussed.

Journal ArticleDOI
TL;DR: It is suggested that these cytogenetic findings raise the possibility that a single deletion event occurring at an early stage during the isolation of these lines may confer a selective advantage to those cells carrying the deleted X chromosome.
Abstract: The karotype of six pluripotential stem cell lines derived from haploid and two additional lines derived from diploid parthenogenetic embryos is described. All these lines are diploid and possess a normal autosomal complement. The stage at which diploidization of the haploid cells occurs is not yet known. The XX-chromosome complement in these lines is unstable, although in two haploid-derived lines and one diploid-derived line many normal XX-bearing cells are found in early cultures. All of the lines so far examined either become XO (rarely), or a single X-chromosome shows a deletion in the distal region. The extent of this deletion varies between lines, but the position of the breakpoint appears to be constant for a given line. We suggest that these cytogenetic findings raise the possibility that a single deletion event occurring at an early stage during the isolation of these lines may confer a selective advantage to those cells carrying the deleted X chromosome.

Journal ArticleDOI
TL;DR: Using an in situ molecular hybridization method, three sites on the human pachytene chromosomes that exhibited significant hybridization to v-Ki-ras and v-Ha-ras probes are detected.
Abstract: The c-ras family is a set of c-onc genes that are highly conserved in vertebrates. The genes in this family are homologous to the transforming genes of Harvey and Kirsten murine sarcoma viruses (v-Ha-ras and v-Ki-ras, respectively). Using an in situ molecular hybridization method, we detected three sites on the human pachytene chromosomes that exhibited significant hybridization to v-Ki-ras and v-Ha-ras probes. These were chromomere positions that corresponded to bands 11p14.1, 12p12.1, and 12q24.2 of somatic chromosomes. The relationship between these chromosomal sites and previously defined members of the human c-ras gene family is discussed. These chromosomal sites are known to be involved in specific chromosome changes in a variety of tumors and in several congenital disorders that predispose to neoplastic disease.

Journal ArticleDOI
TL;DR: It is proposed that the effect of the trisomy 21 condition on spermatogenesis (and fertility) is a consequence of the behavior of the extra chromosome in the meiotic prophase.
Abstract: Studies on testicular histology and meiosis were carried out by the use of light and electron microscopy in an 18-year-old Down's syndrome male in an attempt to follow the fate of the extra chromosome 21 and to evaluate the effects of this condition on spermatogenesis and the reproductive functions. The histological changes in the testes corresponded to spermatogenic arrest. Electron microscopic whole-mount spreadings of meiotic cells in the pachytene stage showed that in most nuclei an extra chromosome 21 was not detectable. Only in a small number of nuclei, univalents or trivalents with segmental pairing structures of an extra chromosome could be discovered. In contrast, the great majority of (C-banded) diakinesis figures showed the presence of a supernumerary G (no. 21) chromosome. The absence of a traceable extra chromosome 21 in most pachytene cells is explained by the assumption that it is intimately connected with and hidden in the sex vesicle, whose complex structure does not allow the identification of single elements. Strong support for this assumption is seen (a) in the general tendency of narrow spatial association of unpaired segments with the XY complex and (b) in close structural similarities occurring between univalents or nonsynapsed segments of trivalents and the nonpaired segments of the sex chromosomes. It is suggested that the association or connection of an extra chromosome with the XY complex during pachytene interferes with the phenomenon of X inactivation. In animal systems such abnormal interference is related with spermatogenic breakdown and, in a general way, with male hybrid type sterility. So far, the range of sterility vs. fertility in cases of male Down's syndrome is not yet fully clear, but it appears that impairment of fertility, and sterility are most frequent. If so, it is proposed that the effect of the trisomy 21 condition on spermatogenesis (and fertility) is a consequence of the behavior of the extra chromosome in the meiotic prophase.

Journal ArticleDOI
TL;DR: It is concluded that Anguilla anguilla has no heteromorphic sex chromosomes and it is tentatively hypothesized that sex determination in A. anguillas may be metagamic and that sex inversion may occur in this species.
Abstract: Metaphase chromosomes from cultured blood cells of female, male, and hermaphroditic European eels were analyzed. In addition, both gonads from each of the specimens were examined microscopically to ensure correct sexing. The karyological investigation revealed that in some of the specimens a heteromorphic chromosome pair was present. This heteromorphism appeared in both sexes and in the hermaphrodite. C-banding and silver nitrate staining demonstrated that the heteromorphism was due to quantitative differences in constitutive heterochromatin and nucleolar organizing regions in the short arm of chromosome 8. In G-banded preparations it was demonstrated that, except for the heteromorphism mentioned, the karyotypes from both sexes and the hermaphrodite were identical. With the G-band technique it was also easily demonstrated that both the largest metacentric (No. 1) and the smallest metacentric (No. 11) had homologs. Therefore, in contrast to some earlier reports which claimed that these two chromosomes were a heteromorphic pair of sex chromosomes, it is concluded that Anguilla anguilla has no heteromorphic sex chromosomes. The implication of these findings are discussed in relation to the many reports of strongly skewed sex ratios found in commercial eel farms. It is tentatively hypothesized that sex determination in A. anguilla may be metagamic and that sex inversion may occur in this species.

Journal Article
TL;DR: It is suggested that abnormalities involving chromosomes 6 and 7 may be a characteristic feature of MM, and Aberrations of chromosome 1, although common in MM, may be part of a general cytogenetic feature in human neoplasia.
Abstract: Chromosome aberrations were analyzed in 4 cases of malignant melanoma (MM) after disaggregation of the tumors with collagenase and short-term culture. In all cell cultures, the MM cells displayed a typical triangular spindle form. The chromosome number was near-diploid in one case and near-triploid in three cases. A total of 27 abnormal chromosomes were identified with the Giemsa banding technique. By far, the most common types of abnormalities were translocations, followed by deletions and isochromosomes. Chromosomes 1, 6, and 7 were found to be most frequently involved in structural aberrations. Markers originating from chromosomes 1 and 6 were found in all four cases, and abnormalities of chromosome 7 were found in three. Each marker chromosome was unique for a given case; no common markers for two or more cases were found. Based on the present results and an analysis of reports on the chromosomal constitution of MM cells in the literature, we suggest that abnormalities involving chromosomes 6 and 7 may be a characteristic feature of MM. Aberrations of chromosome 1, although common in MM, may be part of a general cytogenetic feature in human neoplasia.