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PubMed2026

Satellite DNA evolution in Tytonidae (Aves: Strigiformes): dynamic repeat landscapes despite conserved karyotypes.

The elevated chromosome numbers observed in Tytonidae relative to the putative ancestral avian karyotype suggest that lineage-specific chromosomal fissions may have played an important role in the evolutionary history of this family. Here, we provide the first cytogenetic characterization of the American barn owl (Tyto furcata) and performs a comparative repeatome analysis across members of the Tytonidae, including other two species, the Western barn owl (Tyto alba), and the Oriental bay owl (Phodilus badius). The karyotype of T. furcata showed a 2n = 92, closely resembling that previously described for T. alba, indicating a high degree of chromosomal conservation within Tytonidae. Although T. furcata and T. alba exhibit similar karyotypic organization, comparative repeatomic analyses revealed differences in their composition, including variation in satellite DNA (satDNA) repertoires and abundance. Eight satDNA families were identified in T. furcata, nine in T. alba, and 28 in P. badius, highlighting the dynamic evolution of repetitive sequences. Several satDNA families were shared between T. furcata and T. alba, whereas some appeared species-specific, supporting the library hypothesis of satDNA evolution. In P. badius, multiple satDNAs exhibited similarity to transposable elements, suggesting that mobile elements contributed to their diversification. Cytogenetic analyses demonstrated centromeric heterochromatin distribution in T. furcata, as well as a large heterochromatic W chromosome enriched in DNA repeats. The localization of satDNAs in centromeric regions and the apparent accumulation of repeats on the W chromosome reinforce the role of repetitive sequences in chromosome organization and sex chromosome differentiation. Together, these findings reveal repeatome diversification despite conserved macrochromosomal structure and provide new insights into genome evolution and chromosomal dynamics in birds.

Animals↗
PubMed1996

Chromosomal evolution in duiker antelope (Cephalophinae: Bovidae): karyotype comparisons, fluorescence in situ hybridization, and rampant X chromosome variation.

Fluorescence in situ hybridization (FISH) and conventional banding techniques were used to identify patterns of similarity among the genomes of six species of antelope, subfamily Cephalophinae. The G-banded euchromatic portions of the autosomes were invariable in all species; however, significant modifications of the X chromosomes were detected. Two of the taxa, Cephalophus maxwellii and C. monticola, were characterized by acrocentric X's, while X chromosome morphology varied from submetacentric to metacentric in the remaining species (C. dorsalis, C. natalensis, Sylvicapra grimmia, and C. silvicultor). The short arm of the X was heterochromatic in each species. Total genomic DNAs from these antelope were used as hybridization probes against Cephalophus metaphase chromosomes and resulted in robust fluorescence in the pericentromeric region of each autosome and in the heterochromatic short arm of the X chromosome, indicating complimentarity of DNA sequences in these regions. Conversely, chromosome painting involving genomic DNAs derived from the subfamilies Alcelaphinae (Pygargus dorcas) and Neotraginae (Oreotragus oreotragus) showed a marked absence of hybridization at these sites. Additionally, X chromosome comparisons between the Cephalophinae and Bovinae (represented by Bos taurus) revealed two euchromatic pericentric inversions which had occurred since their common ancestry. There is good G-band homoeology between the inverted cattle chromosome region Xq12 --> q34 and most of the proximal portion of Xq in duikers, as well as between the distal third of the duiker Xq and the cattle Xp. The latter rearrangement was further confirmed by in situ hybridization using a probe containing an insert spanning bands p12 to p14 of the cattle X chromosome.

Animals↗
PubMed1999

Chromosome evolution in kangaroos (Marsupialia: Macropodidae): cross species chromosome painting between the tammar wallaby and rock wallaby spp. with the 2n = 22 ancestral macropodid karyotype.

Marsupial mammals show extraordinary karyotype stability, with 2n = 14 considered ancestral. However, macropodid marsupials (kangaroos and wallabies) exhibit a considerable variety of karyotypes, with a hypothesised ancestral karyotype of 2n = 22. Speciation and karyotypic diversity in rock wallabies (Petrogale) is exceptional. We used cross species chromosome painting to examine the chromosome evolution between the tammar wallaby (2n = 16) and three 2n = 22 rock wallaby species groups with the putative ancestral karyotype. Hybridization of chromosome paints prepared from flow sorted chromosomes of the tammar wallaby to Petrogale spp., showed that this ancestral karyotype is largely conserved among 2n = 22 rock wallaby species, and confirmed the identity of ancestral chromosomes which fused to produce the bi-armed chromosomes of the 2n = 16 tammar wallaby. These results illustrate the fission-fusion process of karyotype evolution characteristic of the kangaroo group.

Animals↗
PubMed1984

Clonal evolution with isodicentric Ph1 chromosome in Ph1-positive CML: karyotypic conversion after bone marrow transplantation.

Clonal chromosomal evolution was observed in a 16-year-old boy suffering from Ph1-positive CML. An isodicentric Ph1 chromosome appeared 20 weeks after the initial diagnosis. At that time an allogeneic bone marrow transplantation was performed. Thereafter, during an observation period of more than 13 months, chromosome analyses showed neither the Ph1 chromosome nor the abnormal isodicentric variant. Close cytogenetic monitoring is suggested to reveal early unfavorable prognostic signs of the onset of blast crisis before it becomes evident in the bone marrow morphology.

Adolescent↗
PubMed1997

[Karyological differentiation of three species of coarse-haired mice of the genus Lophuromys (Murinae, Rodentia) from the Bale Mountain National Part in Ethiopia].

Three karyotypically differentiated species of harsh-furred mice, Lophuromys melanonyx (2n = 60, NFa = 90; 24m,sm + 8st + 26a + Xm + Ya), Lophuromys sp. A (2n = 54, NFa = 60; 8m,sm + 44a + Xa + Ya), and Lophuromys sp. B (2n = 68, NFa = 78; 8m,sm + 4st + 54a + Xst + Ya), were found at the Bale Mountains National Park, Ethiopia. Comparative analysis of chromosomes showed that G-banding patterns of 2 to 17 chromosome banding patterns or chromosome arms were identical in all species. Apparently, the formation of the studied species was associated with their independent karyotypic divergence during early evolution. The results obtained indicate that the rate of karyotypic alterations is not associated with the degree of morphological differentiation in this group of species.

Animals↗
PubMed1991

Evolution of a near-triploid karyotype in a secondary erythroleukemia.

We report a case of erythroleukemia (EL;FAB M6), preceded by a myelodysplastic phase, in a 50-year-old male 8 years after treatment for Hodgkin's lymphoma. Cytogenetic analysis of bone marrow at time of diagnosis of EL revealed three cell lines: 1) 28 of 53 cells (53%) were hypodiploid, 43,XY,-5,-7,-12; 2) 23 of 53 cells (43%) were near-triploid, stemline 67-69,XY,+2,del(5)(q11.2),+del(5)(q11.2),+6,-7,+8,-9,-11,-12,+15,-16,der (17)t (17;?) (p11.2;?),-18,-20,-20,+22,+r, + mar (relative to a complete triploid cell); 3) 2 of 53 cells (4%) were normal 46,XY. The relative monosomies of 5, 7, and 12 in both abnormal lines suggest that the near-triploid line evolved from the hypodiploid line. A single hypodiploid cell with both del(5) and der(17) chromosomes that appeared identical to those in the near-triploid line suggests that polyploidization occurred after these structural rearrangements. While EL is not characterized by any well-defined structural abnormality, reported cases are frequently hypodiploid, with occasional cases of polyploidization, as in our patient, EL in adults without previous neoplasia or recognized mutagenic exposure has been shown to have loss or deletion of chromosomes 5 and 7, also characteristic of myelodysplastic syndromes and secondary leukemia. Our patient had a relative lack of chromosomes 5 and 7 in both abnormal clones, as well as a del(5)(q11) in the near-triploid line. This case of EL clearly demonstrates the evolution of a complex near-triploid line from a hypodiploid line, with chromosome abnormalities typical of both EL and secondary leukemia.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1993

Childhood myelodysplastic syndrome with clonal evolution progressing to acute megakaryoblastic leukemia (ANLL-M7).

We treated a 16-month-old girl with myelodysplastic syndrome (MDS; refractory anemia with excess of blasts subtype, RAEB by FAB classification) that developed into acute megakaryoblastic leukemia (ANLL-M7). The blast cells were positive for CD41 shown by flow cytometry and for platelet peroxidase by electron microscopy. Cytogenetically, five kinds of abnormal karyotypes were apparent at the initial visit and karyotypic progression (clonal evolution) was also evident. These karyotypes were considered to be derived from the putative original clone, 48,XX, +6, +21. The observed karyotypes were considered 50,XX, +4,add(4)(q31), +6,add(7)(p22),add(10)(q24),add(12)(q11), +20, +21, + mar[karyotype A];48,XX,add(4)(q31), +6,add(10)(q24),add(12)(q11), +21 [karyotype B];48,XX, +6,t(6;13)(p23;q14), +21 [karyotype C];51,XX, +X, t(6;13)(p23;q14), + der(6)t(6;13)(p23;q14), +21, +21, + mar [karyotype D]; and 49,XX, +X, -3,t(6;13)(p23;q14), +der(6)t(6;13)(p23;q14), -12, +21, +21, + mar [karyotype E]. It seems karyotypes B and C were derived from the putative clone; karyotype B developed into karyotype A; and karyotype C developed into karyotype E through karyotype D. After development of ANLL-M7, the cytogenetic study showed a karyotype with further karyotypic progression. The patient was treated with high-dose cytosine arabinoside (HD AraC) followed by allogeneic bone marrow transplantation. Despite intensive care, she died 3 months after the transplantation.

Anemia, Refractory, with Excess of Blasts↗
PubMed2006

Telomere-driven karyotypic complexity concurs with p16INK4a inactivation in TP53-competent immortal endothelial cells.

Critically short telomeres promote chromosomal fusions, which in TP53-defective cells initiate the formation of cytogenetic aberrations that are typical of human cancer cells. Expression of the enzyme telomerase stabilizes normal and aberrant chromosomes by maintaining telomere length. However, previous investigations, including our own, have shown that overexpression of telomerase reverse transcriptase (hTERT) does not prevent net telomere shortening in human endothelial cells. In the present study, two mass cultures of hTERT-transduced bone marrow endothelial cells (BMhTERT) and 26 clones were employed to further investigate the immortalization process and consequences of telomere shortening. Eighty-five percent (22 of 26) of the clones and both mass cultures were immortalized. However, cytogenetic analyses revealed recurring cytogenetic aberrations in the mass cultures and 12 representative clones. Several of the recurring aberrations, including +5p, +11, -13, +19, and +20, and nonreciprocal translocations involving 17p and 2p were previously implicated in human carcinogenesis. One mass culture and a subset of clones (5 of 12) had complex karyotypes, characterized by cytogenetic heterogeneity and at least five chromosomal abnormalities. p16(INK4a) was silenced exclusively in the five clones and mass culture with complex karyotypes, whereas the p53/p21(cip1) pathway was defective in only one clone. Telomere dysfunction was implicated in the evolution of complex karyotypes by the presence of anaphase bridges, telomere associations, and dicentric chromosomes. These results show that complex karyotypes can evolve in TP53-competent cells and provide evidence that p16(INK4a) functions as a gatekeeper to prevent telomere-driven cytogenetic evolution. These investigations provide new insight to the role of p16(INK4a) as a tumor suppressor.

Bone Marrow Cells↗
PubMed1980

Dysmyelopoietic syndrome: sequential clinical and cytogenetic studies.

Clinical and cytogenetic studies were done on 8 patients with dysmyelopoietic syndrome: 6 of these patients had refractory anemia with an excess of blasts (RAEB), and 2 patients had chronic myelomonocytic leukemia (CMML) according to the French-American-British classification. The ages of these 8 patients (3 female and 5 male) ranged from 45 to 70 yr (median, 61.5 yr). Seven of the 8 patients died 3-86 mo (median, 11 mo) after the onset of symptoms of hemorrhage or infections. Cytogenetic studies of bone marrow cells with the Q-banding technique showed clonal karyotypic abnormalities in 7 of the 8 patients (87.5%). Five of the 7 chromosomally abnormal patients had very complex karyotypes; all 7 patients, however, had at least 1 of 4 specific changes: -5 (or 5Q-), -7, +8, and +21. Three of the 7 patients with abnormal karyotypes had had some exposure to potential mutagenic/carcinogenic agents. Five of the 7 patients had serial cytogenetic analyses, 4 of which showed evolution of the karyotype to further complexity; in 2 cases, this coincided with the evolution of the disease into acute leukemia. The median survival time of patients whose initial cytogenetic samples showed both normal and abnormal metaphases was more than twice that of patients who had only abnormal metaphases initially (12 mo versus 4.5 mo).

Aged↗
PubMed1988

[Chromosome of transplantable lung adenocarcinoma cell line (LA-795)].

The chromosome patterns of lung adenocarcinoma cell line LA-795 were studied with G and C banding techniques at passages 60 and 100. The model chromosome numbers were 69, 68, 67 and 66. G banding of 46 cells of the four clones (69, 68, 67 and 66) were analysed. The chromosome patterns of this cell line were hypotetraploid male cells which were similar to those transplanted in mice. The 69 model chromosome comprises two types, 69I and 69II. According to the karyotype analysis, the evolution process of clone from 69 to 68, 67 and 66 was recognized by the karyotype of various clones. The lose of chromosome No. 4 and No. 14 in various model chromosome cell lines may be a non-random chromosome aberration of mouse tumor cells.

Adenocarcinoma↗
PubMed1981

Monoblastic transformation in chronic myelogenous leukemia: presentation with massive hepatic involvement.

Monoblastic transformation developed in a 26-year-old white man with chronic myelogenous leukemia and was manifested by acute, fulminant hepatic failure due to massive blastic infiltration of the liver. The hepatic failure responded dramatically to radiation therapy. The monocytic origin of the blasts was confirmed by means of light and electron microscopic examination and cytochemical studies. Cytogenetic studies of the leukemic blasts revealed a Philadelphia-chromosome-positive karyotype and a clonal evolution of chromosome changes resulting in multiple karyotypes.

Adult↗
PubMed1992

Cytogenetic analysis in relapsed childhood acute lymphoblastic leukemia.

The nature of the cytogenetic abnormalities present at relapse of childhood acute lymphoblastic leukemia (ALL) and their relationship to the disease and the karyotype at diagnosis have not been clearly defined. This report describes cytogenetic analyses of 50/51 consecutive relapsed childhood ALL patients. Evolution of the karyotype was common, with structural abnormalities particularly frequent. Rearrangements involving chromosome 1 occurred frequently, particularly in patients with greater than 50 chromosomes. In patients with less than or equal to 50 chromosomes, structural aberrations were often unbalanced, leading to loss of genetic material, but these did not show a predominance of chromosome 1 abnormalities. These differences among the cytogenetic groups of ALL are an indication that the chromosomal abnormalities occurring in ALL reflect different biological events underlying this disease, and that different biological processes are involved in the several cytogenetic groups of ALL patients not only at initiation, but also during the progression and evolution of the disease.

Adolescent↗
PubMed1995

Cytogenetic findings in 179 patients with myelodysplastic syndromes.

Cytogenetic analyses were performed on 266 bone marrow and peripheral blood samples from 179 patients with myelodysplastic syndromes (MDS). According to the FAB classification, 42 patients presented with RA, 18 with RARS, 37 with RAEB, 22 with CMML, and 29 with RAEB-T. Nine patients showed a secondary MDS (S MDS). FAB classification was not available for 22 patients. Clonal karyotype anomalies were found in 92 patients (51.4%). Complex chromosome abnormalities occurred in 17 (18.5%) of them. An evolution of the karyotype was detected in 16 cases (17.4%). Cytogenetically independent cells or cell clones were found in eight patients. Nonclonal chromosome abnormalities were uncovered in 29 (16.2%) of the 179 MDS patients. Consecutive studies were performed in 48 patients and revealed a good correlation of initial karyotype and clinical course. The most frequent single anomalies were 5q- in 29 (31.5%), -7 in 22 (23.9%), trisomy 1q in 14 (15.2%), and +8 in 13 (14.1%) of 92 patients respectively. Our cytogenetic findings are presented in detail and discussed in relation to patients' age, morphological classification, clinical course, and prognostic impact. The contribution of cytogenetic findings to the delineation of multistep pathogenesis of MDS with special emphasis to karyotype instability is demonstrated.

Adult↗
PubMed1995

Clarification of dubious karyotypes in Hodgkin's disease by simultaneous fluorescence immunophenotyping and interphase cytogenetics (FICTION).

Cytogenetic studies on Hodgkin's disease (HD) typically reveal very complex karyotypes with a variety of numerical and structural abnormalities. The confusing thing is that about 10% of cases contain relatively discrete chromosome aberrations, for example a simple trisomy or loss of one single chromosome. Whether these karyotypes really correspond to Hodgkin and Reed-Sternberg (HRS) cells is uncertain. They could, for example, represent early stages in the evolution of the karyotype of the pathognomonic HRS cells. On the other hand, they could be artificial events that occur during the cytogenetic procedure. In our experience, isolated loss of the Y chromosome is the most frequent finding of this type. This aberration is usually considered to be a preparation artifact. However, if one takes into account that in HD up to 50% of male cases with complex karyotypes also lack the Y chromosome, a possible relation to HRS cells must be considered. The technique of simultaneous fluorescence immunophenotyping and interphase cytogenetic analysis (referred to as FICTION) is a powerful tool for studying the nature of cytogenetically abnormal cells. With the FICTION technique we studied four cases of HD in which the chromosome analysis had shown only the loss of the Y chromosome. Our aim was to clarify whether these karyotypes corresponded to the CD30-positive HRS cells. In two cases we found that HRS cells actually lacked the Y chromosome. There was strong evidence, however, that the HRS cells additionally had other chromosome aberrations and thus could not correspond to the cytogenetically determined karyotypes.

Cytogenetics↗
PubMed1982

[The bone marrow karyotype in refractory anemia and preleukemia].

The term preleukemia may be used to refer to patients with acquired chronic cytopenias (refractory anemia with an excess of blast cells, refractory sideroblastic idiopathic anemia, or others idiopathic refractory cytopenias) who develop acute myeloid leukemia (AML) months or years later. In these syndromes, an abnormal bone marrow karyotype is found in about 50% cases, like in de novo AML. These abnormalities are similar to those observed in AML (mostly +8, -7, -5 or 5q-). The translocations t(8;21) and t(15;17) are never observed in preleukemia. Correlations exist between hematological data and cytogenetic features namely, in the 5q- syndrome. Thus in preleukemia the cytogenetic analysis is a valuable diagnostic method. At the present time, the prognostic value of the bone marrow karyotype is not clearly established but in single chromosome deletions (5q-, 20q-) the acute transformation is rare or delayed. At the opposite, evolution of the karyotype is generally regarded as a progression to high malignancy.

Anemia, Aplastic↗
PubMed2000

Fluorescence in situ hybridization (FISH) maps chromosomal homologies between the dusky titi and squirrel monkey.

The Platyrrhini are one of the most karyologically derived groups of primates and the evolution of their karyotypes is far from understood. The identification of the origin and direction of chromosome rearrangements will contribute to a better understanding of New World monkey phylogeny, taxonomy, and evolution. We mapped homology and identified translocations in the chromosomes of the dusky titi monkey (Callicebus moloch, 2n = 50) and the squirrel monkey (Saimiri sciureus, 2n = 44) by fluorescence in situ hybridization (FISH) of human chromosome paints. The hybridization results established chromosomal homologies between these New World primates, humans, other primates, and more distantly related mammalian species and show that both species have highly rearranged karyotypes. The total number of hybridization signals was 37 in C. moloch and 40 in S. sciureus, which is in the range of most comparisons of human chromosomes with phylogenetically more distant species outside of the primate order. Parsimony analyses of outgroup painting patterns allowed us to propose an ancestral karyotype for New World monkeys consisting of 2n = 56 with homologs to the following human chromosomes or chromosome segments: 1b; 1c; 2a; 2b; 3a; 3b; 3/21; 4; 5; 6; 7; 8a; 8/18; 9; 10a; 10/16; 11; 12; 13; 14/15; 15a; 16a; 17; 19; 20; 22; X; Y. Associations 8/18 and 10/16 are derived ancestral associations for all Platyrrhini. A 2/16 association found in S. sciureus and C. moloch was also seen in Ateles geoffroyi and Cebus capucinus; a 5/7 association in S. sciureus was present in A. geoffroyi, C. capucinus, and Alouatta belzebul. Other associations seen in the dusky titi monkey or the squirrel monkey are probably automorphisms. Comparison with chromosome phylogenies based on R-banding [Dutrillaux et al., 1986] showed that there were many errors in assigning homology with human chromosomes. The chromosomal phylogeny of New World monkeys based on banding patterns is in need of revision using modern molecular methods.

Animals↗