Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “karyotype evolution”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,657 records · Page 92Linked to original sources
PubMed1980

Chromosome polymorphism in the Italian newt, Triturus italicus.

A chromosomal variation, changing shape and C-banding pattern of chromosome XII of Triturus italicus was detected among the offspring of two F1 hybrid families of T. italicus female x T. vulgaris meridionalis male. In both families a number of individuals appeared to have a metacentric instead of the expected subtelocentric chromosome XII of T. italicus.--Investigations in three well separated localities in the range of the species showed the polymorphism to have a wide distribution and to be part of a complex pattern involving at least two inversions and (presumably) deficiencies of large C-bands. At meiosis, the shape of bivalent XII, and the location and frequency of chiasmata in the bivalent varied with the karyomorph involved. It is suggested that large rearrangements may still play an important role in the karyological evolution of Triturus.

Animals↗
PubMed2000

Comparative chromosome map of the laboratory mouse and Chinese hamster defined by reciprocal chromosome painting.

Cross-species reciprocal chromosome painting was used to determine homologous chromosomal regions between the laboratory mouse and Chinese hamster. When mouse chromosome-specific paints were hybridized to Chinese hamster chromosomes, paints specific for mouse chromosomes 3, 4, 9, 14, 18, 19 and X each painted a single chromosomal region, whilst other mouse paints delineated multiple discrete chromosomal regions. The mouse Y paint produced non-specific signals on Chinese hamster chromosomes. Nineteen mouse autosome paints identified a total of 47 homologous chromosome regions in the genome of the Chinese hamster. Hybridization of Chinese hamster paints to mouse chromosomes not only confirmed the above results, but also identified which of the chromosomal regions of these two species were homologous. In total, 10 Chinese hamster autosomal paints detected 38 homologous autosomal segments in the mouse genome. A comparative chromosome map was established based on these reciprocal chromosome painting patterns. This map forms the basis for exchanging gene mapping information between the species and for studying genome evolution.

Animals↗
PubMed1999

A molecular cytogenetic analysis of the tribe Bovini (Artiodactyla: Bovidae: Bovinae) with an emphasis on sex chromosome morphology and NOR distribution.

Q-band comparisons were made among representative species of the four genera of the tribe Bovini (Bos, Bison, Bubalus, Syncerus) as well as to selected outgroup taxa representing the remaining two tribes of the subfamily Bovinae (nilgai, Boselaphini; eland, Tragelphini), the Bovidae subfamily Caprinae (domestic sheep) and the family Cervidae (sika deer and white-tailed deer). Extensive autosomal arm homologies were noted, but relatively few derivative character states were shared. Focus was then made on variation of the sex chromosomes and the chromosomal distribution of nucleolar organizer regions (NORs). Bovine BAC clones were used in molecular cytogenetic analyses to decipher rearrangements of the sex chromosomes, and a pocket gopher 28s ribosomal probe was used to map the chromosomal locations of nucleolar organizing regions (NORs). Some of the more noteworthy conclusions drawn from the comparative analysis were that: 1. The Bovidae ancestral X chromosome was probably acrocentric and similar to acrocentric X chromosomes of the Bovinae; 2. The domestic sheep acrocentric X is probably a derivative character state that unites non-Bovinae subfamilies; 3. Bos and Bison are united within the tribe Bovini by the presence of shared derivative submetacentric X chromosomes; 4. Sika and white-tailed deer X chromosomes differ by inversion from X chromosomes of the Bovinae; 5. The Bovini ancestral Y chromosome was probably a small acrocentric; 6. Bos taurus, B. gaurus and B. banteng share derivative metacentric Y chromosomes; 7. Syncerus and Bubalus are united by the acquisition of X-specific repetitive DNA sequence on their Y chromosomes; 8. Bovinae and Cervidae X chromosome centromere position varies without concomitant change in locus order. Preliminary data indicate that a knowledge of the chromosomal distribution of NORs among the Bovidae will prove to be phylogenetically informative.

Animals↗
PubMed1988

Does heterochromatin variation potentiate speciation? A study in Nesokia.

An increasing incidence of sex-chromosome variation in constitutive heterochromatin, including individuals with mosaic genotypes, has been observed in a single natural population of Nesokia indica, the Indian mole rat. Variations in the heterochromatic areas of the X chromosome are largely due to deletions at R-band-positive regions corresponding to folate-sensitive fragile sites. All individuals with either a pre- or post-zygotic loss or gain of sex-chromosome heterochromatin have so far proved to be infertile. Whether such F1 sterility is due to abnormal gonadal development, gametic incompetence, or other factors is not clear. More important is the indication that the constitutive heterochromatin of this species may contain coding DNA sequences with putative regulatory functions.

Animals↗
PubMed2000

Leukemia relapse reconsidered from the molecular aspect.

Relapse, a major obstacle in the treatment of acute leukemia, is essentially caused by re-growth of residual leukemia cells, frequently accompanied by resistance to chemotherapy. Comparative studies of clones both at initial diagnosis and at subsequent relapse have indicated that phenotype and karyotype are frequently changed at relapse. This can be recognized as the result of negative selection by chemotherapy in a heterogeneous population. Furthermore, complex molecular alterations that include the loss of as well as the acquisition of mutations are noticed by comparing multiple genes associated with leukemia, suggesting a continuous genetic evolution. Studies on leukemia relapse have thus served as a model of clonal progression, which can be serially observed, including selection by chemotherapy, induction of resistant phenotype, and genetic alteration.

Antineoplastic Agents↗
PubMed2001

Clonal evolution of a radon-induced rat lung tumor.

Radon gas may represent a source of pulmonary radio-contamination either in mine or in domestic conditions. Since epidemiological studies are controversial, as long as biological markers of the exposure to such agents will not be identified, the question will remain open. We have previously shown a direct dose-dependent relationship between lung cancer occurrence and radon inhalation of rats. In this study, we report a cytogenetic study of a radon-induced rat lung tumor. Chromosome banding and chromosome specific paintings were performed on cultures of both fresh and xenografted tumors. We found by analyzing 17 sub-clones that all karyotypes presented a translocation involving rat chromosomes (RNO) 8 and 20, and a terminal deletion of RNO 15p suggesting a monoclonal origin of this tumor. RNO 15 is homologous to numerous human chromosomes (HSA), in particular to HSA 3p14.2, 3p22-p24.1 and 3p24.2-p24.3, this human chromosome being frequently lost in human lung carcinomas. Besides sharing chromosome alteration involving common features with those found in human lung cancer, this rat lung carcinoma represents a useful model to study tumor progression with respect to clonal evolution.

Animals↗
PubMed2003

Aneuploidy in carcinomas may be initiated by the acquisition of a single trisomy.

Karyotypic studies of eight endometrioid carcinomas of the endometrium in this laboratory, four colorectal polyps (from this laboratory or reported in the literature), and four early carcinomas of the ovary (from the literature), provide evidence that clonal evolution leading to malignant neoplasms at these sites originates when a cell acquires a single additional chromosome. In different tumors, different chromosomes may be involved in this change from euploidy to aneuploidy. Since the resultant clones of trisomic cells occur at an early stage of tumor development, their presence is only likely to be determined when they are at a location that is accessible for study. As aneuploidy is a virtually constant feature of malignancy, the possibility that the concept of a single trisomy as the initial event in the development of all malignant solid neoplasias should be addressed.

Aged↗
PubMed1988

An identical t(Y;1)(q12;q21) in two patients with myelodysplastic syndromes.

Two male patients with myelodysplastic syndromes, one with refractory anemia with excess blasts (RAEB), the other with chronic myelomonocytic leukemia both had in their bone marrow and peripheral blood cells the same abnormal karyotype 46,X,-Y, + der (Y)t(Y;1)(q12;q21). This abnormality produced trisomy for the 1q21-1qter region of chromosome 1. In addition to the t(Y;1), the patient with RAEB had a del(20)(q11) abnormality in separate CFU-GM and BFUe progenitor cell populations. The t(Y;1) clone of this patient underwent chromosomal evolution with the acquisition of trisomies for chromosomes 2, 6, 8, and 9. Cytogenetic analysis of serial peripheral blood samples showed that the t(Y;1) clone and its derivatives gradually replaced that with the 20q- abnormality. Metaphase cells trisomic for chromosomes 2, 6, 8, and 9 were found predominantly in the CFU-GM population and only rarely in BFUe colonies, suggesting that chromosomal evolution was largely confined to the granulocytic lineage.

Aged↗
PubMed1989

Spontaneous resolution of fetal cystic hygroma and hydrops in Turner syndrome.

On a routine ultrasound examination, a cystic hygroma and hydrops were noted at 21 weeks' gestation in a fetus with a 45,X karyotype. Serial studies demonstrated a marked reduction in the size of the cystic hygroma and complete resolution of ascites. At birth, the term infant had features characteristic of the Turner syndrome, including a webbed neck. A critical coarctation of the aorta required repair in the neonatal period. Our case provides glimpses of the intrauterine evolution of the Turner phenotype. We suggest that the possibility of survival when such lesions are detected prenatally may be greater than previously thought.

Adult↗
PubMed1975

[Comparison of the karyotype of the orangutan (Pongo pygmaeus) to those of man, chimpazee, and gorilla].

Various banding thechniques were employed to compare the karyotype of the Orang-utan (Pongo pygmaeus) with those of Man, the Chimpanzee, and the Gorilla. The following was concluded: 1) Almost all the bands are common, their analogy being close to 99%. The four species derive, therefore, from a common ancestor. The rearrangements which occurred during evolution were generally balanced; 2) The analysis of rearrangements shows that the Orang-utan, then the Gorilla, then the Chimpanzee, and lastly Man were derived in that order from the common stemline.

Animals↗
PubMed2005

Persistence of various chromosomal aberrations in recipient cells during complete remission after bone marrow transplantation followed by graft rejection.

A 16-year-old boy in a second remission of acute lymphoblastic leukemia (ALL) had undergone transplantation of bone marrow from an unrelated donor. The conditioning regimen consisted of high-dose cytarabine, etoposide and 12 Gy of total-body irradiation. Although the donor marrow was rejected, hematopoiesis by the recipient himself recovered and he has remained in complete remission for more than 8 years after stem cell transplantation (SCT). Bone marrow karyotype analysis 1 month after SCT showed random chromosomal aberrations. Although complete remission was maintained, various chromosomal aberrations were detected in marrow cells, and in peripheral blood cells under phytohemagglutinin stimulation over 8 years. Moreover, a clone including del(20)(q11) appeared in marrow cells 7 months after SCT and thereafter was also detected 5 years later in the peripheral blood. This persistence of various chromosomal aberrations and a stable clone without evolution to myelodysplastic syndrome or leukemia support the multi step theory of leukemogenesis.

Adolescent↗
PubMed1983

Chromosome and C-heterochromatin polymorphisms in the Italian newt, Triturus italicus.

A combined chromosome and C-heterochromatin polymorphism in pair 12 in the complement of the newt species, T. italicus is described. The C-heterochromatin polymorphism is presumably due to a loss in the proximal C-band, whereas the chromosomal polymorphism has its origin in two different independent pericentric inversions both including the centromere and the proximal C-band of chromosome 12. The double-inversion polymorphism has a wide distribution over the range and follows a clear bipolarity between a northern area where the karyotype is homomorphic for the standard type of pair 12 (ST/ST) and an opposite area where the ST type is completely replaced by variant M1 and M2 metacentric chromosomes 12. Various karyophylogenies are possible, but the simplest and the most probable presumes an ancestral karyotype of ST/ST and a mechanism of gradual replacement of the heterobrachial chromosome ST by two independent pericentric inversions. The present data are discussed in relation to existing theories on karyological evolution of Urodeles and the functional significance of telocentric chromosomes suggested by Sessions et al. (1982).

Animals↗
PubMed2001

Burkitt's acute lymphoblastic leukaemia transformation after myelodysplastic syndrome.

We describe a patient with myelodysplastic syndrome (MDS) that transformed to Burkitt's acute lymphoblastic leukaemia (ALL). The leukaemic blasts were negative for peroxidase staining, and expressed CD10, CD19, CD22, CD38, human leucocyte antigen (HLA)-DR and surface immunoglobulin (sIg) M, but neither sIgD nor sIgG were expressed. Chromosomal study during the ALL phase showed t(8;22)(q24;q11) in addition to the karyotypes determined during the MDS phase. Furthermore, overexpression of c-myc mRNA was confirmed in ALL blasts. These findings indicate that MDS transformed to Burkitt's ALL through multiple cytogenetic evolutions, the final event of which seems to be overexpression of the c-myc gene.

Acute Disease↗
PubMed1997

Strain-relatedness among different populations of the pathogenic yeast Candida albicans analyzed by DNA-based typing methods.

A pathogenic yeast Candida albicans is one of the most frequently isolated microorganisms in patients suffering from opportunistic infection. The typing of the isolates is important not only to elucidate the route of infection but to explore the evolution of the pathogenic yeast. This article presents an overview of recent research on the strain typing in different populations of C. albicans using the following DNA-based methods: electrophoretic karyotyping by pulsed field gel electrophoresis (PFGE), restriction fragment length polymorphism (RFLP) of digests of genomic DNA by restriction enzymes (with or without Southern hybridization with a DNA probe) and amplification of random or specific sequences by using polymerase chain reaction (PCR). The results of these methods were compared for strain discrimination. Studies on the genetic diversity of the strains among different individuals in a single population cohort, and among different populations of healthy carriers and immunocompetent and immunocompromised patients, were reviewed. Typing of the strains recurrently isolated through the episodes of diseases such as vaginitis and AIDS revealed the occurrence of strain variation or microevolution. Typing of isolates from nosocomial infections indicated the possible occurrence of horizontal transmission of the disease within a single hospital. In addition, recent studies suggested a possible mechanism that might involve the C. albicans-specific repetitive sequences, RPSs, for chromosome rearrangements leading to strain variation.

Candida albicans↗
PubMed1982

Structural anomalies of the X chromosome: personal observation and review of non-mosaic cases.

We describe a new case of partial deletion of the long arm of the X chromosome, found in a 24-year-old female with secondary amenorrhea; the karyotype of the proposita is 46,X,del(X)(q22). We take this opportunity to review the previously published descriptions of non-mosaic structural anomalies of the X chromosome (X isochromosomes excepted) with the goal of "testing" the recent hypothesis formulated about: (a) the existence of an X inactivation center (Therman et al. 1974b); (b) the presence of a "b" segment remaining active on Xp (Therman et al. 1976); (c) the potential importance of a critical area on Xq linked to gonadal function (Sarto et al. 1973); and (d) the presence of normal gonadal function despite and Xp terminal deletion (Fraccaro et al. 1977). We conclude that the above-mentioned theories, as well as those concerning phylogenetic evolution of sex chromosome morphology presented by Lyon (1974) and Hoo (1975), receive support from practically all of the 149 cases we compared. Regarding the features of the Turner syndrome, we propose "mapping" of the X chromosome as follows: the genes involved in gonadal function seem to be located on the proximal part of Xp and on the distal part of Xq, whereas the genes whose absence is responsible for somatic features of the syndrome may be distributed along the length of Xp and the middle section of Xq(q21-q26). Furthermore, we note some interesting analogies between the evolutional model proposed by Hoo (1975) and the map we visualize.

Adult↗
PubMed2000

Spectral karyotyping (SKY) refinement of a complex karyotype with t(20;21) in a Ph-positive CML patient submitted to peripheral blood stem cell transplantation.

A patient with a Ph-positive chronic myeloid leukaemia (CML) was submitted to allogeneic peripheral blood stem cell transplantation from an HLA-haploidentical related donor 7 years after the diagnosis. Six months later, he showed a disease relapse while cytogenetic analysis displayed a complex karyotype. To characterise the chromosomal rearrangements spectral karyotype (SKY) analysis was used. This redefined all chromosome rearrangements and revealed a t(20;21)(q11;q22). FISH analysis with a specific probe for the AML1 gene disclosed disruption of this gene which was partially translocated on to the long arm of chromosome 20. It is likely that this rearrangement, unusual for CML, was implicated in the disease evolution towards blastic crisis (BC).

Adult↗