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 289 records · Page 16Linked to original sources
PubMed1982

Human large-bowel cancer: correlation of clinical and histopathological features with banded chromosomes.

Clinical and histopathological features were correlated with cytogenetic banding studies on direct preparations from 31 large-bowel tumors. An interesting relationship between the site and the karyotypes of the tumors was observed. There appears to be a progressive increase in chromosomal number and/or structural rearrangement as one progresses from proximal to distal large bowel. We suggest that these observations may be related to differences in function and micro-environment within different areas of the colon. Although it is not known what factors favor cytogenetic variability and instability on the left side or the presence of fewer abnormalities on the right side of the colon, it is evident that clonal karyotypic evolution may be important in the progression of large-bowel cancer. The brevity of follow-up precludes conclusions regarding the influence of karyotype on survival.

Cecal Neoplasms↗
PubMed1984

Heterochromatin and nucleolus-organizer-region behaviour at male pachytene of Sus scrofa domestica.

In the domestic pig (2n = 38) two types of constitutive heterochromatin can be differentiated by fluorescence counterstaining techniques. All 24 biarmed autosomes and the X chromosome have chromomycin A3-positive centromeric C-bands, whereas all 12 acrocentric chromosomes exhibit DA-DAPI-positive centromeric heterochromatin. Fluorescence analysis of male pachytene nuclei revealed that the DA-DAPI-positive C-bands form one or two large chromocentres per cell, while the chromomycin A3-bright C-material is well scattered. Hence, the bivalents formed by the acrocentric chromosome pairs are centromerically associated, whilst the submetacentric bivalents are not. Counce-Meyer spreading techniques were used to study the structure of synaptonemal complexes (SCs) both by light and electron microscopy. In general, the SCs of the domestic pig resemble those described for other mammals. The SC formed by the X and the Y may include up to 94.5% of the Y chromosome. In silver-stained microspreads each of the bivalents (nos. 8 and 10) bearing the nucleolus-organizer-regions (NORs) is connected to a pair of nucleoli, indicating that all four NORs are active during early meiotic stages. By contrast, in the majority of mitotic metaphases of phytohaemagglutinin-stimulated lymphocytes only one pair (no. 10) exhibited Ag-NOR staining. The significance of the chromosome disposition in the pachytene nucleus is discussed with regard to heterochromatin composition and karyotype evolution.

Animals↗
PubMed1978

Contributions to the karyology of Euconcocephalus incertus and Allodapia aliena (Tettigoniidae, Orthoptera.

The chromosome complement of two species of Indian Tettigoniids, namely, Euconcocephalus incertus (2n male = 20A + XX) and Allodapia aliena (2n female = 28A + XX) have been reported for the first time. The former species has two pairs of metacentric and two pairs of submetacentric autosomes, and a pair of metacentric sex chromosomes, whereas in the latter species all the chromosomes are telocentric and the sex chromosomes are very long. The probable occurrence of centric fusions, translocations and inversions during the karyotypic evolution of these grasshoppers is discussed.

Animals↗
PubMed1979

Clonal evolution of marker chromosomes in a case of myelofibrosis with myeloid metaplasia and myeloblastic transformation.

The diverse spectrum of acquired chromosome abnormalities in a female patient with myelofibrosis and myeloid metaplasia is described. A sequence of karyotypic evolution involving a ring chromosome is postulated. The terminal clinical picture was unusual in that there was obstructive renal failure from extramedullary myeloblastic transformation and infiltration of the bladder, and this was also present in other sites. Initially neutrophils showed low alkaline phosphatases activity but latterly two distinct populations in which cells had either high activity or none.

Alkaline Phosphatase↗
PubMed2004

Patterns of chromosome banding in four nabid species (Heteroptera, Cimicomorpha, Nabidae) with high chromosome number karyotypes.

Male Nabis (Aspilaspis) indicus (Stål), N. (A.) viridulus Spinola, Himacerus (Himacerus) mirmicoides (O. Costa) (2n=32+XY) and Prostemma guttula (Fabricius) (2n=26+XY) were studied using C-banding, silver nitrate staining and base-specific fluorochrome (DAPI and CMA(3)) staining. N. indicus differed from N. viridulus in distribution pattern of C-bands, which were telomeric in the former while interstitial in the latter. H. mirmicoides showed interstitial C-bands in the majority of autosomes. P. guttula had no conspicuous C-bands in other chromosomes, but only in the Y, which was totally heterochromatic. C-heterochromatin was labelled with DAPI, indicating that it was AT-rich. In every species, both X and Y chromosomes were NOR-bearing, and the NOR regions were GC-rich. In H.mirmicoides and P. guttula, NORs showed sub-median location in the X and distal in the Y, such a pattern being probably common in Nabidae. The present paper provides new information on the genome organization and new cytological markers useful for a better insight into karyotype evolution of nabid species.

Animals↗
PubMed1995

Chromosomal evolution and zoogeographic origin of southeast Asian shrews (genus Crocidura).

To the origins and evolution of Indomalayan shrews, we investigated the chromosomal variations of 14 species of Crocidura from SE Asia. Intraspecific polymorphism was mainly due to variation in the number of short chromosomal arms but C. lepidura and C. hutanis showed a polymorphism due to a centric fusion. The undifferentially stained karyotypes were similar in 9 species, all possessing 2n = 38 and FN = 54-56 (68); C. fuliginosa had 2n = 40 and FN = 54-58. These karyotypes are close to the presumed ancestral state for the genus Crocidura. Four species from Sulawesi had a reduced diploid number (2n = 30-34), a trend not observed among other SE Asian species but present in few Palaearctic taxa. Compared to the apparent stasis of karyotypic evolution observed among other SE Asian species, the high degree of interspecific differences reported among Sulawesian shrews is unusual and needs further investigation. Stasis and reduction in diploid number found in both Indomalayan and Palaeractic species suggest that these two groups share a common ancestry. This is in sharp contrast to most Afrotropical species which evolved towards higher diploid and fundamental numbers. The zoogeographical implications of these results are discussed.

Animals↗
PubMed1992

Comparative gene mapping in the species Muntiacus muntjac.

An extreme case of chromosomal evolution is presented by the two muntjac species Muntiacus muntjac (Indian muntjac, 2n = 6 [females], 7 [males]) and M. reevesi (Chinese muntjac, 2n = 46). Despite disparate karyotypes, these phenotypically similar species produce viable hybrid offspring, indicating a high degree of DNA-level conservation and genetic relatedness. As a first step toward development of a comparative gene map, several Indian muntjac homologs of known human type I anchor loci were mapped. Using flow-sorted, chromosome-specific Southern hybridization techniques, homologs of the protein kinase C beta polypeptide (PRKCB1) and the DNA repair genes ERCC2 and XRCC1 have been assigned to Indian muntjac chromosome 2. The male-specific ZFY gene was presumptively mapped to Indian muntjac chromosome Y2. Ultimate generation of a comparative physical map of both Indian and Chinese muntjac chromosomes will prove invaluable in the study of mammalian karyotype evolution.

Animals↗
PubMed1979

Mauritius type black rats with peculiar karyotypes derived from Robertsonian fission of small metacentrics.

All seventeen black rats collected from Mauritius Island were characterized by having many extra small acrocentric autosomes. Their basic karyotype was of Oceanian type, because of the presence of the large metacentric M1 and M2 pairs, but chromosome numbers in 13 specimens among them were 42, those of 3 specimens 43, and those of the remaining one specimen 44. Although the Oceanian type rat had 2 small acrocentric autosomes (pair no. 13), 16 Mauritius rats had 10 small acrocentrics, and the remaining one had 8 small acrocentrics. Comparative karyotype analysis between Oceanian and Mauritius type rats showed that the extra small acrocentrics found in Mauritius rats were due to Robertsonian fission of small metacentric pairs no. 14 and 18 of the original Oceanian type rat. Only one rat with 8 small acrocentrics showed the heteromorphic pair no. 18 consisting of one metacentric and two acrocentrics. The large metacentric M1 chromosome in 13 of 17 rats examined showed homologous pair, but two of them were heteromorphic by involving one metacentric M1 and two acrocentrics. In the remaining two rats M1 chromosome was not observed, but acrocentric pairs no. 4 and 7 were included. These acrocentrics were also suggested to be originated from Robertsonian fission of the large metacentric M1 chromosome. Robertsonian fission seemed to be one of the important mechanism found in karyotype evolution.

Animals↗
PubMed1987

Cytogenetic studies of human brain tumors and their clinical significance. II. Meningioma.

Cytogenetic study of 45 meningiomas from 31 female and 14 male patients are reported. No chromosomal abnormalities were found in nine (20%). These were predominantly meningotheliomatous, and were from younger patients (average age, 46 years). Monosomy 22 was noted in only 20% and in 12 patients (27%) with other losses and rearrangements. Among the latter, 50% were either recurrent or recurrent and invasive, the majority were fibromatous and occurred in older patients. Nonrandom loss was observed of the Y and abnormalities of chromosomes #1, #7, and #14 and, to a lesser extent, chromosomes #18, #19, and #20. Meningiomas may begin with no chromosomal abnormalities, having meningotheliomatous histopathologic appearance, occur in younger patients, and are less aggressive. Karyotypic evolution following loss of a chromosome #22 continues with losses and rearrangements of other chromosomes with apparent nonrandom involvement of chromosomes #1, #7, #14 and Y. This karyotypic change is associated with aggressive tumor behavior and fibromatous morphology.

Adult↗
PubMed2002

C-banded karyotypes of two Silene species with heteromorphic sex chromosomes.

Mitotic metaphase chromosomes of Silene latifolia (white campion) and Silene dioica (red campion) were studied and no substantial differences between the conventional karyotypes of these two species were detected. The classification of chromosomes into three distinct groups proposed for S. latifolia by Ciupercescu and colleagues was considered and discussed. Additionally, a new small satellite on the shorter arm of homobrachial chromosome 5 was found. Giemsa C-banded chromosomes of the two analysed species show many fixed and polymorphic heterochromatic bands, mainly distally and centromerically located. Our C-banding studies provided an opportunity to better characterize the sex chromosomes and some autosome types, and to detect differences between the two Silene karyotypes. It was shown that S. latifolia possesses a larger amount of polymorphic heterochromatin, especially of the centromeric type. The two Silene sex chromosomes are easily distinguishable not only by length or DNA amount differences but also by their Giemsa C-banding patterns. All Y chromosomes invariably show only one distally located band, and no other fixed or polymorphic bands on this chromosome were observed in either species. The X chromosomes possess two terminally located fixed bands, and some S. latifolia X chromosomes also have an extra-centric segment of variable length. The heterochromatin amount and distribution revealed by our Giemsa C-banding studies provide a clue to the problem of sex chromosome and karyotype evolution in these two closely related dioecious Silene species.

Chromosome Banding↗
PubMed1982

Genome evolution in pocket gophers (genus Thomomys). I. Heterochromatin variation and speciation potential.

A basic dichotomy exists in the amount and chromosomal position of constitutive heterochromatin (C-bands) in species of pocket gophers, genus Thomomys. Members of the "talpoides-group" of species (e.g., T. talpoides and T. monticola) have C-bands restricted to the centromeric regions. These taxa are characterized by Robertsonian patterns of karyotypic evolution. In contrast, species within the "bottae-group" are characterized by extensive amounts of heterochromatin, placed as whole-arm and apparent whole-chromosome (T. bottae) or as large interstitial blocks (T. umbrinus). These species are characterized by extensive non-Robertsonian variation in karyotype, variation which may be expressed from local population polymorphism to between population or species polytypy. Within T. bottae, the number of whole-arm heterochromatic autosomes is inversely proportional to the number of uniarmed chromosomes in the complement, which ranges from 0 to 36 across the species populations. In all-biarmed karyotypic populations, upward to 60 percent of the linear length of the genome is composed of heterochromatin. Populations with extensive heterochromatin variation and those with similar amounts meet and hybridize freely in nature. The implications of these date for current ideas on the function of heterochromatin, particularly as related to speciation models, are discussed.

Animals↗
PubMed1975

Variation of C-bands in the chromosomes of several subspecies of Rattus rattus.

All subspecies of black rats (Rattus rattus) used in the present study are characterized by having large and clear C-bands at the centromeric region. The appearance of the bands, however, is different in the subspecies. Chromosome pair No. 1 in Asian type black rats (2n=42), which are characterized by an acrocentric and subtelocentric polymorphism, showed C-band polymorphism. In Phillipine rats (R. rattus mindanensis) the pair was subtelocentric with C-bands, but in Malayan black rats (R. rattus diardii) it was usually acrocentric with C-bands. In Hong-Kong (R. rattus flavipectus) and Japanese black rats (R. rattus tanezumi) it was polymorphic with respect to the presence of acrocentrics with C-bands or subtelocentrics without C-bands. The other chromosomes pairs showed clear C-bands, but in Hong-Kong black rats the pairs No. 2 and 5 were polymorphic with and without C-bands. In Japanese black rats, 6 chromosome pairs (No. 3, 4, 7, 9, 11 and 13) were polymorphic in regard to presence and absence of C-bands, but the other 5 chromosome pairs (No. 2, 5, 6, 8 and 10) showed always absence of C-bands. Only pair No. 12 usually showed C-bands. C-bands in small metacentric pairs (No. 14 to 20) in Asian type black rats generally large in size, but those in the Oceanian (2n=38) and Ceylon type black rats (2n=40) were small. In the hybrids between Asian and Oceanian type rats, heteromorphic C-bands, one large and the other small, were observed. Based on the consideration of karyotype evolution in the black rats, the C-band is suggested to have a tendency toward the diminution as far as the related species are concerned.

Animals↗
PubMed2001

Physical locations of 5S and 18S-25S rDNA in Asian and American diploid Hordeum species with the I genome.

The physical locations of 5S and 18S-25S rDNA sequences in 15 diploid Hordeum species with the I genome were examined by double-target in situ hybridization with pTa71 (18S-25S rDNA) and pTa794 (5S rDNA) clones as probes. All the three Asian species had a species-specific rDNA pattern. In 12 American species studied, eight different rDNA types were found. The type reported previously in H. chilense (the 'chilense' type) was observed in eight American species. The chilense type had double 5S rDNA sites - two sites on one chromosome arm separated by a short distance - and two pairs of major 18S-25S rDNA sites on two pairs of satellite chromosomes. The other seven types found in American species were similar to the chilense type and could be derived from the chilense type through deletion, reduction or addition of a rDNA site. Intraspecific polymorphisms were observed in three American species. The overall similarity in rDNA patterns among American species indicates the close relationships between North and South American species and their derivation from a single ancestral source. The differences in the distribution patterns of 5S and 18S-25S rDNA between Asian and American species suggest differentiation between the I genomes of Asian and American species. The 5S and 18S-25S rDNA sites are useful chromosome markers for delimiting Asian species, but have limited value as a taxonomic character in American species. On the basis of rDNA patterns, karyotype evolution and phylogeny of the I-genome diploid species are discussed.

Americas↗
PubMed1995

[A cytogenetic study of four species of turtle from China].

The karyotypes, C-banding and Ag-NORs of four species of turtle from China have been studied. The results demonstrated that Cuora aurocapitata has 2n = 52(14M + 2SM + 4ST + 6T / 26m), NF = 72, 8 + 5 + 13(karyotypic formulae). Its secondary constrictions (SC) located on No. 1 p inter of group I; C. trifasciata has 2n = 52(12M + 4SM + 4ST + 6T + 26m), NF = 72, 8 + 5 + 13; Cistoclemmys flavomarginatus has 2n = 52(16M + 4ST + 6T + 26m), NF = 72, 8 + 5 + 13. The SC is also on No. 1 p inter of group I; C. galbinifrons has 2n = 52(16M + 2SM + 4ST + 6T + 24m), NF = 74, 9 + 5 + 12. Four pairs of SC of C. galbinifrons are on No. 1 p inter, No. 3,7 p par and No. 6(X chromosome) q per of group I. The heteromorphic chromosomes related with sexuelity were discovered in C. galbinifrons, while there is no that in other three species. All the centrometric regions of the chromosomes for the four studied species showed the various degree staining of C-positive. Only one homologous pair of Ag-NOR, is found for C. galbinifrons, which locate on No. 5 q per of group II. The Ag-NOR, of other three species lies in No. 7 q ter of group I. The mechanism of the karyotypic evolution is discussed. Individual evolutional mechanism of an heteromorphic sex pair of chromosomes.

Animals↗
PubMed2002

Distinct clinical outcomes for cytogenetic abnormalities evolving from aplastic anemia.

A serious complication of aplastic anemia (AA) is its evolution to clonal hematologic diseases such as myelodysplasia (MDS) and leukemia, which is usually associated with the appearance of a cytogenetic abnormality in bone marrow cells. We present here an analysis of a cohort of 30 patients with otherwise typical AA in whom clonal karyotypic evolution was observed during frequent periodic marrow examinations. The actuarial risk for this complication has been estimated in other studies at around 15% at 5 years. Conversion from normal to abnormal karyotype occurred at a constant rate after initial diagnosis, with about 50% of cases developing within the first 30 months. Transient chromosomal abnormalities were infrequent. Clinically, AA patients with clonal cytogenetic patterns were heterogenous; a variety of karyotypic defects with numerical and structural abnormalities of chromosome 7 accounted for 40% of all cases followed by trisomy 8, structural and numerical abnormalities of chromosome 13, deletion of Y chromosome, and complex cytogenetic abnormalities. Unlike in primary MDS, aberrancies of chromosome 5 and 20 were infrequent. The clinical course depended on the specific abnormal cytogenetic pattern. Most deaths related to leukemic transformation occurred in patients with abnormalities of chromosome 7 or complex cytogenetic alterations or both. Evolution of chromosome 7 abnormalities was seen most often in refractory patients who had failed to respond to therapy. In contrast, trisomy 8 developed in patients with good hematologic responses who often required chronic immunosuppression with cyclosporine A (CsA), and survival was excellent. Although AA patients with monosomy 7 showed a similar prognosis to those with primary MDS, trisomy 8 in AA appears to have a more favorable prognosis than in MDS.

Adolescent↗
PubMed1983

Cytogenetic study of 88 cases of refractory anemia.

Data obtained on 88 patients with refractory anemia or preleukemia, without previous cytotoxic treatment, showed medullar chromosomal abnormalities in 32%. In 45% of the cases, the disease had progressed to acute nonlymphocytic leukemia. A high frequency of acute transformation (78%) was observed in patients with abnormal clones. These results are different from those of the Second International Workshop on chromosomes in Leukemia. The discrepancies may be related to the difference between the cases selected for submission to the workshop and those of this study. Serial studies on 28 patients with abnormal karyotypes showed that two different populations of patients were investigated: one with a terminal smoldering phase of leukemia and the other with true preleukemic disease. In the latter group, no predictive karyotype evolution was seen.

Aged↗
PubMed1988

Stability of cytogenetic alterations in a human melanoma cell line and five clonal derivatives.

A cytogenetic study was done on a human malignant melanoma cell line and its 5 clones. Chromosome banding analysis indicated the presence of 7 "shared" markers (M) and 9 unique markers (m) that were present only in the clones. Chromosomes 1, 5, 9, 12, 17 and 21 were involved in M-markers and chromosomes 1, 2, 4, 6, 8, 9, 11, 16, 17, 18 and 21 were involved in m-marker formation. Both parental and clonal lines had near-triploid chromosome numbers. A number of M-markers were isochromosomes of the short (p) and long (q) arms of chromosome 1. Our cytogenetic data indicate that the parental line contained subpopulations of cells that were in different stages of karyotypic evolution.

Cell Line↗
PubMed1993

Chromosomal homologies between Drosophila lebanonensis and D. melanogaster determined by in situ hybridization.

Twelve biotin-labelled recombinant DNA probes were hybridized to polytene chromosomes of Drosophila melanogaster and D. lebanonensis. Probes were chosen in order to cover the whole chromosomal complement. Six probes correspond to known genes from D. melanogaster (RpII215, H3-H4, MHC, hsp28/23, hsp83, hsp70), four probes are clones isolated from a D. subobscura library (Xdh, lambda DsubS3, lambdaDsubG3, lambdaDsubG4) and the remaining two probes correspond to the Adh gene of D. lebanonensis and to one sequence (262), not yet characterized, from the same species. The chromosomal homologies obtained from the in situ hybridization results allow us to determine that Muller's C and D chromosomal elements are fused in the karyotype of D. lebanonensis and constitute the large metacentric chromosome. Single pericentric inversions in the E and B elements have generated the medium and small metacentric chromosomes, respectively. No great changes are detected in Muller's A element, which remains acrocentric. The changes detected in the karyotypic evolution of D. lebanonensis are frequently observed in Drosophila evolution, as deduced from chromosomal homologies of several Drosophila species. The results are also consistent with Muller's proposal that chromosomal elements have been conserved during the evolution of Drosophila.

Alcohol Dehydrogenase↗