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 469 records · Page 26Linked to original sources
PubMed1990

Chromosomal localization and copy number of 18S + 28S ribosomal RNA genes in evolutionarily diverse mosquitoes (Diptera, Culicidae).

In situ hybridization using 3H-labeled 18S and 28S ribosomal DNA (rDNA) probes from Aedes albopictus was performed on the mitotic chromosomes of 20 species of mosquitoes belonging to 8 genera of subfamilies Culicinae and Anophelinae. In all but one species examined, the rDNA family was localized to a single chromosome per haploid genome. Aedes triseriatus was the only exception, with the rDNA cistrons present on chromosome 1 and on chromosome 3. The ribosomal RNA genes were located on chromosome 1 in Ae. albopictus, Ae. aegypti, Ae. flavopictus, Ae. seatoi, A. polynesiensis, Ae. alcasidi, Ae. annandalei, Ae. mascarensis, Ae. hendersoni, Ae. atropalpus, Ae. epactius, Culex pipiens quinquefasciatus, Wyeomyia smithii, and Sabethes cyaneus; chromosome 2 in Ae. mediovittatus and Haemagogus equinus; chromosome 3 in Armigeres subalbatus and Tripteroides bambusa; and the heteromorphic X and Y chromosomes in Anopheles quadrimaculatus. The variation in the location of ribosomal RNA genes on the different chromosomes and at different positions on the chromosome arm among the mosquito species examined is suggestive of considerable chromosome repatterning through translocations and inversions in the karyotypic evolution of mosquitoes. Dot-blot hybridization was used to estimate copy number of rRNA genes; the copy number per haploid genome ranged from 39 +/- 3.27 in Sa. cyaneus to 1023 +/- 68.14 in Ae. flavopictus.

Animals↗
PubMed1991

Characterisation of a tandem repetitive sequence cloned from the deer Capreolus capreolus and its chromosomal localisation in two muntjac species.

The isolation and characterisation of a highly repetitive DNA sequence from the genome of the Roe deer Capreolus capreolus is reported. This sequence is characterised by tandem repetition and located within centric heterochromatin as demonstrated by non isotopic in situ hybridisation to the karyotypes of the Indian and Chinese muntjacs. Amplification and/or clustering of these sequences during the drastic karyotype evolution of the genus Muntiacus was noted in the large centromere of the X chromosome of the Indian muntjac. Partial sequence analysis revealed a 62% sequence homology with the sat 1A sequences of Muntiacus muntjak vaginalis.

Animals↗
PubMed2000

Comparative FISH mapping of bovid X chromosomes reveals homologies and divergences between the subfamilies bovinae and caprinae.

Comparative FISH mapping of river buffalo (Bubalus bubalis, BBU), sheep (Ovis aries, OAR), and cattle (Bos taurus, BTA) X chromosomes revealed homologies and divergences between the X chromosomes in the subfamilies Bovinae and Caprinae. Twenty-four and 17 loci were assigned for the first time to BBU X and OAR X, respectively, noticeably extending the physical map in these two species. Seventeen loci (four of which for the first time) were also FISH mapped to BTA X and used for comparative mapping studies on the three species, which show three morphologically different X chromosomes: an acrocentric (BBU X), an acrocentric with distinct short arms (OAR X), and a submetacentric (BTA X). The same order of loci were found on BTA X and BBU X, suggesting that a centromere transposition, with loss (cattle) or acquisition (river buffalo) of constitutive heterochromatin, differentiated the X chromosomes of these two bovids. Comparison of bovine (cattle and river buffalo) and caprine (sheep) X chromosomes revealed at least five common chromosome segments, suggesting that multiple transpositions, with retention or loss of constitutive heterochromatin, had occurred during their karyotypic evolution.

Animals↗
PubMed2001

Chromosomal distribution of the telomere sequence (TTAGGG)(n) in the Equidae.

Telomeres are a class of repetitive DNA sequences that are located at chromosome termini and that act to stabilize the chromosome ends. The rapid karyotypic evolution of the genus Equus has given rise to ten taxa, all with different diploid chromosome numbers. Using fluorescence in situ hybridization (FISH) we localized the mammalian telomere sequence, (TTAGGG)(n), to the chromosomes of nine equid taxa. TTAGGG signal was located at chromosome termini in all species, however additional signal was seen at interstitial sites on some chromosomes in the Burchell's zebra, Equus quagga burchelli, the Hartmann's zebra, Equus zebra hartmannae, and at large heterochromatin-associated regions on the chromosomes of the donkey, Equus asinus. The interstitial signal in the zebras may be a relic of an ancient telomere-telomere fusion and mark the point at which two ancestral chromosomes may have fused. For the donkey, the heterochromatin-associated signal may represent degenerate telomere-like satellite sequences and identify a second type of satellite DNA for this taxon.

Animals↗
PubMed2004

Gene mapping of 5S rDNA sites in eight fish species from the Paraíba do Sul river basin, Brazil.

The use of improved cytogenetic techniques such as fluorescent in situ hybridization (FISH) has offered important methodologies for cytotaxonomic and evolutionary studies. In particular, the mapping of 5S rDNA sites has proved to be an excellent marker in the study of different organisms and, more recently, in fish. In the present work, the FISH technique was used to map the 5S rDNA sites in the chromosomes of eight neotropical fish species from the Paraíba do Sul river basin, four of these belonging to the order Characiformes, family Characidae, genus Astyanax (A. scabripinnis, A. parahybae, A. giton and A. intermedius) and four to the order Siluriformes, family Loricariidae (Neoplecostomus microps, Harttia loricariformis, Hypostomus affinis and Upsilodus sp.). Karyotype evolution aspects of the analyzed groups are discussed.

Animals↗
PubMed2004

B chromosomes and Robertsonian fusions of Dichroplus pratensis (Acrididae): intraspecific support for the centromeric drive theory.

We tested the centromeric drive theory of karyotypic evolution in the grasshopper Dichroplus pratensis, which is simultaneously polymorphic for eight Robertsonian fusions and two classes of B chromosomes. A logistic regression analysis performed on 53 natural populations from Argentina revealed that B chromosomes are more probably found in populations with a higher proportion of acrocentric chromosomes, as the theory predicts. Furthermore, frequencies of B-carrying individuals are significantly negatively correlated with the mean frequency of different Robertsonian fusions per individual. No significant correlations between presence/absence or frequency of Bs, and latitude or altitude of the sampled populations, were found. We thus provide the first intraspecific evidence supporting the centromeric drive theory in relation to the establishment of B chromosomes in natural populations.

Animals↗
PubMed2005

The impact of chromosome sorting and painting on the comparative analysis of primate genomes.

Chromosome sorting by flow cytometry is the main source of chromosome-specific DNA for the production of painting probes. These probes have been used for cross-species in situ hybridization in the construction of comparative maps, in the study of karyotype evolution and phylogenetics, in delineating territories in interphase nuclei, and in the analysis of chromosome breakpoints. We review here the contributions that this technology has made to the analysis of primate genomes.

Animals↗
PubMed2006

Chromosomal distribution and organization of three cervid satellite DNAs in Chinese water deer (Hydropotes inermis).

The species-specific profile and centromeric heterochromatin localization of satellite DNA in mammalian genomes imply that satellite DNA may play an important role in mammalian karyotype evolution and speciation. A satellite III DNA family, CCsatIII was thought to be specific to roe deer (Capreolus capreolus). In this study, however, this satellite DNA family was found also to exist in Chinese water deer (Hydropotes inermis) by PCR-Southern screening. A satellite III DNA element of this species was then generated from PCR-cloning by amplifying this satellite element using primer sequences from the roe deer satellite III clone (CCsatIII). The newly generated satellite III DNA along with previously obtained satellite I and II DNA clones were used as probes for FISH studies to investigate the genomic distribution and organization of these three satellite DNA families in centromeric heterochromatin regions of Chinese water deer chromosomes. Satellite I and II DNA were observed in the pericentric/centric regions of all chromosomes, whereas satellite III was distributed on 38 out of 70 chromosomes. The distribution and orientation of satellite DNAs I, II and III in the centromeric heterochromatin regions of the genome were further classified into four different types. The existence of a Capreolus-like satellite III in Chinese water deer implies that satellite III is not specific to the genus Capreolus (Buntjer et al., 1998) and supports the molecular phylogeny classification of Randi et al. (1998) which suggests that Chinese water deer and roe deer are closely related.

Animals↗
PubMed1977

Chromosomes of Peromyscus (rodentia, cricetidae). VI. The genomic size.

In the genus Peromyscus cells of all species contain 48 chromosomes; however, the fundamental number varies from 56 (P. Crinitus, P. boylei) to 96 (P. eremicus). In some cases biarmed chromosomes are the result of pericentric inversions, while in others they are the result of addition of large amounts of constitutive heterochromatin. Flow microfluorometric DNA-per-cell determinations demonstrated that in some species (P. eremicus) the genome is increased by 36% over the amount of DNA found in most mammalian species. Studies of unique karyotypes with increased amounts of DNA added as constitutive heterochromatin may ultimately help in the elucidation of the mechanisms involved in karyotype evolution and speciation.

Animals↗
PubMed1978

Cytogenetic aspects of phylogeny in the Bovidae. II. C-banding.

Constitutive heterochromatin in the Bovidae, as revealed by C-banding, was mostly located in the centromeric regions. Considerable variation was, however, evident in the size of the C-bands both within and between subfamilies. Some evidence was found for a reduction in the amount of centromeric heterochromatin in bi-armed relative to acrocentric autosomes, and these findings are discussed in relation to karyotype evolution in the group.

Animals↗
PubMed1993

Cytogenetic characterization of the AS cell line derived from the Atlantic salmon (Salmo salar L.).

The chromosome complement of the fish cell line AS, derived from the Atlantic salmon (Salmo salar L., 2N = 58), was investigated by C-, Ag-NOR, restriction endonuclease, and BrdU-replication banding. The cell line has a modal chromosome number of 52 with a fixed number of chromosomal rearrangements. The variety of banding patterns obtained allowed us to identify three chromosome markers in the cell line. The identification of their possible origin and significance in karyotype evolution are discussed.

Animals↗
PubMed1994

Localization of the telomeric (TTAGGG)n sequence in chicken (Gallus domesticus) chromosomes.

The distribution of the highly conserved eukaryotic telomeric (TTAGGG)n sequence was investigated in chicken metaphase chromosomes using the FISH technique. Besides the expected telomeric locations, interstitial as well as centromeric locations of the (TTAGGG)n repeat were observed on several macrochromosomes. The microchromosomes display three discrete patterns of labeling with this repeat. The significance of this extreme-different distribution of the telomeric related sequence in chicken chromosomes may lie in pointing to structural events that might have occurred during the process of karyotype evolution.

Animals↗
PubMed1996

A stable marker chromosome with a cryptic centromere: evidence for centromeric sequences associated with an inverted duplication.

Centromere activation, an important mechanism in karyotype evolution, is occasionally observed in some human chromosome rearrangements. We report a possible occurrence of centromere activation in a marker chromosome containing an atypical centromere associated with an inverted duplication of the region 14q32 --> qter. The marker chromosome's reduced centromere lacks both the alpha and beta satellite sequences usually found at normal centromeres. In an attempt to identify the centromeric sequences, the marker chromosome was flow-sorted and amplified by a degenerate oligonucleotide primer polymerase chain reaction. Reverse chromosome painting experiments showed that the marker chromosome contains sequences that are unique to the distal region of chromosome 14, as well as a low copy number of (centromeric) sequences that are also highly represented in the centromeres of chromosomes 18 and 19. These data suggest the activation of a novel centromere in the 14q32 --> qter region, very likely consequent to the duplication of the region itself.

Adult↗
PubMed1997

Instability of CHO chromosomes containing interstitial telomeric sequences originating from Chinese hamster chromosome 10.

We identified a marker chromosome in the CHO K1 cell line containing amplifications of interstitial telomeric sequences originating from Chinese hamster chromosome 10. Analysis of the progression of this chromosome in two subclones of CHO K1 revealed sensitivity of one amplicon to chromosome breakage, resulting in telomere function at the break site. In addition, two more marker chromosomes, both containing amplifications of interstitial telomeric sequences from chromosome 10, were formed during karyotypic evolution of the CHO K1 subclones. The presence of some of the marker chromosomes was also identified in the radiosensitive xrs 5 cell line derived from CHO K1. These results indicate instability of CHO K1 chromosomes containing interstitial telomeric sequences originating from Chinese hamster chromosome 10.

Animals↗
PubMed2004

Leukemic transformation in myelofibrosis with myeloid metaplasia: a single-institution experience with 91 cases.

Among 2333 consecutive patients with myelofibrosis with myeloid metaplasia (MMM) seen at our institution, 91 fulfilled the World Health Organization (WHO) criteria for leukemic transformation (LT). All episodes of LT were myeloid in origin (acute myeloid leukemia [AML]) with all French-American-British (FAB) subtypes represented except M3; the most frequent subtypes were M7 (25.4%), M0 (22.4%), and M2 (17.9%). Cytogenetic studies during LT were available in 56 patients and revealed a clonal abnormality in 51 (91%): 30 patients had complex karyotype, 2 had core-binding factor gene lesions, and 18 had abnormalities of chromosome 5 or 7. Karyotypic evolution was documented in the majority of the patients in whom serial analysis was possible. In general, LT was fatal in 98% of the cases after a median of 2.6 months (range, 0-24.2 months). Twenty-four patients received AML-like induction chemotherapy that resulted in no complete remission: 41% reverted into chronic-phase disease and the incidence of treatment-related mortality was 33%. The remaining 67 patients received either supportive care alone (48 patients) or low-intensity chemotherapy (19 patients). Overall, survival was similarly poor in all 3 treatment categories. The outcome of LT in MMM with current therapies is dismal and either supportive care alone or appropriate clinical trials should be considered.

Adult↗
PubMed2006

Application of yeast artificial chromosomes in fluorescence in situ hybridization.

In addition to the well-known applications of yeast artificial chromosomes (YACs) in classical molecular genetics, they also are used for molecular cytogenetic studies. YACs, as well as other locus-specific probes like DNA, plasmids, cosmids, P1-clones, or bacterial artificial chromosomes can be labeled with fluorochromes and applied in fluorescence in situ hybridization (FISH) experiments. Various applications are possible, such as gene mapping, FISH banding, determination of chromosomal breakpoints, characterization of derivative chromosomes, studies on the interphase architecture, or karyotypic evolution studies. This chapter outlines the basic principle of how YACs can be hybridized in situ on chromosome preparations. Moreover, an overview is given on possible questions to be processed using YACs as FISH probes.

Chromosome Mapping↗
PubMed2000

Protection of human tumor cells of differing radiosensitivity by WR-1065.

We examined the ability of WR-1065, the biologically active aminothiol form of the clinically used drug amifostine (WR-2721, Ethyol), to protect cultures of two human glioblastoma cell lines of greatly differing radiosensitivity from the cytotoxic effects of gamma radiation. M059J cells are extremely radiosensitive compared to M059K cells (which were derived from the same tumor) and are defective in the DNA-dependent protein kinase (DNAPK)-mediated pathway for the repair of DSBs. In spite of their marked phenotypic differences, the two glioblastoma lines were protected equivalently ( approximately 1.8-fold) after a 30-min preirradiation treatment with 4 mM WR-1065. These findings are in agreement with earlier studies that showed no relationship between the ability of another aminothiol, cysteamine, to protect human tumor cells with differing abilities to repair DSBs and/or radiosensitivity. Thus it appears that differences in intrinsic radiosensitivity and ability to repair DSBs are not important general factors in the modulation of the radiosensitivity of human cells by aminothiols. Because of a previous report that the radiosensitive mutant rodent xrs5 cell line (which, like M059J, is defective in the DNAPK-mediated pathway for repairing DSBs) is unusually refractory to the radioprotective effects of WR-1065, we re-examined the ability of WR-1065 to protect these cells. In contrast to the earlier studies, both the wild-type and mutant rodent lines were protected extensively by WR-1065. This discrepancy might be related to some unknown factor, such as differences in chromatin organization among xrs5 subclones that arise during their karyotypic evolution, possibly leading to altered DNA-drug associations.

Animals↗