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At least 613 records · Page 34Linked to original sources
PubMed1990

Chromosome analysis of 31 Wilms' tumors.

Cytogenetic analysis was done on 31 Wilms' tumors, including 2 renal tumors of clear cell sarcoma type, using short term cultures of primary tumors and/or nude mouse passages. Nonrandom secondary chromosome abnormalities, in particular, were noted as evidence of clonal evolution. Apparently normal karyotypes were found in 5 Wilms' tumors, all in patients less than or equal to 22 months old, and in one clear cell sarcoma. Abnormal karyotypes were seen in 25 tumors (80%); 6 were pseudodiploid, 3 were hypodiploid, and 16 (52%) were hyperdiploid, of which 8 had a modal number of 47-49 and 8 had a modal number of 50-55. Nonrandom structural abnormalities involved 1p/1q, 11p, 7p/7q, 16p/16q, 12q, and 17p/17q. Nonrandom numerical abnormalities included +6, +8, and +18. Trisomy 12 was the most common abnormality, structural or numerical, seen in 52% of tumors (81% of the hyperdiploid). In 2 tumors the +12 was the only apparent abnormality; in 1 other tumor an i(12q) was seen, suggesting that +12 may have special significance in the clonal progression of Wilms' tumor. Informative karyotypes of 68 Wilms' tumors from other reports were reviewed and compared to results in this series.

Child↗
PubMed1982

Trisomy 15 and other nonrandom chromosome changes in Rauscher murine leukemia virus-induced leukemia cell lines.

The cytogenetics of Rauscher murine leukemia virus-induced erythroid, myeloid, and lymphatic leukemias were studied in BALB/c and DBA/2 mice. In primary virus-induced leukemias, no chromosome abnormalities were found. However, in tumors derived from transplanted leukemia tissue and in cell lines obtained from these tumors, euploidy and mostly aneuploidy were observed that varied according to the type of tumor cells and the number of passages. Eleven erythroleukemia cell lines showed aneuploidy from the first in vivo transplant stage on. Nonrandom abnormalities were found: trisomy 15 in 9 of 11 lines, followed by trisomy 3 in 8 of 11 lines and monosomy 6 in 5 of 11 lines. Subsequent evolution of the karyotypes was frequent (10 of 11 lines) and rapid. In vivo cell lines established from these tumors showed many structural rearrangements. Three myeloid lines revealed a stable karyotype with no or only minor changes: trisomy 15 in 1 line and normal diploid in 2 lines. One lymphatic leukemia cell line established in vitro presented with a very stable karyotype: trisomies 14 and 15. Another in vivo transplantable line showed trisomies 11, 9, and 17. These results suggest that trisomy of chromosome 15 plays a significant role in tumors derived from different types of mouse leukemias.

Aneuploidy↗
PubMedDate not supplied

[Value of karyotype in vascular acrosyndromes].

The evolution of Raynaud's phenomenon may, when clinical manifestations and capillaroscopy evoke the diagnosis of systemic disease, cause to consider performing a karyotype. In these cases, abnormalities are frequent, and 10% of these abnormalities must cause to suspect a collagen disease. The presence of the breaking factor is not the only etiology of these frequent abnormalities and a very thorough investigation must be made in order to rule out an extrinsic or idiopathic cause. Difficult to perform, it requires a highly specialized laboratory and demonstrates all its advantages in the etiological diagnosis of Raynaud's phenomenon.

Capillaries↗
PubMed2002

Cytogenetic and molecular genetic aspects of idiopathic myelofibrosis.

Idiopathic myelofibrosis is a chronic myeloproliferative disorder in which the characteristic fibroblast proliferation is thought to be a secondary phenomenon resulting from the inappropriate release of megakaryocyte- and/or monocyte-derived growth factors, including PDGF, TGF-beta, bFGF and calmodulin. In contrast, the haematopoietic cells are clonal, although the underlying pathogenetic mechanisms remain essentially unknown. Cytogenetic studies have highlighted that 13q-, 20q-, +8 and abnormalities of chromosomes 1, 7 and 9 constitute more than 80% of the chromosomal changes. A third of idiopathic myelofibrosis cases have abnormal karyotypes at diagnosis, a figure that increases if follow-up analyses are performed. Evolution to more complex karyotypes may accompany clinical progression, with abnormalities increasing to around 90% following acute leukaemic transformation. Cytogenetic abnormalities have been associated with prognosis and to a lack of treatment response to androgens. Oncogene mutations are rare and include point mutations in N-RAS, c-KIT and TP53.

Chromosome Aberrations↗
PubMed1984

Molecular probes of phylogeny and biogeography in toads of the widespread genus Bufo.

Genetic relationships among 25 species of Central and South American Bufo and among representative North, Central, and South American, Asian, and African Bufo were probed, using the quantitative immunological technique of microcomplement fixation (MC'F) which indicated a clear separation of North, Central, and South American lineages of Bufo. The South American lineage likely diverged from the Central and North American lineages in the Eocene; the latter two lineages diverged later, probably in the mid-Oligocene. Some species groups of South American toads, defined on the basis of traditional morphological studies, are genetically quite similar within groups, whereas others are genetically divergent. The amount of albumin evolution does not appear to parallel the amount of karyotypic, morphological, ecological, or behavioral evolution documented. Comparisons suggest that the African lineages separated from the American and Asian lineages in the late Cretaceous, corresponding to the time of the final separation of Gondwanaland, the southern supercontinent including the modern continents of South America, Africa, Australia, Antarctica, and India. The Asian lineages diverged from the lineage giving rise to all of the American species in the early Paleocene.

Animals↗
PubMed2006

Phylogenomics of the genus Mus (Rodentia; Muridae): extensive genome repatterning is not restricted to the house mouse.

The house mouse (Mus musculus) is universally adopted as the mammalian laboratory model, and it is involved in most studies of large-scale comparative genomics. Paradoxically, this taxon is rarely the index species for evolutionary analyses of genome architecture owing to its highly rearranged karyotype. To unravel the origin and nature of this extensive repatterning genome, we performed a multidirectional chromosome painting study of representative species within the genus Mus. However, the latter includes four extant subgenera (Mus, Coelomys, Nannomys and Pyromys) between which the phylogenetic relationships remain elusive despite the numerous molecular studies. Comparative genomic maps were established using chromosome-specific painting probes of the laboratory mouse and Nannomys minutoides. Hence, by integrating closely related species within Mus, this study allowed us to: (i) unambiguously resolve for the first time the long-standing controversial phylogeny, (ii) trace the evolution of genome organization in the house mouse, (iii) track rearrangements that necessitated new centromere locations, i.e. formation of neocentromere or reactivation of latent centromeres, (iv) reveal an extremely high rate of karyotypic evolution, with a 10- to 30-fold acceleration which was coincidental with subgeneric cladogenesis and (v) highlight genomic areas of interest for high-resolution studies on neocentromere formation and synteny breakpoints.

Animals↗
PubMed1987

Chromosomal evolution of the Canidae. II. Divergence from the primitive carnivore karyotype.

The Giemsa-banding patterns of chromosomes from the arctic fox (Alopex lagopus), the red fox (Vulpes vulpes), the kit fox (Vulpes macrotis), and the raccoon dog (Nyctereutes procyonoides) are compared. Despite their traditional placement in different genera, the arctic fox and the kit fox have an identical chromosome morphology and G-banding pattern. The red fox has extensive chromosome arm homoeology with these two species, but has only two entire chromosomes in common. All three species share some chromosomes with the raccoon dog, as does the high diploid-numbered grey wolf (Canis lupus, 2n = 78). Moreover, some chromosomes of the raccoon dog show partial or complete homoeology with metacentric feline chromosomes which suggests that these are primitive canid chromosomes. We present the history of chromosomal rearrangements within the Canidae family based on the assumption that a metacentric-dominated karyotype is primitive for the group.

Animals↗
PubMed1992

DNA ploidy and karyotype in recurrent and metastatic soft tissue sarcomas.

To study mechanisms involved in evolution of soft tissue sarcomas, we compared DNA ploidy and karyotypes at different stages of their disease in two patients with myxoid liposarcomas (MLS), one with a fibrosarcoma (FS), and two with rhabdomyosarcomas (RMS). None of the MLS samples revealed clearcut histologic changes in later samples as compared to their primaries, and the DNA ploidy in all samples was diploid. In one patient karyotypes at four different times during the 19 yr of his disease all revealed a t(11;12) (p15;q13), but additional clonal chromosomal abnormalities occurred only in later recurrences. In another patient the karyotypes obtained in the 26th and 28th yr of his disease were similar and included the t(12;16) (q13;p11), characteristic of MLS. A comparison with karyotypes of six other MLS patients at different disease stages suggests that the presence of a t(12;16) may correlate with less aggressive clinical behavior. The histology of the FS remained low-grade and the DNA ploidy diploid. The karyotype, however, showed evolution. In both MLS and FS, chromosomal changes thus seem to be a more sensitive marker for tumor progression than histologic changes or DNA ploidy. In one embryonal RMS, karyotypes obtained 7 and 11 yr after the primary diagnosis were different but clearly had a common "progenitor." In one alveolar RMS, the primary and the synchronous lung and lymph node metastases all revealed a t(2;13). The findings in RMS suggest that polyploidization is an early event in tumor evolution, especially in the alveolar subtype, which may be followed by additional chromosomal changes. In addition, DNA ploidy was measured in eight other RMSs. Among the RMSs the embryonal subtype was characterized by DNA aneuploidy, whereas three of the alveolar cases were in the tetraploid range and one was peridiploid. In local recurrences and in metastases changes in DNA index were observed in half the cases.

Adolescent↗
PubMed2026

Molecular divergence and genomic composition of B chromosomes in the fish Cyphocharax modestus (Characiformes, Curimatidae).

B chromosomes are supernumerary elements that evolve from standard A chromosomes and are primarily composed of repetitive DNAs, yet their origin, diversification, and molecular composition remain poorly understood in most vertebrates. We investigated two allopatric populations of Cyphocharax modestus (Curimatidae) combining classical cytogenetics, comparative genomic hybridization (CGH), and comparative satellitomics to characterize the repetitive DNA landscape of its B chromosomes. While both populations exhibited a conserved karyotype of 2n=54 biarmed chromosomes, five individuals from the Batalha River (BR) carried supernumerary chromosomes, comprising two distinct variants: a C-positive B1 and an C-negative B2. Comparative satellitome analysis between 3B-carrying and B-lacking individuals identified 116 satellite DNAs (CmoSatDNAs), with the 3B library showing higher abundances of specific sequences. Fluorescence in situ hybridization (FISH) revealed that both B variants share two centromeric satellites (CmoSat01-192 and CmoSat02-108) with the A complement, while CmoSat58-47 was exclusively to B2. Minimum spanning tree analysis of CmoSat58-47 revealed B-exclusive haplotypes alongside haplotypes shared with B-lacking individuals, suggesting a recent origin for these chromosomes. CGH experiments further confirm the sequence sharing between the A and B chromosomes, supporting an intraspecific origin, and revealing substantial genomic differentiation among B variants.

Animals↗
PubMed1961

Chromosomes of lemurine lemurs.

A wide variation in chromosome number and morphology was observed among different species and subspecies of lemurine lemurs. Comparative karyotype analysis indicates close phylogenic relationships and strongly suggests that chromosome structural rearrangements may have played an important role in the evolution of this group of primates.

Animals↗
PubMed1983

Extensive chromosomal repatterning in two congeneric species: Pytilia melba, L. and Pytilia phoenicoptera Swainson (Estrildidae; Aves).

Chromosomal analysis of two species of African finches of the genus Pytilia has been carried out using both G- and C-banding. The karyotypes of these two species were found to differ radically, not only from each other, but also from those of other species in the family Estrildidae. The differences are due to paracentric and pericentric inversions and to tandem fusions. However, not all of the karyotypic differences can be explained by conventional mechanisms. These results are discussed in relation to the role of karyotypic rearrangement in avian evolution and the conversion of microchromosomes to macrochromosomes.

Animals↗
PubMed2003

Chromosomal phylogeny and evolution of gibbons (Hylobatidae).

Although human and gibbons are classified in the same primate superfamily (Hominoidae), their karyotypes differ by extensive chromosome reshuffling. To date, there is still limited understanding of the events that shaped extant gibbon karyotypes. Further, the phylogeny and evolution of the twelve or more extant gibbon species (lesser apes, Hylobatidae) is poorly understood, and conflicting phylogenies have been published. We present a comprehensive analysis of gibbon chromosome rearrangements and a phylogenetic reconstruction of the four recognized subgenera based on molecular cytogenetics data. We have used two different approaches to interpret our data: (1) a cladistic reconstruction based on the identification of ancestral versus derived chromosome forms observed in extant gibbon species; (2) an approach in which adjacent homologous segments that have been changed by translocations and intra-chromosomal rearrangements are treated as discrete characters in a parsimony analysis (PAUP). The orangutan serves as an "outgroup", since it has a karyotype that is supposed to be most similar to the ancestral form of all humans and apes. Both approaches place the subgenus Bunopithecus as the most basal group of the Hylobatidae, followed by Hylobates, with Symphalangus and Nomascus as the last to diverge. Since most chromosome rearrangements observed in gibbons are either ancestral to all four subgenera or specific for individual species and only a few common derived rearrangements at subsequent branching points have been recorded, all extant gibbons may have diverged within relatively short evolutionary time. In general, chromosomal rearrangements produce changes that should be considered as unique landmarks at the divergence nodes. Thus, molecular cytogenetics could be an important tool to elucidate phylogenies in other species in which speciation may have occurred over very short evolutionary time with not enough genetic (DNA sequence) and other biological divergence to be picked up.

Animals↗
PubMed1996

Diagnostic and prognostic significance of cytogenetics in adult primary myelodysplastic syndromes.

Cytogenetic analysis has proven to be a mandatory part of the diagnosis of myelodysplastic syndromes (MDS) as well as a major indicator for predicting clinical course and outcome. This review concentrates on the cytogenetic classifications, the incidence and types of chromosome defects and the prognostic significance of the karyotype in adult primary MDS. Two cytogenetic classifications are currently used: one is based on the karyotype complexity (normal, single, double or complex defects), the other on clonal status (all metaphases normal, abnormal or admixture of normal and abnormal clones). Chromosome abnormalities are of both numerical and structural types. Aside from the 5q-syndrome, no specific clinico-cytogenetic entity has been reported. However, several distinct clinical and cellular features have been identified that correlate with the presence of specific chromosome defects such as inv(3)/t(3;3), +6, t(5;12), del(17p) and del(20q). The presence of complex defects is associated with reduced survival and a high risk of leukemic transformation. Among single defects, specific abnormalities may define distinct prognostic groups. Patients with del(5q) as a sole chromosome defect and a refractory anemia without excess of blasts have a favourable prognosis. For patients with trisomy 8 or monosomy 7 there may be distinct types of clinical evolution. Most patients with the 3q21q26 syndrome have a short survival. The presence of two chromosome defects may constitute an independent cytogenetic entity probably associated with relative poor prognosis. Karyotypic evolution generally represents a poor risk factor. The combination of cytogenetics with clinical and hematological features has proven to provide for a better prediction of patients' survival, leukemic transformation and response to treatment. Several scoring systems have been developed. They have to be improved by the study of new patients according to strict clinical and cytogenetic criteria and by the addition of newly recognized prognostic indicators such as histopathological features and molecular genetic mutations.

Adult↗
PubMed2025

Cytotype classification and genetic diversity of Platostoma palustre revealed by rDNA localization and chloroplast genome.

BACKGROUND: Platostoma palustre A. J. Paton is an edible medicinal plant that plays a significant role in traditional food production and medicinal applications. However, the genetic basis of P. palustre remains unclear, thereby hampering research on its genome and polyploid evolution. RESULTS: To characterize the karyotype and ploidy of P. palustre, we performed fluorescence in situ hybridization (FISH) by using 35 S and 5 S rDNA probes in P. palustre. FISH results indicated that 35 S rDNA mapped to the end of the chromosome (chromosome satellite, heterochromatic region) and that 5 S rDNA was located close to the centromere of the chromosomes. Based on the rDNA sites, we identified three distinct cytotypes of P. palustre: diploid (2n = 2x = 30, x = 15), triploid (2n = 3x = 45, x = 15), and tetraploid (2n = 4x = 60, x = 15). To further explore the genetic evolutionary relationship among these P. palustre cytotypes, we conducted Illumina sequencing and assembled the chloroplast (CP) genome. The CP genomes of P. palustre accessions maintained a conserved single circular molecule with a length of 152,534 - 152,788 bp, comprising a large single-copy region (LSC) and small single-copy region (SSC) separated by two inverted repeat regions (IRs). Phylogenetic trees were also created based on CP and nuclear molecular markers, showing that most P. palustre accessions clustered together corresponding to their collection regions. Of these, GDZC2 (2n = 2x = 30) clustered with several triploid accessions, suggesting that it may share a common ancestor with these triploid accessions. CONCLUSIONS: This is the first study to characterize the karyotype, identify three cytotypes of P. palustre using FISH, and provide molecular evidence for an evolutionary relationship among different P. palustre accessions. These findings will be useful for further genomic studies and polyploid evolution of P. palustre.

Genome, Chloroplast↗
PubMed1996

Recent fusion events during evolution of pig chromosomes 3 and 6 identified by comparison with the babirusa karyotype.

The chromosomes of the babirusa, a species considered to have diverged from an ancestor of the pig during the Miocene epoch, about 12-26 million years ago, were studied to determine the sites of recent rearrangements during evolution of the domestic pig. It is shown that there is a pericentric inversion of the entire short arm on pig chromosome 1, compared to its counterpart in the babirusa (chromosome 15). We also present evidence suggesting that pig chromosome 3 was derived by a telomere-centromere fusion of two ancestral chromosomes homoelogous to babirusa chromosomes 12 and 17. Likewise, we conclude that pig chromosome 6 was most likely derived by a telomere-telomere fusion of ancestral chromosomes homoelogous to babirusa chromosomes 6 and 14. The detection of interstitial hybridization signals from presumptive subteloemeric repeats in the same chromosome region as the evolutionary fusion points on pig chromosomes 3 and 6 indicates that the fusion sites may still contain elements that are otherwise restricted to the telomere regions of pig chromosomes.

Animals↗
PubMed1976

[A cytotaxonomic study of Rumex. IV. The Acetosa Mill. species].

1. Karyotypes of 18 species of the sections Scutati (2), Vesicarii (2), Hastati (4), Afroacetosae (2) and Acetosa (8) of the genus Acetosa have been investigated in detail. 2. Four evolutive tendancies were distinguished i.e.: decrease of chromosome number and arm ratio, increase of chromosome length and differentiation of sex crhomosomes. These tendancies are fully expressed in the section Acetosa as compared with the others. 3. In this section, relationships between the subsections Acetosa, Insectivalves and Americanae were established especially dealing with the change of sex determination from the type XX/XY to the type XX/XY1Y2. 4. Evolutive pathways within the genus Acetosa as well as in the whole group of Rumex sensu lato are described.

Biological Evolution↗
PubMed1991

The karyotypes of Triaenophorus nodulosus and T. crassus (Cestoda: Pseudophyllidea).

Two species of the genus Triaenophorus were found to have widely different chromosome sets. The karyotype of T. nodulosus consists of 26 biarmed chromosomes ranging from 1.45 to 6.75 microns long. The diploid set of T. crassus contains 18 chromosomes with a well-distinguished first pair of large metacentric homologues. All the chromosomes with the exception of the last pair of acrocentric elements are biarmed. Their absolute length ranges from 1.50 to 8.50 microns. The possible pathways of karyotype differentiation and the evolution of these species are discussed.

Animals↗