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PubMed2004

Comparative chromosome painting between the domestic pig (Sus scrofa) and two species of peccary, the collared peccary (Tayassu tajacu) and the white-lipped peccary (T. pecari): a phylogenetic perspective.

The Suidae and the Dicotylidae (or Tayassuidae) are related mammalian families, both belonging to the artiodactyl suborder Suiformes, which diverged more than 37 million years ago. Cross-species chromosome painting was performed between the domestic pig (Sus scrofa; 2n = 38), a representative of the Suidae, and two species of the Dicotylidae: the collared peccary (Tayassu tajacu; 2n = 30) and the white-lipped peccary (T. pecari; 2n = 26). G-banded metaphase chromosomes of the two peccaries were hybridized with whole chromosome painting probes derived from domestic pig chromosomes 1-18 and X. For both peccary species, a total of 31 autosomal segments that are conserved between pig and peccary could be identified. The painting results confirm conclusions inferred from G-band analyses that the karyotypes of the collared peccary and the white-lipped peccary are largely different. The karyotypic heterogeneity of the Dicotylidae contrasts with the relative homogeneity among the karyotypes of the Suidae. For this difference between the Dicotylidae and the Suidae, a number of explanations are being postulated: 1) the extant peccaries are phylogenetically less closely related than is usually assumed; 2) the peccary genome is less stable than the genome of the pigs; and 3) special (e.g. biogeographical or biosocial) circumstances have facilitated the fixation of chromosome rearrangements in ancestral dicotylid populations.

Animals↗

PubMed1995

Chromosome analysis of 97 primary breast carcinomas: identification of eight karyotypic subgroups.

Chromosome banding analysis of 97 short-term cultured primary breast carcinomas revealed clonal aberrations in 79 tumors, whereas 18 were karyotypically normal. In 34 of the 79 tumors with abnormalities, two to eight clones per case were detected; unrelated clones were present in 27 (34%) cases, whereas only related clones were found in seven. These findings indicate that a substantial proportion of breast carcinomas are of polyclonal origin. Altogether eight abnormalities were repeatedly identified both as sole chromosomal anomalies and as part of more complex karyotypes: the structural rearrangements i(1)(q10), der(1:16)(q10;p10), del(1)(q11-12), del(3)(p12-13p14-21), and del(6)(q21-22) and the numerical aberrations +7, +18, and +20. At least one of these changes was found in 41 (52%) of the karyotypically abnormal tumors. They identify a minimum number of cytogenetic subgroups in breast cancer and are likely to represent primary chromosome anomalies in this type of neoplasia. Other candidates for such a role are translocations of 3p12-13 and 4q21 with various partner chromosomes and inversions of chromosome 7, which also were seen repeatedly. Additional chromosomal aberrations that give the impression of occurring nonrandomly in breast carcinomas include structural rearrangements leading to partial monosomies for 1p, 8p, 11p, 11q, 15p, 17p, 19p, and 19q and losses of one copy of chromosomes X, 8, 9, 13, 14, 17, and 22. The latter changes were seen consistently only in complex karyotypes, however, and we therefore interpret them as being secondary anomalies acquired during clonal evolution.

Breast Neoplasms↗

PubMedDate not supplied

Growth and progression of head and neck cancer: a report of the Upper Aerodigestive Cancer Task Force Workshop.

Factors governing the initiation, growth, and progression of squamous cell carcinoma were the focus of a recent Upper Aerodigestive Cancer Task Force workshop sponsored by the National Cancer Institute. The goal of the daylong workshop was to identify critical research concepts in head and neck cancer biology. Discussed were the multistep processes potentially involved in tumor evolution, including the role of carcinogens, viral promotors, host and tumor karyotypes, microenvironment growth factors and growth factor receptors, as well as host/tumor components inherent to the metastatic process. Concepts developed from research in other neoplastic processes but potentially relevant to head and neck cancer were emphasized. The process of identifying critical research directions is the first step by the National Cancer Institute in program development designed to advance the treatment of head and neck cancer.

Carcinogens↗

PubMed1993

Cytogenetic survey of 32 cancers of the prostate.

Cytogenetic studies after short-term culture were performed on 32 adenocarcinomas of the prostate from patients without prior treatment. The tumor specimens, ranging from stage B1 to D1, were obtained by radical prostatectomy or diagnostic biopsies. Fourteen tumors showed a normal diploid chromosome complement in all metaphases examined. Clonal chromosomal alterations were detected in 16 tumor samples and the remaining two cases contained double minute (dmin) chromosomes in some cells. The most frequent numerical changes included loss the Y chromosome and trisomy 7, both found in four cases. The only recurrent structural aberration was del(10)(q24), seen in three cases both as a sole anomaly and within multiple rearrangements. Six patients showed cytogenetically unrelated clones. The occurrence of the chromosomal changes found in this study shows no relationship to certain histopathologic characteristics of the tumors. The recurrent finding of del(10)(q24) as sole anomaly and the evidence for clonal evolution in one patient demonstrates that this change is an early karyotypic event which may be important for the pathogenesis in at least a subset of prostatic cancers.

Chromosome Aberrations↗

PubMed1998

Evolutionary conservation of whole homeologous chromosome arms in the Akodont rodents Bolomys and Akodon (Muridae, Sigmodontinae): maintenance of interstitial telomeric segments (ITBs) in recent event of centric fusion.

We have identified the almost complete correspondence of whole chromosome arms between the karyotypes of Bolomys lasiurus (2n = 33, 34) and Akodon montensis (2n = 24, 25) using comparative analysis of the GTG-banding patterns. To explain the karyotypic differentiation of the species, tandem and centric fusions, pericentric inversions, loss of telomeres and centromeres are required. Localization of telomere sequences using an (TTAGGG)n oligomere as a fluorescence in situ hybridization probe provided evidence of the maintenance of interstitial telomere sequences in a polymorphic centric fusion of recent origin in Bolomys lasiurus. The homeologies shared between the chromosomes of these two species and those of A. cursor (2n = 16), from previous work, are discussed.

Animals↗

PubMed2005

Ploidy, as detected by fluorescence in situ hybridization, defines different subgroups in multiple myeloma.

Ploidy appears as an important parameter in both the biology and the clinical evolution of multiple myeloma. However, its evaluation requires either a successful karyotyping (obtained in 30% of the patients) or a DNA index calculation by flow cytometry (not routinely performed in myeloma). We validated a novel method based on interphase fluorescence in situ hybridization that can be utilitized to analyze almost all the patients. The method was very specific and sensitive for the detection of hyperdiploidy. Extended studies showed that most recurrent 14q32 translocations occur in nonhyperdiploid clones, and that deletions of chromosome 13 were less frequently observed in hyperdiploid clones (48 vs 66%). Further large studies are ongoing to evaluate the prognostic value of ploidy in myeloma.

Disease Progression↗

PubMed1988

Initial clonal acute lymphoblastic transformation of chronic lymphocytic leukemia with (11;14) and (8;12) chromosome translocations and acquired homozygosity.

A 69-year-old woman presented with chronic lymphocytic leukemia (CLL) diagnosed after bone marrow recovery following intensive chemotherapy for acute lymphoblastic leukemia. The retrospective diagnosis of initial blastic transformation of CLL was made. The patient eventually died, 5 months after initial blastic phase, from a blastic relapse of her CLL. Immunologic and karyotypic studies of the lymphoid cells at different times during the evolution of the disease provided evidence that both the small lymphocytes and the large blastic cells originated from the same clone since they carried the same surface markers and the same (11;14) (q13;q32) translocation. A subpopulation of cells carried in addition a t(8;12) (q24;q22) together with the loss of the normal chromosome 8 and homozygosity for the abnormal der(8). The possibility that this second population might correspond to the blast cells and that the occurrence of the t(8;12) with homozygosity might be linked to blastic transformation of the CLL is discussed.

Aged↗

PubMed1992

[Masked Philadelphia chromosome: diagnostic implications in a case of chronic myeloid leukemia presenting in blast crisis].

We present a female patient with acute non-lymphoblastic leukemia (ANLL) and with haematologic features suggestive of its evolution from chronic myeloid leukaemia (CML), in which a bone marrow karyotype showing a "masked" Philadelphia (Ph) chromosome due to a variant translocation of complex type t(9;9;22)(q32;q34;q11) was found. We comment the peculiarities of this special Ph chromosome as well as the differential diagnostic problems between ANLL Ph(+) and CML with onset in blastic crisis.

Aged↗

PubMed2002

Origin and evolution of avian microchromosomes.

The origin of avian microchromosomes has long been the subject of much speculation and debate. Microchromosomes are a universal characteristic of all avian species and many reptilian karyotypes. The typical avian karyotype contains about 40 pairs of chromosomes and usually 30 pairs of small to tiny microchromosomes. This characteristic karyotype probably evolved 100-250 million years ago. Once the microchromosomes were thought to be a non-essential component of the avian genome. Recent work has shown that even though these chromosomes represent only 25% of the genome; they encode 50% of the genes. Contrary to popular belief, microchromosomes are present in a wide range of vertebrate classes, spanning 400-450 million years of evolutionary history. In this paper, comparative gene mapping between the genomes of chicken, human, mouse and zebrafish, has been used to investigate the origin and evolution of avian microchromosomes during this period. This analysis reveals evidence for four ancient syntenies conserved in fish, birds and mammals for over 400 million years. More than half, if not all, microchromosomes may represent ancestral syntenies and at least ten avian microchromosomes are the product of chromosome fission. Birds have one of the smallest genomes of any terrestrial vertebrate. This is likely to be the product of an evolutionary process that minimizes the DNA content (mostly through the number of repeats) and maximizes the recombination rate of microchromosomes. Through this process the properties (GC content, DNA and repeat content, gene density and recombination rate) of microchromosomes and macrochromosomes have diverged to create distinct chromosome types. An ancestral genome for birds likely had a small genome, low in repeats and a karyotype with microchromosomes. A "Fission-Fusion Model" of microchromosome evolution based on chromosome rearrangement and minimization of repeat content is discussed.

Animals↗

PubMed2003

Reciprocal chromosome painting among human, aardvark, and elephant (superorder Afrotheria) reveals the likely eutherian ancestral karyotype.

The Afrotheria, a supraordinal grouping of mammals whose radiation is rooted in Africa, is strongly supported by DNA sequence data but not by their disparate anatomical features. We have used flow-sorted human, aardvark, and African elephant chromosome painting probes and applied reciprocal painting schemes to representatives of two of the Afrotherian orders, the Tubulidentata (aardvark) and Proboscidea (elephants), in an attempt to shed additional light on the evolutionary affinities of this enigmatic group of mammals. Although we have not yet found any unique cytogenetic signatures that support the monophyly of the Afrotheria, embedded within the aardvark genome we find the strongest evidence yet of a mammalian ancestral karyotype comprising 2n = 44. This karyotype includes nine chromosomes that show complete conserved synteny to those of man, six that show conservation as single chromosome arms or blocks in the human karyotype but that occur on two different chromosomes in the ancestor, and seven neighbor-joining combinations (i.e., the synteny is maintained in the majority of species of the orders studied so far, but which corresponds to two chromosomes in humans). The comparative chromosome maps presented between human and these Afrotherian species provide further insight into mammalian genome organization and comparative genomic data for the Afrotheria, one of the four major evolutionary clades postulated for the Eutheria.

Animals↗

PubMed2003

Evolutionary experimentation through hybridization under laboratory condition in Drosophila: evidence for recombinational speciation.

BACKGROUND: Drosophila nasuta nasuta (2n = 8) and Drosophila nasuta albomicans (2n = 6) are a pair of sibling allopatric chromosomal cross-fertile races of the nasuta subgroup of immigrans species group of Drosophila. Interracial hybridization between these two races has given rise to new karyotypic strains called Cytorace 1 and Cytorace 2 (first phase). Further hybridization between Thailand strain of D. n. albomicans and D. n. nasuta of Coorg strain has resulted in the evolution of two more Cytoraces, namely Cytorace 3 and Cytorace 4 (second phase). The third phase Cytoraces (Cytorace 5 to Cytorace 16) have evolved through interracial hybridization among first, second phase Cytoraces along with parental races. Each of these Cytoraces is composed of recombined genomes of the parental races. Here, we have made an attempt to systematically assess the impact of hybridization on karyotypes, morphometric and life history traits in all 16 Cytoraces. RESULTS: The results reveal that in most cases, the newly evolved Cytoraces, with different chromosome constitutions, exhibit decreased body size, better fitness and live longer than their parents. Particularly, Cytorace 5, 6 and 8 have evolved with very much higher range values of quantitative traits than the parents and other Cytoraces, which suggests the role of transgressive segregation in the evolution of these Cytoraces. CONCLUSION: Thus, the rapid divergence recorded in the chromosomes, karyotypes, body size and fitness traits of Cytoraces exhibit the early event of recombinational raciation / speciation in the evolution of the Cytoraces under laboratory conditions.

Animals↗

PubMed1991

Karyotypic variability and evolutionary characteristics of a polymorphous low grade adenocarcinoma in the parotid gland.

The chromosomes of a polymorphous low-grade adenocarcinoma originating from a pleomorphic adenoma of the parotid gland were studied. Three successful preparations were performed. A minor fraction of cells showed normal karyotypes and some cells only inconsistent, usually numerical, deviations. The remaining cells constituted an abnormal monoclonal population with an unusual and very extensive karyotypic variability. The origin of most marker chromosomes could be wholly or partly clarified. Five different subclones could be distinguished on basis of different specific marker chromosomes. The characteristics of the marker sets suggested a closely interrelated derivation of the subclones. The results also provide insight as to the influence of random factors and/or differential growth rate on the chromosomal picture observed in in vitro systems. The present chromosomal observations showed no similarities either to the cytogenetical findings in the five previously reported salivary gland adenocarcinomas or to the deviations seen in the single studied case of carcinoma ex-pleomorphic adenoma.

Adenocarcinoma↗

PubMed1986

Acute promyelocytic leukemia. M.D. Anderson Hospital experience.

Sixty patients with acute promyelocytic leukemia were treated between 1973 and 1984. The overall median survival was 16 months with a five-year survival rate of 31 percent. The complete remission rate was 53 percent and was similar whether they received amsacrine- or anthracycline-based regimens (60 percent versus 51 percent). The median remission duration was 29 months. At five years, 43 percent of patients with responses to treatment had continuous remission and 57 percent were alive. Salvage therapy produced remissions in 53 percent of patients during first relapse, with two long-term survivors after further consolidation with bone marrow transplantation. Early fatal hemorrhage associated with disseminated intravascular coagulopathy during induction therapy occurred in 16 patients (26 percent). Multivariate analysis of the pretreatment patient characteristics significantly associated with an increased risk of fatal hemorrhage identified four that have primary prognostic importance: thrombocytopenia, elevated absolute blast and promyelocyte counts, old age, and anemia. Patients having up to two unfavorable features had a low risk of fatal hemorrhage compared with those who had more than two (5 percent versus 58 percent; p less than 0.0001). Overall, patients who received heparin had a lower incidence of fatal hemorrhage than those who did not (19 percent versus 32 percent). Heparin therapy was not beneficial to those at low risk but was associated with a trend towards decreased hemorrhagic deaths among high-risk patients (45 percent versus 67 percent). Cytogenetic studies demonstrated the characteristic 15;17 translocation in 73 percent of patients with analyzable metaphases, whereas 12 percent had other karyotypic abnormalities. Remission induction was often associated with a gradual atypical morphologic evolution into remission without intermediate hypoplasia with the interim marrows showing a high proportion of blasts. It is concluded that acute promyelocytic leukemia is a unique disease with a high potential for cure. Knowledge of its prognosis using present frontline and salvage therapy, of the factors related to fatal hemorrhage, and of the unusual patient marrow profiles during remission induction may improve the therapeutic approach.

Aminoacridines↗

PubMed2003

Cross-species chromosome painting in the Perissodactyla: delimitation of homologous regions in Burchell's zebra (Equus Burchellii) and the white (Ceratotherium Simum) and black rhinoceros (Diceros Bicornis).

Conserved chromosomal segments in the black rhinoceros, Diceros Bicornis (DBI, 2n = 84), and its African sister-species the white rhinoceros, Ceratotherium Simum (CSI, 2n = 82), were detected using Burchell's zebra (Equus Burchellii, EBU, 2n = 44) chromosome-specific painting probes supplemented by a subset of those developed for the horse (Equus Caballus, ECA, 2n = 64). In total 41 and 42 conserved autosomal segments were identified in C. Simum and D. Bicornis respectively. Only 21 rearrangements (20 fissions and 1 fusion) are necessary to convert the Burchell's zebra karyotype into that of the white rhinoceros. One fission distinguishes the D. Bicornis and C. Simum karyotypes which, excluding heterochromatic differences, are identical in all respects at this level of resolution. Most Burchell's zebra chromosomes correspond to two rhinoceros chromosomes although in four instances (EBU18, 19, 20 and 21) whole chromosome synteny has been retained among these species. In contrast, one rhinoceros chromosome (DBI1, CSI1) comprises two separate Burchell's zebra chromosomes (EBU11 and EBU17). In spite of the high diploid numbers of the two rhinoceros species their karyotypes are surprisingly conserved offering a glimpse of the putative ancestral perissodactyl condition and a broader understanding of genome organization in mammals.

Animals↗

PubMed2005

Recent radiation in West African Taterillus (Rodentia, Gerbillinae): the concerted role of chromosome and climatic changes.

West African gerbils of the genus Taterillus constitute a complex of seven sibling species distributed from sudano-guinean to saharo-sahelian regions. They display radically rearranged karyotypes despite low genic divergence and a very recent differentiation, that is, within the last 0.4 Myr for the six most derived species. We here provide a comparison of the seven specific karyotypes and perform a cladistic analysis using chromosomal rearrangements character states. When a posteriori polarized mutations were mapped onto the phylogenetic tree, 38 rearrangements were identified as fixed during the evolution of these rodents. This makes Taterillus one of the most striking examples of accelerated chromosomal evolution within placental mammals. Taking into account the types of chromosomal changes involved, divergence times between lineages, genetic distances, as well as reassessed geographic distributions, we suggest that (1) speciation in West African Taterillus was driven by chromosomal changes, and (2) the paleoclimatic oscillations of the Sahara desert have played a major role in their evolution. In particular, elevated plasticity of the Taterillus genome, as suggested by the patterns observed for some repetitive elements, would have led to a higher probability of mutation. We hypothesize that the process underpinning cladogenesis most probably involved highly underdominant genomic rearrangements that were fixed following pronounced populational bottlenecks resulting from drastic climatic and subsequent environmental changes. Major African rivers formed significant barriers to dispersal, limiting expansion during the more moist and so favorable periods. This scenario would explain the current parapatric species distributions and their relationship to the West African hydrographic features.

Animals↗

PubMed2001

Reconstruction of the female Gorilla gorilla karyotype using 25-color FISH and multicolor banding (MCB).

The origin of the human and great ape chromosomes has been studied by comparative chromosome banding analysis and, more recently, by fluorescence in situ hybridization (FISH), using human whole-chromosome painting probes. It is not always possible, however, to determine the exact breakpoints and distribution or orientation of specific DNA regions using these techniques. To overcome this problem, the recently developed multicolor banding (MCB) probe set for all human chromosomes was applied in the present study to reanalyze the chromosomes of Gorilla gorilla (GGO). While the results agree with those of most previous banding and FISH studies, the breakpoints for the pericentric inversion on GGO 3 were defined more precisely. Moreover, no paracentric inversion was found on GGO 14, and no pericentric inversions could be demonstrated on GGO 16 or 17.

Animals↗

PubMed1990

Meiotic chromosome behaviour reflects levels of sequence divergence in Sus scrofa domestica satellite DNA.

We present a general model for the evolution of chromosome-specific satellite DNA subfamilies. Sus scrofa domestica has a bimodal karyotype with two autosomal subsets of 12 meta-/submetacentric (Mc) and 6 acrocentric (Ac) chromosome types (Mc and Ac "subgenomes"). We show that the centromeric heterochromatin is characterised by two distinct satellite DNA families designed Mc1 and Ac2. Mc1 is a diverse satellite family of the Mc subgenome of which certain members with a 100 bp repeat unit are found to occur at the pericentromeric regions of each Mc autosome, while others are chromosome-specific, e.g. clone Mc pAv1.5, a higher order repeat variant, which hybridises specifically to chromosome 1. Ac2 is a homogeneous satellite occurring at the subterminal pericentromeric regions of all Ac autosomes. DNA sequence analyses showed that all clones investigated are built up from a 14 bp repeat unit which is highly conserved. In situ hybridisation to meiotic pachytene nuclei revealed a distinct spatial arrangement of the Ac2 centromeric satellite.

Animals↗

PubMed2006

Mechanisms of chromosome number reduction in Arabidopsis thaliana and related Brassicaceae species.

Evolution of chromosome complements can be resolved by genome sequencing, comparative genetic mapping, and comparative chromosome painting. Previously, comparison of genetic maps and gene-based phylogenies suggested that the karyotypes of Arabidopsis thaliana (n = 5) and of related species with six or seven chromosome pairs were derived from an ancestral karyotype with eight chromosome pairs. To test this hypothesis, we applied multicolor chromosome painting using contiguous bacterial artificial chromosome pools of A. thaliana arranged according to the genetic maps of Arabidopsis lyrata and Capsella rubella (both n = 8) to A. thaliana, A. lyrata, Neslia paniculata, Turritis glabra, and Hornungia alpina. This approach allowed us to map the A. lyrata centromeres as a prerequisite to defining a putative ancestral karyotype (n = 8) and to elucidate the evolutionary mechanisms that shaped the karyotype of A. thaliana and its relatives. We conclude that chromosome "fusions" in A. thaliana resulted from (i) generation of acrocentric chromosomes by pericentric inversions, (ii) reciprocal translocation between two chromosomes (one or both acrocentric), and (iii) elimination of a minichromosome that arose in addition to the "fusion chromosome." Comparative chromosome painting applied to N. paniculata (n = 7), T. glabra (n = 6), and H. alpina (n = 6), for which genetic maps are not available, revealed chromosomal colinearity between all species tested and allowed us to reconstruct the evolution of their chromosomes from a putative ancestral karyotype (n = 8). Although involving different ancestral chromosomes, chromosome number reduction followed similar routes as found within the genus Arabidopsis.

Arabidopsis↗