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PubMed1998

Nonrandom numerical chromosome abnormalities in basal cell carcinomas.

Clonal chromosome abnormalities were found in 22 of 23 short-term cultured basal cell carcinomas (BCC) of the skin. The karyotypic abnormalities were nonrandom and in several cases included evidence of clonal evolution. Especially in cultures showing an epithelial growth pattern, simple numerical changes, most commonly +18, +9, +20, +7, and +5, predominated and presumably constitute pathogenetically important aberrations present in the neoplastic parenchyma. Also, several structural rearrangements of chromosome arm 9q were seen, which may be of particular interest against the background that a gene for familial BCC (Gorlin syndrome), the PTCH gene, maps to this region. Finally, most of the clonal aberrations detected in predominantly fibroblast-like cultures are likely to reflect changes acquired by cells of the tumor stroma, which raises the question whether mutations also of this tumor component may play a pathogenetic role in BCC development.

Adult↗
PubMed2006

Chromosome evolution in the Laurales based on analyses of original and published data.

We present a summary of currently available chromosome information for all seven families in the order Laurales on the basis of original and previously published data and discuss the evolution of chromosomes in this order. Based on a total of 53 genera for which chromosome data were available, basic chromosome numbers appear consistent within families: x = 11 (Calycanthaceae); x = 22 (Atherospermataceae and Siparunaceae); x = 19 (Monimiaceae); and x = 12 and 15 (Lauraceae). The Hernandiaceae have diverse numbers: x = 15 (Gyrocarpoideae) and x = 18 and 20 (Hernandioideae). Karyotype analyses showed that Hennecartia, Kibaropsis, and Matthaea (all Monimiaceae) contained two or three sets of four distinct chromosomes in 38 somatic chromosomes, suggesting that 2n = 38 was derived by aneuploid reduction from 2n = 40, a tetraploid of x = 10. In light of the overall framework of phylogenetic relationships in the Laurales, we show that x = 11 is an archaic base number in the order and is retained in the Calycanthaceae, which are sister to the remainder of the order. Polyploidization appears to have occurred from x = 11 to x = 22 in a common clade of the Siparunaceae, Atherospermataceae, and Gomortegaceae (although 2n = 42 in the Gomortegaceae), and aneuploid reduction from x = 11 to x = 10 occurred in a common clade of the Hernandiaceae, Lauraceae, and Monimiaceae. To understand chromosome evolution in the Lauraceae, however, more studies are needed of genera and species of Cryptocaryeae.

Aneuploidy↗
PubMed1984

Membrane markers, karyotypic abnormalities, ultrastructure and functional properties of lymphocytes in a case of 'D-cell' chronic lymphatic leukemia.

D cells are lymphocytes bearing both receptors for the third complement component and the ability to form spontaneous rosettes with SRBC. We report the case of a patient with a D-cell chronic lymphatic leukemia who presented a long evolution without treatment and whose leukemic cell characteristics have been extensively studied. Cytogenetic analysis showed numerous karyotypic abnormalities among leukemic cells; all metaphases were hypodiploid and arranged in four different clones; seven marker chromosomes were present. The cells were found to bear human T-cell specific antigen, the T helper/inducer phenotype, HLA-A and HLA-B determinants, but no HLA-DR antigens. They displayed a high proliferative response to PHA and Con A, no response to PWM stimulation, and possibly the capacity of allogeneic stimulation in the mixed lymphocyte culture system. Assays for cell-mediated cytotoxicity in the CML system, and for K and NK activities were negative.

Antigens, Surface↗
PubMed2000

Chromosome structure of Triticum timopheevii relative to T. turgidum.

The chromosome structure of four different wild populations and a cultivated line of Triticum timopheevii (2n = 28, AtAtGG) relative to Triticum turgidum (2n = 28, AABB) was studied, using genomic in situ hybridisation (GISH) and C-banding analysis of meiotic configurations in interspecific hybrids. Two wild accessions and the cultivated line showed the standard C-banding karyotype. The other two accessions are homozygous for translocation 5At/3G and translocations 1G/2G and 5G/6G. GISH analysis revealed that all the T. timopheevii accessions carry intergenome translocations 6At/1G and 1G/4G and identified the position of the breakpoint in translocation 5At/3G. C-banding analysis of pairing at metaphase I in the hybrids with T. turgidum provides evidence that four species-specific translocations (6AtS/1GS, 1GS/4GS, 4GS/4AtL, and 4AtL/3AtL) exist in T. timopheevii, and that T. timopheevii and T. turgidum differ in the pericentric inversion of chromosome 4A. Bridge plus acentric fragment configurations involving 4AL and 4AtL were identified in cells at anaphase I. This result suggests that the paracentric inversion of 4AL from T. turgidum does not exist in T. timopheevii. Both tetraploid species have undergone independent and distinct evolutionary chromosomal rearrangements. The position, intercalary or subdistal, of the breakpoints in species-specific translocations and inversions contrasts with the position, at or close to the centromere, of intraspecific translocations. Different mechanisms for intraspecific and species-specific chromosome rearrangements are suggested.

Anaphase↗
PubMed2001

[Probable origin of the Robertsonian phenomena in domestic mice in Tunisia].

The Robertsonian phenomenon in house mice (Mus musculus domesticus) from Tunisia consists in the presence of only one 22-chromosome Robertsonian race (22Rb) carrying the maximum number of fusions observed until now. The 22Rb populations exclusively occupy urban centers in the Eastern-Central region of Tunisia where standard population with 40-all acrocentric chromosomes (40Std) occur in surrounding neighborhoods and rural environments. In addition to the habitat partition, allozyme and mitochondrial DNA analyses showed that the 22Rb populations were genetically differentiated from the 40Std ones. This differentiation mostly stemmed from an important decrease in genetic variability in the 22Rb populations from the Sahel towns. The extent of morphological, ecological and genetical divergence observed between these chromosomal races in Tunisia is in agreement with the predictions of the chromosomal speciation model of White which advocates that karyotypic differentiation between taxa can lead to their reproductive isolation and independent evolution. Such a process is verified if the Rb process in Tunisia results from local differentiation which is supported by both the genetic and morphological data. However, the hypothesis of an origin by introduction of these mice from another region of Tunisia or from another country cannot be totally dismissed. In this study, an allozymic analysis of mice (22Rb and 40Std) from the geographically distant city of Kairouan was performed. Results showed that 22Rb and 40Std mice from Kairouan shared the same high degree of variability, and were not genetically differentiated. This contrasts with the results registered in the two chromosomal races in the Sahel towns. Such data argue in favor of a local differentiation of the Robertsonian process in Tunisia and suggest that the decrease in variability of the structural nuclear genes in the Sahel 22Rb populations can be related to an introduction from Kairouan into a Sahel locality resulting in a founder effect or followed by a severe bottleneck prior to its dispersion throughout the Sahel region.

Animals↗
PubMed1988

Karyotypic conservation in the mammalian order monotremata (subclass Prototheria).

The order Monotremata, comprising the platypus and two species of echidna (Australian and Nuigini) is the only extant representative of the mammalian subclass Prototheria, which diverged from subclass Theria (marsupials and placental mammals) 150-200 million years ago. The 2n = 63 male, 64 female karyotype (newly described here) of the Nuigini echidna is almost identical in morphology and G-band pattern to that of the Australian echidna, from which it diverged about a million years ago. The karyotype of the platypus (2n = 52) has several features in common with those of the echidna species; six pairs of large autosomes, many pairs of small (but not micro-) chromosomes, and a series of small unpaired chromosomes which form a multivalent at meiosis. Comparison of the G-band patterns of platypus and echidna autosomes reveals considerable homology. Chromomycin banding demonstrates GC-rich heterochromatin at the centromeres of many platypus and echidna chromosomes, and at the nucleolar organizing regions; some of this heterochromatin C-bands weakly in platypus (but not echidna) spreads. Late replication banding patterns resemble G-banding patterns and confirm the homologies between the species. Striking heteromorphism between chromosomes of some of the large autosomal pairs can be accounted for in the echidna by differences in amount of chromomycin-bright, late replicating heterochromatin. The sex chromosomes in all three species also bear striking homology, despite the difference in sex determination mechanism between platypus (XX/XY) and the echidna species (X1X1X2X2/X1X2Y). The platypus X and echidna X1 each represent about 5.8% of haploid chromosome length, and are G-band identical. Y chromosomes are similar between species, and are largely homologous to the X (or X1).

Animals↗
PubMed2000

DNA content, rDNA loci, and DAPI bands reflect the phylogenetic distance between Lathyrus species.

The nuclear DNA content, the proportion of A+T base pairs, the chromosomal positions of 5S and 25S rRNA genes, as well as of DAPI (4,6-diamidino-2-phenylindole) bands are described for seven species belonging to three different sections of the genus Lathyrus. These data and chromosome measurements allowed to establish precise idiograms and to discriminate most of the chromosome pairs of the seven species. The karyotypic features correlate well with the phylogenetic distances between these species.

Chromosome Banding↗
PubMed1998

A new derived and highly polymorphic chromosomal race of Liolaemus monticola (Iguanidae) from the 'Norte Chico' of Chile.

A multiple Robertsonian fission chromosomal race of the Liolaemus monticola complex in Chile is described and is shown to be the most derived and the most complex among the Liolaemus examined thus far. The 29 karyotyped lizards analysed from the locality of Mina Hierro Viejo, Petorca, Provincia de Valparaiso, Chile, exhibited a diploid chromosomal number ranging from 42 to 44, and several polymorphisms. The polymorphisms included: a pair 1 fission; a pair 2 fission plus a pericentric inversion in one of the fission products, which moved the NOR and satellite from the tip of the long arm of the metacentric 2 to the short arm of the fission product; a fission in pair 3; a polymorphism for an enlarged chromosome pair 6; and a polymorphism for a pericentric inversion in pair 7. This population is fixed for a fission of chromosome pair 4. A total of 76% of the lizards analysed were polymorphic for one or more pairs of chromosomes. We have compared these data with other Liolaemus monticola chromosomal races and calculated the Hardy-Weinberg ratios for the polymorphic chromosome pairs in this Multiple-Fission race. Karyotypic differences between the Northern (2n = 38-40) and the Multiple-Fission (2n = 42-44) races were attributed mainly to Robertsonian fissions, an enlarged chromosome and pericentric inversions involving the macrochromosomes and one microchromosome pair.

Aneuploidy↗
PubMed1975

Geographical distribution of twelve transferrin alleles in black rats of Asia and Oceania.

About 450 black rats (Rattus rattus) were collected from 25 localities in Asia and Oceania. Their serum transferrins were analyzed by a newly developed thin layer acrylamide gel electrophoresis accompanied with acrinol pretreatment, exhibiting 12 transferrin bands. Generally, Asian type rats (2N=42) had fast-moving transferrins (R-series), Ceylon type (2N=40) moderately moving ones and Oceanian type (2N=38) slowly moving ones (C-series). Exceptionally, in northern India and Pakistan all Asian-type rats had C-series Tf. The possibility that divergence of R-series Tf and C-series Tf had proceeded the karyotypic differentiation from 42 to 38 is proposed. In combination with the previous molecular data, the time of the divergence is roughly estimated between the order of a million years and ten thousand years.

Alleles↗
PubMed1987

t(1;2), inv(1) and trisomy 1q during the blastic phase of Philadelphia chromosome-positive chronic myeloid leukemia.

Several karyotype changes observed during the blastic phase in 2 patients with Philadelphia chromosome (Ph)-positive chronic myeloid leukemia (CML) are reported. Rearrangements involving chromosome 1, i.e., translocations, a pericentric inversion and trisomies of its long arm, are described. In the first patient whose chronic phase was very long (17 years), the uncommon association between i(17q) and Ph duplication has been observed during the blastic phase, beside the involvement of chromosome 1. In the second patient, additional abnormalities involving chromosomes 1, 2, 4, 8, 18 and 21 were present. Of particular interest is the finding of a t(1;2). In this case, the presence of hyperdiploid cells with 49-50 chromosomes, prevailing at the blastic crisis, was due to the evolution of the hypodiploid clone with the 45,XX,t(9;22),-21 karyotype found during the chronic phase. The occurrence of chromosomal changes involving chromosome 1 during the blastic phase of CML is emphasized.

Adult↗
PubMed2000

Evolution of drug resistance in experimental populations of Candida albicans.

Adaptation to inhibitory concentrations of the antifungal agent fluconazole was monitored in replicated experimental populations founded from a single, drug-sensitive cell of the yeast Candida albicans and reared over 330 generations. The concentration of fluconazole was maintained at twice the MIC in six populations; no fluconazole was added to another six populations. All six replicate populations grown with fluconazole adapted to the presence of drug as indicated by an increase in MIC; none of the six populations grown without fluconazole showed any change in MIC. In all populations evolved with drug, increased fluconazole resistance was accompanied by increased resistance to ketoconazole and itraconazole; these populations contained ergosterol in their cell membranes and were amphotericin sensitive. The increase in fluconazole MIC in the six populations evolved with drug followed different trajectories, and these populations achieved different levels of resistance, with distinct overexpression patterns of four genes involved in azole resistance: the ATP-binding cassette transporter genes, CDR1 and CDR2; the gene encoding the target enzyme of the azoles in the ergosterol biosynthetic pathway, ERG11; and the major facilitator gene, MDR1. Selective sweeps in these populations were accompanied by additional genomic changes with no known relationship to drug resistance: loss of heterozygosity in two of the five marker genes assayed and alterations in DNA fingerprints and electrophoretic karyotypes. These results show that chance, in the form of mutations that confer an adaptive advantage, is a determinant in the evolution of azole drug resistance in experimental populations of C. albicans.

AIDS-Related Opportunistic Infections↗
PubMed1997

Cytogenetic abnormalities and clonal evolution in an adult hepatoblastoma.

Hepatoblastomas usually occur in children < 3 years of age, and only occasional adult cases have been described. To date, 20 cytogenetically abnormal childhood hepatoblastomas have been reported. Karyotypic investigations have shown that most hepatoblastomas are diploid or hyperdiploid, often displaying trisomies for chromosomes 2 and 20. We have cytogenetically investigated an adult hepatoblastoma for which no previous karyotypic data exist. A hypertriploid stemline with multiple numerical and structural chromosomal aberrations, including +2 and +20, was found. In addition, the tumor displayed extensive clonal evolution with 11 subclones. Although the tumor thus displayed some chromosomal abnormalities commonly observed in childhood tumors, providing further support for the importance of these abnormalities in the development of hepatoblastoma, the level of genomic complexity seen in the present case has never been described in childhood hepatoblastomas and may suggest a different etiology or pathogenesis.

Aged↗
PubMed2003

Morphologic, karyotypic, and molecular evidence of a new form of Chiropotes (primates, pitheciinae).

Morphologic, karyotypic, and molecular analyses were carried out in 25 specimens of a distinct morph of Chiropotes (henceforth termed Chiropotes sp.) obtained from a number of localities in the Brazilian Amazon. Pelage coloration clearly distinguishes the collected specimens and all other known species of this genus. A distinct karyotype was described for Chiropotes sp. It differs from C. satanas chiropotes by two pericentric inversions, and from C. satanas utahicki by three, which suggests that these taxa are reproductively isolated. Morphometric analyses did not show significant differentiation between these Chiropotes taxa. Molecular analyses confirmed the monophyly of the subfamily Pitheciinae and genera Chiropotes, Cacajao, and Pithecia (the latter appearing as the most basal lineage of the pithecine clade). The genetic distances between C. s. utahicki and Chiropotes sp. from Rio Negro were greater than those between three recognized species of Pithecia, but smaller than those between Cacajao calvus and Cacajao melanocephalus. The most appropriate name for Chiropotes sp. from Rio Negro is C. israelita. This species, C. s. chiropotes, and C. s. utahicki are allopatric. Pelage coloration, karyotype, and molecular analysis strongly indicate that C. chiropotes, C. utahicki, and Chiropotes israelita deserve species status.

Animals↗
PubMed2002

Analysis of chromosome conservation in Lemur catta studied by chromosome paints and BAC/PAC probes.

A panel of human chromosome painting probes and bacterial and P1 artificial chromosome (BAC/PAC) clones were used in fluorescence in situ hybridization (FISH) experiments to investigate the chromosome conservation of the ring-tailed lemur (Lemur catta, LCA) with respect to human. Whole chromosome paints specific for human chromosomes 7, 9, 11, 13, 14, 17, 18, 20, 21, and X were found to identify a single chromosome or an uninterrupted chromosomal region in LCA. A large set of partial chromosome paints and BAC/PAC probes were then used to refine the characterization of the rearrangements differentiating the two karyotypes. The results were also used to reconstruct the ancestral Lemuridae karyotype. Lemur catta, indeed, can be used as an outgroup, allowing symplesiomorphic (ancestral) rearrangements to be distinguished from apomorphic (derived) rearrangements in lemurs. Some LCA chromosomes are difficult to distinguish morphologically. The 'anchorage' of most LCA chromosomes to specific probes will contribute to the standardization of the karyotype of this species.

Animals↗
PubMed1987

A chromosomal profile of polycythemia vera.

One hundred four patients with a diagnosis of polycythemia vera and a variable period of follow-up had one or more cytogenetic investigations. Chromosome abnormalities were found in 13% of untreated patients, in 56% of cases treated with radioactive phosphorus (32P) or cytotoxic drugs, and in 85% of patients in which transformation of the disease had occurred. Nonrandom chromosome abnormalities found before treatment included +8, +9, 13q-, 20q-; their prognostic value is little, as they are often associated with longstanding, stable disease. In contrast, 5q- anomaly and the appearance of subclones in patients with an abnormal karyotype were found to be poor prognostic signs, as they are usually coincidental with evolution of the disease to myelofibrosis or leukemia. Chromosomally two patterns of acute leukemia were observed in polycythemia vera patients. The first type resembles de novo acute leukemia, in that the clinical and cytologic characteristics of the disorder are easily defined by FAB criteria and the chromosome changes compatible with the types usually found in those conditions. In the second type, assignment to a FAB morphologic subgroup was more difficult, myelodysplastic changes were often present, and the karyotype showed complex abnormalities frequently involving chromosomes #5 and #7. All these features suggest the occurrence of secondary leukemia.

Acute Disease↗
PubMed2003

Morphological, chromosomal, and molecular evolution are uncoupled in pocket mice.

C-, and G-banded chromosomes are presented for Perognathus amplus and Perognathus longimembris from Arizona, USA and Chaetodipus nelsoni from Coahuila, Mexico. The two species of Perognathus reveal similar C-band patterns, and extensive autosomal and X chromosome G-band identity with only pericentric inversions distinguishing pairs 4 and 6 and a difference in the morphology of pair 20. Three pairs of autosomal secondary constrictions were found in P. amplus and only one in P. longimembris. Only 50% of the amplus/longimembris G-banded karyotype could be aligned with that of C. nelsoni indicating extensive chromosomal restructuring has taken place since these genera last shared a common ancestor. A review of the literature suggests variable rates of morphological, chromosomal and molecular evolution in these animals.

Animals↗
PubMed2005

The human ovarian teratocarcinoma cell line PA-1 demonstrates a single translocation: analysis with fluorescence in situ hybridization, spectral karyotyping, and bacterial artificial chromosome microarray.

Cell lines derived from tumors contain numerous chromosomal aberrations and are the focus of study in tumor evolution. The ovarian teratocarcinoma cell line PA-1 demonstrates a single chromosomal aberration: a reciprocal t(15;20)(p11.2;q11.2). A complete molecular genetic analysis was undertaken to characterize this cell line. The PA-1 cell line was studied with fluorescence in situ hybridization (FISH), spectral karyotyping (SKY), bacterial artificial chromosome (BAC) microarray, and Western blotting. Amplification of 20q is frequently implicated in both breast and ovarian cancer; this region contains a number of oncogenes including MDM2, ZNF217, and the ovarian tumor marker WFDC2 (alias HE4). FISH revealed gene amplification of AIB1 (now known as NCOA3) but not STK15 (now known as AURKA). Immunoblot analysis demonstrated 3.6-fold overexpression of the AIB1 protein product, but no elevation of the STK15. BAC cancer gene microarray analysis showed gene amplification of > or =1.20 for five oncogenes. The presence of a consistent single change in PA-1, the t(15;20)(p11.2;q11.2), suggests that the aberration is significant with respect to the transformation status of the cell line. This translocation appears to cause overexpression of AIB1 (and perhaps other proteins), which may provide an immortalizing effect on this cell line.

Blotting, Western↗
PubMed2002

Comparative mapping of human Chromosome 19 with the chicken shows conserved synteny and gives an insight into chromosomal evolution.

Human Chromosome 19 (HSA19) is virtually completely sequenced. A complete physical contig map made up of BACs and cosmids is also available for this chromosome. It is, therefore, a rich source of information that we have used as the basis for a comparative mapping study with the chicken. Various orthologs of genes known to map to HSA19 have been mapped in the chicken. Five chicken microchromosomes (two of which were previously undefined) are seen to show conserved synteny with this chromosome, along with individual gene homologs on Chr 1 and another tiny microchromosome. Compared with the mouse, which has 12 chromosomal regions homologous to HSA19, the chicken genotype displays fewer evolutionary rearrangements. The ancestral nature of the chicken karyotype is demonstrated and may prove to be an excellent tool for studying genome evolution.

Animals↗