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PubMed1986

New cytogenetic techniques in the study of primate genome evolution.

Fixed metaphase chromosomes of different species and genera of Primates (five species of Macaca genus and Callithrix jacchus) have been studied after Alu I restriction enzyme digestion and DA-DAPI counterstaining, in the attempt to determine some qualitative characteristics of their DNAs and specifically of the DNA localized in the heterochromatic components of the karyotypes. The results have been discussed in the light of those already published on humans, confirming the potentiality of this approach in the study of the phyloevolutive relationships in Primates.

Animals↗

PubMed1991

Karyotypic changes associated with loss of prolactin dependency of rat Nb2 node lymphoma cell cultures.

The parent line of cultured "Nb2 node" lymphoma cells is dependent on the hormone prolactin (PRL) for growth and is widely used for the in vitro bioassay of lactogenic hormones. As reported previously, PRL-independent sublines have been developed in vitro from the parental line by lactogen deprivation. The present study describes the G-banded karyotypes of the Noble (Nb) strain of rat (in which the original lymphoma developed), the PRL-dependent cell line (157th generation), and two of its PRL-independent sublines (1220th and 2372nd generations). The karyotype of the Nb rat was determined to be the same as that of Rattus norvegicus. The stemline karyotype of the PRL-dependent cells contains a number of well-defined chromosomal abnormalities. The PRL-independent sublines examined have the same chromosomal abnormalities as the PRL-dependent cells plus a few additional changes indicative of clonal evolution from the PRL-dependent stemline. The development of PRL independence (as seen in the 1220th generation) was associated with only two karyotypic changes, i.e., loss of the Y chromosome and a translocation involving chromosomes 14 and 17. The recently reported mapping of the rat PRL gene and other PRL-related genes to chromosome 17 suggests that rearrangement of chromosome 17 could be involved in the development of the PRL independence. The PRL-dependent and PRL-independent Nb2 cell lines provide a useful system for studying chromosomal and molecular genetic events associated with the malignant progression of polypeptide hormone-dependent cancers.

Aneuploidy↗

PubMedDate not supplied

Evolutionary chromosomal differentiation among four species of Conoderus Eschscholtz, 1829 (Coleoptera, Elateridae, Agrypninae, Conoderini) detected by standard staining, C-banding, silver nitrate impregnation, and CMA3/DA/DAPI staining.

The speciose Brazilian Elateridae fauna is characterized by high karyotypic diversity, including one species (Chalcolepidius zonatus Eschscholtz, 1829) with the lowest diploid number within any Coleoptera order. Cytogenetic analysis of Conoderus dimidiatus Germar, 1839, C. scalaris (Germar, 1824,) C. ternarius Germar, 1839, and C. stigmosus Germar, 1839 by standard and differential staining was performed with the aim of establishing mechanisms of karyotypic differentiation in these species. Conoderus dimidiatus, C. scalaris, and C. ternarius have diploid numbers of 2n(male) = 17 and 2n(female) = 18, and a X0/XX sex determination system, similar to that encountered in the majority of Conoderini species. The karyotype of C. stigmosus was characterized by a diploid number of 2n = 16 and a neoXY/neoXX sex determination system that was highly differentiated from other species of the genus. Some features of the mitotic and meiotic chromosomes suggest an autosome/ancestral X chromosome fusion as the cause of the neoXY system origin in C. stigmosus. C-banding and silver impregnation techniques showed that the four Conoderus species possess similar chromosomal characteristics to those registered in most Polyphaga species, including pericentromeric C band and autosomal NORs. Triple staining techniques including CMA3/DA/DAPI also provided useful information for differentiating these Conoderus species. These techniques revealed unique GC-rich heterochromatin associated with NORs in C. scalaris and C. stigmosus and CMA3-heteromorphism in C. scalaris and C. ternarius.

Animals↗

PubMed2001

Integrative study on chromosome evolution of mammals, ants and wasps based on the minimum interaction theory.

There is well-known evidence that in many eukaryotes, different species have different karyotypes (e.g. n=1-47 in ants and n=3-51 in mammals). Alternative (fusion and fission) hypotheses have been proposed to interpret this chromosomal diversity. Although the former has long been accepted, accumulating molecular genetics evidence seems to support the latter. We investigated this problem from a stochastic viewpoint using the Monte Carlo simulation method under the minimum interaction theory. We found that the results of simulations consistently interpreted the chromosomal diversity observed in mammals, ants and wasps, and concluded that chromosome evolution tends to evolve as a whole toward increasing chromosome numbers by centric fission. Accordingly, our results support the fission hypothesis. We discussed the process of chromosome evolution based on the latest theory of the molecular structure of chromosomes, and reconfirmed that the fission burst is the prime motive force in long-term chromosome evolution, and is effective in minimizing the genetic risks due to deleterious reciprocal translocations and in increasing the potential of genetic divergence. Centric fusion plays a biological role in eliminating heterochromatin (C-bands), but is only a local reverse flow in contrast to the previously held views.

Animals↗

PubMed2004

Genome duplication in the teleost fish Tetraodon nigroviridis reveals the early vertebrate proto-karyotype.

Tetraodon nigroviridis is a freshwater puffer fish with the smallest known vertebrate genome. Here, we report a draft genome sequence with long-range linkage and substantial anchoring to the 21 Tetraodon chromosomes. Genome analysis provides a greatly improved fish gene catalogue, including identifying key genes previously thought to be absent in fish. Comparison with other vertebrates and a urochordate indicates that fish proteins have diverged markedly faster than their mammalian homologues. Comparison with the human genome suggests approximately 900 previously unannotated human genes. Analysis of the Tetraodon and human genomes shows that whole-genome duplication occurred in the teleost fish lineage, subsequent to its divergence from mammals. The analysis also makes it possible to infer the basic structure of the ancestral bony vertebrate genome, which was composed of 12 chromosomes, and to reconstruct much of the evolutionary history of ancient and recent chromosome rearrangements leading to the modern human karyotype.

Animals↗

PubMed1981

Evolution of muntjac DNA.

The extent of nuclear single-copy DNA divergence between Muntiacus reevesi and Muntiacus muntjak vaginalis (Cervidae), a species pair showing extreme karyotype differences but striking morphological similarity, is 2%, as judged from the thermal stability of interspecific DNA-DNA hybrids. A comparison of the total nuclear DNA reassociation kinetics of the two species indicates a reduction of lowly repetitive sequences in M. m. vaginalis.

Animals↗

PubMed1993

Preparation and karyotype analysis of mitotic chromosomes of the freshwater sponge Spongilla lacustris.

The present study documents for the first time the karyotype and mitotic chromosomes of a sponge. For the studies the freshwater sponge Spongilla lacustris (Lin. 1758) was used. Its karyotype comprises nine different chromosome pairs ranging in size from 2.1 to < or = 0.7 microns. Changes in size and shape of the chromosomes during the progression of mitosis are documented both light and electron microscopically. The data reveal that the lowest multicellular eukaryotes, the sponges, have already reached a high level of evolution of the mitotic mechanism.

Animals↗

PubMed2026

Eltrombopag Added to Standard Immunosuppressive Treatment as Front-Line Therapy for Severe Aplastic Anemia: Long-Term Outcomes of the Phase-3 Randomized Superiority EBMT-SAAWP RACE Study.

The RACE study (NCT02009747) compared horse antithymocyte globulin (hATG) plus cyclosporine A (CsA) ± eltrombopag as initial immunosuppressive treatment (IST) for severe aplastic anemia. Here we report the final 2-year analysis of this prospective randomized phase III study. One hundred ninety-seven treatment-naive patients were randomized to standard IST (hATG 40 mg/kg × 4 days and CsA 5 mg/kg/day; arm A; n = 101) or standard IST + eltrombopag at the dose of 150 mg/day (arm B; n = 96) from day +14 until 6 months (or 3 months, in case of complete response). The median follow-up was 23.2 months. The 2-year cumulative incidence of complete response was significantly superior in arm B (62.4% vs. 35.3%; p < 0.001). The 2-year overall survival (OS) was 86% in arm A and 91% in arm B (p = 0.081), with hazard ratio (HR), adjusted for age and disease severity, of 0.54 (p = 0.064). The 2-year disease-free survival (DFS) was 56% vs. 37% (adjusted HR = 0.49; p < 0.001), while event-free survival (EFS) was 48% vs. 32% (p < 0.001), with adjusted HR = 0.54 (p < 0.001), both significantly superior for arm B. The cumulative incidence of relapse was comparable in the two arms, while evolution to clinical paroxysmal nocturnal hemoglobinuria was 8% in arm A and 1% in arm B (p = 0.041). The risk of clonal evolution remained negligible, with one patient in arm A and two in arm B developing karyotypic abnormalities. The initial hematological response benefit of eltrombopag added to IST as front-line treatment of AA is associated with better 2-year OS, DFS, and EFS without increased risk of secondary myeloid malignancies.

Humans↗

PubMed1993

Translocation (12;14)(q13;q32) in myelodysplastic syndrome.

We report a patient diagnosed with refractory anemia with excess blasts in transformation (RAEB-t) who underwent an evolution to a nonlymphocytic acute leukemia (ANLL-M5a). Initial cytogenetic study showed a diploid karyotype; however, when ANLL-M5a was diagnosed, the bone marrow (BM) cells showed a t(12;14)(q13;q32), which to our knowledge has not been described previously in a myelodysplastic syndrome (MDS).

Anemia, Refractory, with Excess of Blasts↗

PubMed2004

No apparent reduction of gene flow in a hybrid zone between the West and North European karyotypic groups of the common shrew, Sorex araneus.

The common shrew, Sorex araneus, exhibits an unusually high level of karyotypic variation. Populations with identical or similar karyotypes are defined as chromosome races, which are, in turn, grouped into larger evolutionary units, karyotypic groups. Using six microsatellite markers, we investigated the genetic structure of a hybrid zone between the Sidensjö and Abisko chromosome races, representatives of two distinct karyotypic groups believed to have been separated during the last glacial maximum, the West European karyotypic group (western group) and the North European karyotypic group (northern group), respectively. Significant FST values among populations suggest some weak genetic structure. All hierarchical levels show similar levels of genetic differentiation, equivalent to levels of genetic structure in several intraracial studies of common shrew populations from central Europe. Notably, genetic differentiation was of the same order of magnitude between and within karyotypic groups. Although the genetic differentiation was weak, the correlation between genetic and geographical distance was positive and significant, suggesting that the genetic variation observed between populations is a function of geographical distance rather than racial origin. Hence, considerable chromosomal differences do not seem to prevent extensive gene flow.

Animals↗

PubMed2006

Multiplex-FISH (M-FISH): technique, developments and applications.

Multiplex FISH (M-FISH) represents one of the most significant developments in molecular cytogenetics of the past decade. Originally designed to generate 24 colour karyotyping, the technique has spawned many variations and an equally diverse range of applications. In tumour and leukaemia cytogenetics, the two groups that have been targeted represent both ends of the cytogenetic spectrum: those with an apparently normal karyotype (suspected of harbouring small rearrangements not detectable by conventional cytogenetics) and those with a complex aberrant karyotype (which are difficult to karyotype accurately due to the sheer number of aberrations). In research, mouse M-FISH provides a powerful tool to characterize mouse models of a disease. In addition, the ability to accurately karyotype single metaphases without selection makes M-FISH the perfect tool in chromosome breakage studies and for characterizing clonal evolution of tumours. Finally, M-FISH has emerged as the perfect partner for the developing genomic microarray (array CGH) technologies, providing a powerful approach to gene discovery.

Burkitt Lymphoma↗

PubMed1984

Clinicopathological characteristics of acute lymphoblastic leukemia with the 4;11 chromosome translocation.

Analysis of the bone marrow karyotype in 109 consecutive untreated patients with acute lymphoblastic leukemia (ALL) by the G-banding technique revealed the presence of a translocation between specific sites on the long arms of chromosomes 4 and 11, [t(4;11) (q21;q23)] in 3 adults and 2 children. Splenomegaly was present in all patients, marked leukocytosis in 4, and retinal hemorrhages in the absence of significant mucocutaneous bleeding in 3. Complete remission defined by conventional morphological criteria was achieved with combination chemotherapy in all instances, but the duration of remission was brief in 3. Three patients were studied in relapse, and clonal evolution was found to have occurred in 2. Analysis of our data in conjunction with other published reports suggests this specific karyotypic abnormality characterizes a small subgroup of ALL in which there is a strong association with recognized clinical and laboratory indices of poor prognosis, in particular its frequent occurrence in children under the age of 2.5 yr. There is a propensity to undergo clonal evolution, and the possibility exists that such a development is associated with poor prognosis.

Adolescent↗

PubMed2003

Karyotypes and cytogenetic diversity of the genus Cobitis (Pisces, Cobitidae) in Poland: a review. Cytogenetic evidence for a hybrid origin of some Cobitis triploids.

This work summarized the results of comparative chromosomal study of Cobitis fish from 13 locations in Poland. At least two distinct species C. taenia and C. elongatoides were cytogenetically recognized. The populations of C. taenia were detected in only three lakes located in northern Poland. One hybrid diploid, four triploid and four tetraploid forms were recognized among the samples. These hybrid forms or biotypes of Cobitis could not be distinguished by external characteristics. Based on the species-specific chromosome markers such as NORs, CMA3-positive and C-bands, it is hypothesized that C. taenia, C. elongatoides, and one or two other species have taken part in the origin of polyploids. Two different hybrid diploid-polyploid Cobitis complexes were distinguished. One was composed of C. taenia, two triploid hybrid forms and two tetraploids. The other complex included C. taenia and C. elongatoides, which have taken part in the origin of coexisting hybrid forms: diploid hybrid C. taenia-elongatoides, four different triploid and two tetraploid biotypes. The results obtained indicate the hypothetical mode of origin of some polyploid Cobitis forms.

Animals↗

PubMed2005

Coupling and decoupling of evolutionary mode between X- and Y-chromosomal red-green opsin genes in owl monkeys.

We previously discovered Y-chromosomal red-green opsin genes in two types of owl monkeys with different chromosomal characteristics. In one type, the Y-linked opsin gene is a single-copy intact gene and in the other, the genes exist as multiple pseudogenes on a Y/autosome fusion chromosome. In the present study, we first distinguished the two types of monkeys as distinct allopatric species on the basis of karyotypic characteristics: Aotus lemurinus griseimembra (Karyotype III, diploid chromosome number [2n]=53) and Aotus azarae boliviensis (Karyotype VI; male 2n=49; female 2n=50), belonging to the northern and southern species groups, respectively, separated by the Amazon River system. Our sequence analysis revealed a common L1-Alu-Alu insertion between the two species in the 3'-flanking region of the X-linked opsin genes. The insertion was absent in the Y-linked opsin genes and in the human red and green opsin genes, indicating that it occurred in the X copy before the split into northern and southern species and after the X to Y duplication, i.e. duplication preceded speciation. We also show that in the northern species, the Y-linked opsin gene has evolved concomitantly with the X-linked copy whereas in the southern species, the Y-autosome fusion possibly led to decoupling evolutionary processes between X- and Y-linked copies and subsequent degeneration and duplications of the Y-linked opsin gene.

Alu Elements↗

PubMed1993

Further studies of a staggered hybrid zone in Mus musculus domesticus (the house mouse).

In the extreme north-east of Scotland (near the village of John o'Groats) there is a small karyotypic race of house mouse (2n = 32), characterized by four metacentric chromosomes 4.10, 9.12, 6.13 and 11.14. We present new data on the hybrid zone between this form and the standard race (2n = 40) and show an association between race and habitat. In a transect south of John o'Groats we demonstrate that the clines for arm combinations 4.10 and 9.12 are staggered relative to the clines for 6.13 and 11.14, confirming previous data collected along an east-west transect (Searle, 1991). There are populations within the John o'Groats-standard hybrid zone dominated by individuals with 36 chromosomes (homozygous for 4.10 and 9.12), which may represent a novel karyotypic form that has arisen within the zone. Alternatively the type with 36 chromosomes may have been the progenitor of the John o'Groats race. Additional cytogenetic interest is provided by the occurrence of a homogeneous staining region on one or both copies of chromosome 1 in some mice from the zone.

Animals↗

PubMed1986

Unstable chromosome sites and evolutionary rearrangements in akodont rodents (Cricetidae).

Evolutionary rearrangements producing changes in chromosome 1 of Akodon molinae were traced by comparing the G banding patterns of the karyotypes from six species of akodont rodents. It was possible to subdivide chromosome 1 of A. molinae into unstable and stable regions. Most of the spontaneous rearrangements of chromosome 1 appearing in passages 116-128 of a continuous line of A. molinae cells (AKm line) occurred in the unstable regions which comprise repetitive DNA sequences favouring the setting up of heteroduplexes leading to rearrangements. When AKm cells were irradiated with UV light it was observed that unstable regions of chromosome 1 showed higher rates of unscheduled DNA synthesis (UD) than stable areas. A differential degree of condensation making certain regions of the chromatin fibril more accessible to repair enzymes or a better target for damage, is probably the cause of the variable response to UV light, and perhaps to most clastogenic agents (including those responsible for spontaneous rearrangements). Thus, the distribution of repetitive DNA sequences, the structure of the chromatin fibril and the efficiency of the DNA repair machinery may be important factors in the origin of spontaneous chromosomal rearrangements.

Animals↗

PubMed2001

Chromosome homologies between man and mountain zebra (Equus zebra hartmannae) and description of a new ancestral synteny involving sequences homologous to human chromosomes 4 and 8.

Using human chromosome painting probes, we looked for homologies between human and mountain zebra (Equus zebra hartmannae, Equidae, Perissodactyla) karyotypes. Except for two very short segments, all euchromatic regions were found to have a human homologous chromosome segment. Conserved syntenies previously described in various mammalian orders were detected. Each synteny corresponded to a chromosomal region homologous to two parts of human chromosomes: HSA3 and HSA21, HSA7 and HSA16, HSA12 and HSA22, and HSA16 and HSA19. Chromosomal segments homologous to a part of HSA11 and HSA19p are found syntenic in zebra, horse and donkey, suggesting that this group of synteny has been inherited from an Equidae or Perissodactyla common ancestor. A synteny of segments homologous to parts of HSA4 and HSA8 was observed in zebra and horse. It also exists in the rabbit (Lagomorpha) and several Carnivora species. A second group of taxa which does not have this region of synteny is composed of primates, Chiroptera and Insectivora, and possibly also Cetacea and Scandantia. Thus, the presence or absence of this region of synteny may separate two groups of eutherian mammals.

Animals↗

PubMed2006

Karyotypic characterization and genomic organization of the 5S rDNA in Erpetoichthys calabaricus (Osteichthyes, Polypteridae).

Polypterids are a group of Osteichthyan fish whose evolutionary relationships with closer basal ray-finned and lobe-finned fish have been disputed since their discovery. Very little is known about the evolutive karyology in the whole Polypteriformes group. In order to fill this gap, a cytogenetic analysis of Erpetoichthys calabaricus species was performed, using both classical and molecular techniques. Karyotype structure (2n = 36; FN = 72), chromosome location of telomeric sequences (TTAGGG)n and ribosomal 5S and 18S rRNA genes were examined in twenty specimens of E. calabaricus by using Ag-NOR, classical C-banding, sequential CMA3/4',6-diaminidino-2-phenylindole (DAPI) staining and fluorescent in situ hybridization (FISH). CMA3 marked all centromerical and some (no. 1 and no. 15) telomeric regions. Staining with Ag-NOR and CMA3 showed the presence of two NORs on the p arm of the chromosome pair no. 1. Hybridization with telomeric probes (TTAGGG)n showed signals at the end of all chromosomes. 5S rDNA was cloned and sequenced. After the alignment, the 5S rRNA sequences revealed an organization made up of two different classes of tandem arrays (type I and type II). FISH with 5S rDNA marked the telomeric regions of the small chromosome pair no. 15, while FISH with 18S rDNA marked the telomeric region of the pair no. 1. The results obtained were compared with cariological data on closer species now available in literature.

Animals↗