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Results for “karyotype evolution”

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PubMed1997

Distribution of highly repeated DNA sequences in species of the genus Secale.

The presence and distribution of the most important highly repetitive DNA sequences of rye in cultivated and wild species of the genus Secale were investigated using fluorescence in situ hybridization. Accurate identification of individual chromosomes in the most commonly recognized species or subspecies of the genus Secale (S. cereale, S. ancestrale, S. segetale, S. afghanicum, S. dighoricum, S. montanum, S. montanum ssp. kuprijanovii, S. africanum, S. anatolicum, S. vavilovii, and S. silvestre) was achieved using three highly repetitive rye DNA sequences (probes pSc119.2, pSc74, and pSc34) and the 5S ribosomal DNA sequence pTa794. It is difficult to superimpose trends in the complexity of repetitive DNA during the evolution of the genus on conclusions from other cytogenetic and morphological assays. However, there are two clear groups. The first comprises the self-pollinated annuals S. silvestre and S. vavilovii that have few repeated nucleotide sequences of the main families of 120 and 480 bp. The second group presents amplification and interstitialization of the repeated nucleotide sequences and includes the perennials S. montanum, S. anatolicum, S. africanum, and S. kuprijanovii, as well as the annual and open-pollinated species S. cereale and its related weedy forms. The appearance of a new locus for 5S rRNA in S. cereale and S. ancestrale suggests that cultivated ryes evolved from this wild weedy species.

Biological Evolution↗
PubMed2004

Altered specificity of Hint-W123Q supports a role for Hint inhibition by ASW in avian sex determination.

Hint is a universally conserved, dimeric AMP-lysine hydrolase encoded on the avian Z chromosome. Tandemly repeated on the female-specific W chromosome, Asw encodes a potentially sex-determining, dominant-negative Hint dimerization partner whose substrate-interacting residues were specifically altered in evolution. To test the hypothesis that Gln127 of Asw is responsible for depression and/or alteration of Hint enzyme activity, a corresponding mutant was created in the chicken Hint homodimer, and a novel substrate was developed that links reversal of AMP-lysine modification to aminomethylcoumarin release. Strikingly, the Hint-W123Q substitution reduced k(cat)/K(m) for AMP-lysine hydrolysis 17-fold, while it increased specificity for AMP-para-nitroaniline hydrolysis by 160-fold. The resulting 2,700-fold switch in enzyme specificity suggests that Gln127 could be the dominant component of Asw dominant negativity in avian feminization.

Adenosine Monophosphate↗
PubMed2006

Segmental duplication associated with evolutionary instability of human chromosome 3p25.1.

Fluorescence in situ hybridization (FISH) of human bacterial artificial chromosome (BAC) clones to orangutan metaphase spreads localized a breakpoint between human chromosome 3p25.1 and orangutan chromosome 2 to a <30-kb interval. The inversion occurred in a relatively gene-rich region with seven genes within 500 kb. The underlying breakpoint is closely juxtaposed to validated genes, however no functional gene has been disrupted by the evolutionary rearrangement. An approximately 21-kb DNA segment at the 3p25.1 breakpoint region has been duplicated intrachromosomally and interchromosomally to multiple regions in the orangutan and human genomes, providing additional evidence for the role of segmental duplications in hominoid chromosome evolution.

Animals↗
PubMed1991

[Cloning and cytogenetic localization of evolutionarily conserved genomic sequences which are expressed in the head of the Drosophila melanogaster imago].

Screening of Drosophila melanogaster genomic library was carried out using mouse brain polysomal poly(A)+RNA. As a result, 100 clones were selected, among which 14 clones were picked up after hybridization with fly head poly(A)+RNA. It follows therefore, that these clones contain evolutionary conserved sequences which are expressed in Drosophila fly heads. Analysis of these 14 clones revealed RNA-coding fragments. Comparison of their expression in heads and bodies of Drosophila was carried out. Using in situ hybridization we determined the localization of selected 14 sequences on polytene chromosomes. The possibility of further analysis of some clones to study developmental and functional processes in neural system of Drosophila is discussed.

Animals↗
PubMed1982

[Investigation of human cytogenetics for research on human evolution].

The investigation of human chromosomes has become significant in studies of evolution coincidentally with new developments in clinical cytogenetics. Banding pattern and gene mapping allow identification of individual chromosomes and chromosome parts as well as detailed comparisons between Homo sapiens and Pongidae. The most remarkable difference appears in the different diploid chromosome number, 46 in Homo sapiens and 48 in Pongidae, which can be explained through homozygous state for one translocation chromosome evolved from two acrocentric chromosomes. Chromosome rearrangements, which may have phenotypic significance because of positions effect variegations, are discussed as a mechanism of evolution. Within these species chromosomal variability may occur in the form of normal variants or polymorphic parts of chromosomes.

Animals↗
PubMed2004

A centromere-specific retroviral element associated with breaks of synteny in macropodine marsupials.

Studies of chromosome evolution have focused heavily on the evolution of conserved syntenic, gene-rich domains. It is obvious, however, that the centromere plays an equally important role in chromosome evolution, through its involvement in fissions, centric fusions, translocations, inversions and centric shifts. It is unclear how the centromere, either as a functioning unit of the chromosome or as a DNA sequence motif, has been involved in these processes. Marsupials of the family Macropodidae (kangaroos, wallabies, rat kangaroos and potoroos) offer unique insights into current theories expositing centromere emergence during karyotypic diversification and speciation. Tracing the genomic distribution of centromeric sequences in a model macropodine (subfamily Macropodinae: kangaroos and wallabies) species, Macropus eugenii (tammar wallaby), indicates these sequences have played an important role in chromosome evolution through possible segmental duplications associated with phylogenetically conserved breaks of synteny, pericentromeric and subtelomeric regions. Hybrids between different kangaroo species provide evidence that the centromere is unstable within this group of mammals and is involved in a large number of chromosome aberrations. A better understanding of the genetic and epigenetic factors that define centromeres and how centromeres may mediate changes in chromosome architecture are critical not only to our understanding of basic cellular functioning but also to our understanding of the process of speciation.

Animals↗
PubMed1978

The relevance of extramedullary hemopoiesis to the staging of chronic myeloid leukemia.

In chronic myeloid leukemia (CML) the spleen and the liver can lodge, trap and release a high proportion of leukemic cells, and are active sites of (leukemic) hemopoiesis throughout the disease. Evidence is provided that spleen and liver volume have a prognostic value, and that marrow, spleen, and liver differ as to cell composition, cell kinetic patterns, functional cell characters, and cell karyotype. In the majority of the patients, extramedullary hemopoiesis seems to be more abnormal than marrow hemopoiesis, supporting the hypothesis that spleen and/or liver can play an important role in the evolution of CML towards the blastic metamorphosis. However, present information on extramedullary hemopoiesis does not allow to identify specific patterns and to establish its relevance to the course of the disease.

Bone Marrow↗
PubMed1997

Reciprocal chromosome painting between human and prosimians (Eulemur macaco macaco and E. fulvus mayottensis).

We used fluorescence in situ hybridisation to delineate the homology between the human karyotype and those of two lemur species (Eulemur macaco macaco and E. fulvus mayottensis). Human and lemur chromosome-specific probes were established by bivariate fluorescence-activated flow sorting (FACS) and subsequent degenerate oligonucleotide-primed PCR (DOP-PCR). Reciprocal painting of human probes to lemur chromosomes and vice versa allowed a detailed analysis of the interchromosomal rearrangements that had occurred during the evolution of these species. The results indicate that the genomes of both species have undergone only a few translocations during more that 45 million years of lemur and human evolution. The synteny of homologs to human chromosomes 3, 9, 11, 13, 14, 17, 18, 20, 21, X, and Y was found to be conserved in the two lemur species. Taking non-primate mammals as the outgroup for primates, ancestral conditions for various primate chromosomes were identified and distinguished from derived forms. Lemur chromosome painting probes were also used for cross-species hybridization between the two lemur species. The results support an earlier assumption, made on the basis of chromosome banding, that the karyotypes of the two species have evolved exclusively by Robertsonian transformations. All probes derived from E. f. mayottensis chromosomes specific for homologs involved in rearrangements in E. m. macaco exclusively painted entire chromosome arms. The results further indicate that E. f. mayottensis most probably has a more ancestral karyotype than E. m. macaco. Probes derived from prosimians will be useful in comparing the karyotypes of other lower primates, which will improve our understanding of early primate genome evolution.

Animals↗
PubMed1986

Involvement of chromosomes 12 and 14 in the cutaneous stage of mycosis fungoides: cytogenetic evidence for a multistep pathogenesis of the disease.

Cytogenetic studies were performed on the cells of bone marrow, peripheral blood, and skin tumor biopsies from a patient with mycosis fungoides at an early stage. Chromosome abnormalities were detected in 100% of the cells harvested from the cutaneous specimen, whereas the cells of the bone marrow and blood were karyotypically normal. Three related clones, showing increasing cytogenetic complexity, were found. Chromosome #12 was abnormal in all metaphases, and an abnormal 14q chromosome was present in a minority of cells belonging to the most complex emerging subclone. These data, along with the findings of important signs of chromosome imbalance, suggest a polyphasic evolution of this chronic T lymphoproliferative disease.

Chromosomes, Human, 13-15↗
PubMed1988

More than two immunoglobulin heavy chain J region genes in the majority of infant leukemia.

Congenital and infant leukemia are rare conditions associated with a very poor prognosis due to the high frequency of adverse clinical and laboratory parameters. As the occurrence of multiple immunoglobulin heavy chain hybridization band in childhood leukemia has been associated with poor prognosis, we studied whether it was present in this type of leukemia as well. Seven cases were examined, 4 of them less than 7 months of age. The immunophenotype was lymphoid in 5 and hybrid in 2. Most had abnormal karyotypes. In 5 of the 7, including all with congenital leukemia, an immunoglobulin heavy chain J region multiband pattern was found by Southern blot. The multiband pattern, whether primary or due to clonal evolution, seems to be associated with poor prognosis.

Adolescent↗
PubMed1985

Suppression of clonal evolution in two chronic myelogenous leukaemia patients treated with leucocyte interferon.

Two patients with Philadelphia chromosome-positive (Ph1+) chronic myelogenous leukaemia (CML) were treated with human leucocyte interferon (HuIFN-alpha). Karyotypic changes in addition to the Ph1 chromosome developed in these patients before the start of HuIFN-alpha treatment. In one patient the administration of HuIFN-alpha resulted in clinical haematological remission and stable suppression of the secondary Ph1 clone. The second patient was in myeloid blastic crisis when given HuIFN-alpha. While she was receiving HuIFN-alpha, suppression of the blast cell population in the bone marrow occurred. The subsequent cytogenetic changes included a near-complete suppression of a secondary Ph 1 clone of cells carrying a deletion in the short arm of chromosome 7 and partial population of the bone marrow with primary Ph1 clone. These observations suggest a potential role for interferons in altering the progressive course of CML.

Adult↗
PubMed2001

Morphologically differentiated sex chromosomes in neotropical freshwater fish.

A general survey of the occurrence of morphologically differentiated sex chromosomes in the neotropical freshwater fishes is presented. The total number of 32 occurrences involving simple XX-XY and ZZ-ZW, and multiple X1X2Y, XY1Y2 and ZW1W2 sex chromosome systems is described, with comments on the aspects of sex chromosome evolution in this fish fauna. The occurrence of different sex chromosome systems in related species of the same genus, or in different populations of the same nominal species, involving male and sometimes female heterogamety, and differences in the molecular composition of sex-linked heterochromatin, are considered as indicative of the early stage of sex chromosomes evolution in fish.

Animals↗
PubMed2002

Application of multicolor fluorescence in situ hybridization analysis for detection of cross-contamination and in vitro progression in commonly used murine tumor cell lines.

Murine tumor models are potent tools for cancer studies, most of which make use of a limited number of murine tumor cell lines that are exchanged by many research groups around the world. Although cross-contamination and in vitro karyotypic progression are well-known risks with respect to the identity of tumor cell lines, these parameters are rarely evaluated. Notably, routine karyotyping of murine cell lines is laborious and technically demanding because mouse chromosomes are morphologically similar. We therefore used a 21-color fluorescence in situ hybridization (FISH) approach (COBRA) for screening two groups of frequently used murine tumor cell lines, each of which shares known immunologic determinants. Multicolor analysis revealed that the sharing of immunologic determinants among three murine lymphoma cell lines (EL-4, MBL-2, and RBL-5) is directly related to their common origin. In several of the cell lines, the chromosomal derivatives had rearranged further, suggesting that the cross-contamination events were not recent. In contrast, karyotypic analysis of three murine colon cancer cell lines (C26, CC36, and C51) showed that these constituted independent tumor clones despite the sharing of immunologic determinants. Our data point out that cross-contamination and in vitro evolution of murine tumor cell lines are a common phenomenon, and that multicolor FISH analysis is an efficient tool for verifying the origin and tracking the evolution of murine cell lines.

Adenocarcinoma↗
PubMed1996

A case of acute myelofibrosis with complex karyotypic changes: a type of myelodysplastic syndrome.

A 73-year-old woman developed a rapidly fatal disease that fit the clinical criteria for acute myelofibrosis. Over a 9 month period she progressed from normal peripheral blood counts to severe pancytopenia and finally a terminal phase with monocytosis and circulating myeloblasts. Morphologic examination of her bone marrow at presentation showed trilineage dysplasia, hypercellularity, and diffuse fibrosis with foci of immature precursors. Cytogenetic, analysis showed the karyotype 45-46, XX,del(5)(q33),+11,add(17)(q25),-18,-20,+22. The morphologic and cytogenetic findings in this case support a relationship between acute myelofibrosis and myelodysplastic syndromes. Acute myelofibrosis with complex chromosomal aberrations may represent one pathway of evolution in myelodysplasia that is associated with a particularly poor prognosis.

Acute Disease↗