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199 records returned

Complex genomic organization of Indian muntjac centromeric DNA.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A 69-kb Indian muntjac bacterial artificial chromosome (BAC) clone that screened positive for Cervid satellites I and IV was selected for complete sequence analysis and further characterization. The sequences of this BAC clone were found in the centromeres and in some interstitial sites of Indian muntjac chromosomes. Sequence analyses showed that the BAC clone contained a 14.5 kb Cervid satellite I-like DNA element and a 9 kb Cervid satellite IV-like DNA element. In addition, it contained 51 regions each organized in a complex fashion, with sequences homology to intersperse repetitive sequences such as LINEs, SINEs, LT...
Source: Chromosome Research - November 18, 2009 Category: Genetics & Stem Cells Authors: Cheng YM, Li TS, Hsieh LJ, Hsu PC, Li YC, Lin CC Tags: Chromosome Res Source Type: journals

Genome-wide approaches to determining origin distribution.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Genome integrity depends upon a highly co-ordinated process that ensures the exact duplication of the genome at each cell cycle. Genomic mapping of DNA replication starting points in mammals, known as origins of replication, is an important step towards our understanding of how this essential mechanism is regulated throughout complex genomes. Two recent studies carried out in both human and mouse cells have revealed a strong association between replication origins and transcriptional regulatory elements. This strong overlap raises the question of how gene deserts, also lacking replication origins, are properly replicat...
Source: Chromosome Research - November 18, 2009 Category: Genetics & Stem Cells Authors: Cadoret JC, Prioleau MN Tags: Chromosome Res Source Type: journals

Why are we where we are? Understanding replication origins and initiation sites in eukaryotes using ChIP-approaches.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
DNA replication initiates from origins of replication following a strict sequential activation programme and a conserved temporal order of activation. The number of replication initiation sites varies between species, according to the complexity of the genomes, with an average spacing of 100,000 bp. In contrast to yeast genomes, the location and definition of origins in mammalian genomes has been elusive. Historically, mammalian replication initiation sites have been mapped in situ by systematically searching specific genomic loci for sites that preferentially initiated DNA replication, potential origins by start-site ...
Source: Chromosome Research - November 11, 2009 Category: Genetics & Stem Cells Authors: Schepers A, Papior P Tags: Chromosome Res Source Type: journals

Genetic variation exists for telomeric array organization within and among the genomes of normal, immortalized, and transformed chicken systems.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This study investigated telomeric array organization of diverse chicken genotypes utilizing in vivo and in vitro cells having phenotypes with different proliferation potencies. Our experimental objective was to characterize the extent and nature of array variation present to explore the hypothesis that mega-telomeres are a universal and fixed feature of chicken genotypes. Four different genotypes were studied including normal (UCD 001, USDA-ADOL Line 0), immortalized (DF-1), and transformed (DT40) cells. Both cytogenetic and molecular approaches were utilized to develop an integrated view of telomeric array organization. I...
Source: Chromosome Research - November 5, 2009 Category: Genetics & Stem Cells Authors: O'Hare TH, Delany ME Tags: Chromosome Res Source Type: journals

A winding road to origin discovery.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Studies in our laboratory over the last three decades have shown that the Chinese hamster dihydrofolate reductase (DHFR) origin of replication corresponds to a broad zone of inefficient initiation sites distributed throughout the spacer between the convergently transcribed DHFR and 2BE2121 genes. It is clear from mutational analysis that none of these sites is genetically required for controlling origin activity. However, the integrity of the promoter of the DHFR gene is needed to activate the downstream origin, while the 3' processing signals prevent invasion and inactivation of the downstream origin by transcription ...
Source: Chromosome Research - October 27, 2009 Category: Genetics & Stem Cells Authors: Hamlin JL, Mesner LD, Dijkwel PA Tags: Chromosome Res Source Type: journals

Spatial regulation and organization of DNA replication within the nucleus.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Duplication of chromosomal DNA is a temporally and spatially regulated process. The timing of DNA replication initiation at various origins is highly coordinated; some origins fire early and others late during S phase. Moreover, inside the nuclei, the bulk of DNA replication is physically organized in replication factories, consisting of DNA polymerases and other replication proteins. In this review article, we discuss how DNA replication is organized and regulated spatially within the nucleus and how this spatial organization is linked to temporal regulation. We focus on DNA replication in budding yeast and fission ye...
Source: Chromosome Research - October 24, 2009 Category: Genetics & Stem Cells Authors: Natsume T, Tanaka TU Tags: Chromosome Res Source Type: journals

Higher axial-resolution and sensitivity pachytene fluorescence in situ hybridization protocol in tetraploid cotton.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, the first protocol developed for pachytene chromosome preparation in tetraploid cotton is presented. This protocol yielded chromosome spreads suitable for large and small DNA probe FISH labeling. Two important parameters, axial-resolution and sensitivity, of FISH on mitotic metaphase and pachytene chromosomes were systematically analyzed. The results demonstrated that DNA targets separated by 0.6 cM and low-copy targets as small as 3-kb were resolved and detected, respectively, in pachytene FISH. The application of our FISH protocol will continue to improve and provide a point of departure for constructing a...
Source: Chromosome Research - October 20, 2009 Category: Genetics & Stem Cells Authors: Wang K, Yang Z, Shu C, Hu J, Lin Q, Zhang W, Guo W, Zhang T Tags: Chromosome Res Source Type: journals

Sequence map of the 3-Mb Giardia duodenalis assemblage A chromosome.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The genome of the gut protozoan parasite Giardia duodenalis (assemblage A) has been sequenced and compiled as contigs and scaffolds (GiardiaDB- http://GiardiaDB.org ), but specific chromosome location of all scaffolds is unknown. To determine which scaffolds belong to the 3-Mb chromosome, a library of probes specific for this chromosome was constructed. The probes were hybridised to NotI-cleaved whole chromosomes, and the combined size of different NotI segments identified by the probes was 2,225 kb indicating the probes were well distributed along the 3-Mb chromosome. Six scaffolds (CH991814, CH991779, CH991793, CH991...
Source: Chromosome Research - October 15, 2009 Category: Genetics & Stem Cells Authors: Upcroft JA, Krauer KG, Burgess AG, Dunn LA, Chen N, Upcroft P Tags: Chromosome Res Source Type: journals

X chromosomal regulation in flies: when less is more.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In Drosophila, dosage compensation of the single male X chromosome involves upregulation of expression of X linked genes. Dosage compensation complex or the male specific lethal (MSL) complex is intimately involved in this regulation. The MSL complex members decorate the male X chromosome by binding on hundreds of sites along the X chromosome. Recent genome wide analysis has brought new light into X chromosomal regulation. It is becoming increasingly clear that although the X chromosome achieves male specific regulation via the MSL complex members, a number of general factors also impinge on this regulation. Future stu...
Source: Chromosome Research - October 8, 2009 Category: Genetics & Stem Cells Authors: Hallacli E, Akhtar A Tags: Chromosome Res Source Type: journals

The worm solution: a chromosome-full of condensin helps gene expression go down.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Dosage compensation in the nematode Caenorhabditis elegans is achieved by the binding of a condensin-like dosage compensation complex (DCC) to both X chromosomes in hermaphrodites to downregulate gene expression two-fold. Condensin I(DC), a sub-part of the DCC, differs from the mitotic condensin I complex by a single subunit, strengthening the connection between dosage compensation and mitotic chromosome condensation. The DCC is targeted to X chromosomes by initial binding to a number of recruiting elements, followed by dispersal or spreading to secondary sites. While the complex is greatly enriched on the X chromosome...
Source: Chromosome Research - October 8, 2009 Category: Genetics & Stem Cells Authors: Csankovszki G, Petty EL, Collette KS Tags: Chromosome Res Source Type: journals

Dosage compensation and gene expression on the mammalian X chromosome: one plus one does not always equal two.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Counting chromosomes is not just simple math. Although normal males and females differ in sex chromosome content (XY vs. XX), X chromosome imbalance is tolerated because dosage compensation mechanisms have evolved to ensure functional equivalence. In mammals this is accomplished by two processes--X chromosome inactivation that silences most genes on one X chromosome in females, leading to functional X monosomy for most genes in both sexes, and X chromosome upregulation that results in increased gene expression on the single active X in males and females, equalizing dosage relative to autosomes. This review focuses on g...
Source: Chromosome Research - October 8, 2009 Category: Genetics & Stem Cells Authors: Prothero KE, Stahl JM, Carrel L Tags: Chromosome Res Source Type: journals

Monosomy for the X chromosome.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This article reviews observations and arguments attempting to explain the phenotypic effects of X monosomy in humans and other mammals in terms of X chromosome gene dosage. PMID: 19802705 [PubMed - in process] (Source: Chromosome Research)
Source: Chromosome Research - October 8, 2009 Category: Genetics & Stem Cells Authors: Bondy CA, Cheng C Tags: Chromosome Res Source Type: journals

Lessons from comparative analysis of X-chromosome inactivation in mammals.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In most mammals, X-chromosome inactivation is used as the strategy to achieve dosage compensation between XX females and XY males. This process is developmentally regulated, resulting in the differential treatment of the two X chromosomes in the same nucleus and mitotic heritability of the silent state. A lack of dosage compensation in an XX embryo is believed to result in early lethality, at least in eutherians. Given its fundamental importance, X-chromosome inactivation would be predicted to be a highly conserved process in mammals. However, recent studies have revealed major mechanistic differences in X inactivation...
Source: Chromosome Research - October 8, 2009 Category: Genetics & Stem Cells Authors: Okamoto I, Heard E Tags: Chromosome Res Source Type: journals

Unravelling the evolutionary origins of X chromosome inactivation in mammals: insights from marsupials and monotremes.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Determining the evolutionary origin of X inactivation mechanisms in mammals requires knowledge of features of X inactivation across all three major mammal lineages; monotremes, marsupials and eutherians. In the past, research into X inactivation in marsupials and monotremes lagged far behind the major advances made in understanding the mechanisms of X inactivation in human and mouse. Fragmentary knowledge of the genic content and sequence of marsupial and monotreme X chromosomes has been alleviated by the recent release of genome sequences for two marsupials and one monotreme. This has lead to a number of important fin...
Source: Chromosome Research - October 8, 2009 Category: Genetics & Stem Cells Authors: Deakin JE, Chaumeil J, Hore TA, Marshall Graves JA Tags: Chromosome Res Source Type: journals

Avian sex chromosomes: dosage compensation matters.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In 2001 it was established that, contrary to our previous understanding, a mechanism exists that equalises the expression levels of Z chromosome genes found in male (ZZ) and female (ZW) birds (McQueen et al. 2001). More recent large scale studies have revealed that avian dosage compensation is not a chromosome-wide phenomenon and that the degree of dosage compensation can vary between genes (Itoh et al. 2007; Ellegren et al. 2007). Although, surprisingly, dosage compensation has recently been described as absent in birds (Mank and Ellegren 2009b), this interpretation is not supported by the accumulated evidence, which ...
Source: Chromosome Research - October 8, 2009 Category: Genetics & Stem Cells Authors: McQueen HA, Clinton M Tags: Chromosome Res Source Type: journals

Gene and genome duplications: the impact of dosage-sensitivity on the fate of nuclear genes.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Whole genome duplications (WGDs) followed by diploidization, which includes gene loss, have been an important recurrent process in the evolution of higher eukaryotes. Gene retention is biased to specific functional gene categories during diploidization. Dosage-sensitive genes, which include transcription factors, are significantly over-retained following WGDs. By contrast, these same functional gene categories exhibit lower retention rates following smaller scale duplications (e.g., local and tandem duplicates, segmental duplicates, aneuploidy). In light of these recent observations, we review current theories that add...
Source: Chromosome Research - October 8, 2009 Category: Genetics & Stem Cells Authors: Edger PP, Pires JC Tags: Chromosome Res Source Type: journals

Extensive conservation of genomic imbalances in canine transmissible venereal tumors (CTVT) detected by microarray-based CGH analysis.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We present characterization of a strategically selected panel of CTVT cases using microarray-based comparative genomic hybridization analysis at ~one-megabase resolution. These data show for the first time that the tumor presents with an extensive range of non-random chromosome copy number aberrations that are distributed widely throughout the dog genome. The majority of abnormalities detected were imbalances of small subchromosomal regions, often involving centromeric and telomeric sequences. All cases also showed the sex chromosome complement XO. There was remarkable conservation in the cytogenetic profiles of the tumors...
Source: Chromosome Research - September 29, 2009 Category: Genetics & Stem Cells Authors: Thomas R, Rebbeck C, Leroi AM, Burt A, Breen M Tags: Chromosome Res Source Type: journals

Physical mapping of the elephant X chromosome: conservation of gene order over 105 million years.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
All therian mammals (eutherians and marsupials) have an XX female/XY male sex chromosome system or some variant of it. The X and Y evolved from a homologous pair of autosomes over the 166 million years since therian mammals diverged from monotremes. Comparing the sex chromosomes of eutherians and marsupials defined an ancient X conserved region that is shared between species of these mammalian clades. However, the eutherian X (and the Y) was augmented by a recent addition (XAR) that is autosomal in marsupials. XAR is part of the X in primates, rodents, and artiodactyls (which belong to the eutherian clade Boreoeutheria...
Source: Chromosome Research - September 29, 2009 Category: Genetics & Stem Cells Authors: Rodríguez Delgado CL, Waters PD, Gilbert C, Robinson TJ, Graves JA Tags: Chromosome Res Source Type: journals

The choanoflagellate Monosiga brevicollis karyotype revealed by the genome sequence: Telomere-linked helicase genes resemble those of some fungi.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The approximately 42 Mbp assembled genome sequence for the choanoflagellate Monosiga brevicollis reveals that most of the large scaffolds of 300-2,600 kb represent entire chromosomes or chromosome arms. Telomeres are partially assembled at the termini of 37 scaffolds, while another 43 scaffolds end in telomere-associated regions containing distinctive gene sets. Potential centromeric regions were identified on 39 scaffolds. Together, these observations suggest a karyotype of approximately 40 metacentric and submetacentric chromosomes averaging 1 Mbp in size. Genes encoding RecQ family DNA helicases, along with ankyrin-...
Source: Chromosome Research - September 29, 2009 Category: Genetics & Stem Cells Authors: Robertson HM Tags: Chromosome Res Source Type: journals

Dm nxf1/sbr gene affects the formation of meiotic spindle in female Drosophila melanogaster.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The small bristles (sbr) gene of Drosophila melanogaster belongs to the family of nuclear export factor (NXF) genes that participate in mRNA nuclear export. During meiosis, females of Drosophila melanogaster that carry various combinations of mutant alleles of the Dm nxf1/sbr gene exhibit disruption of the division spindle and misalignment of chromosomes at the metaphase plate. Meiosis of sbr ( 5 ) /+ females is characterized by the formation of tripolar spindles during the first cell division. According to the sequencing results, the sbr ( 5 ) (l(1)K4) lethal allele is a deletion of 492 nucleotides. In SBR(5) protein,...
Source: Chromosome Research - September 24, 2009 Category: Genetics & Stem Cells Authors: Golubkova EV, Markova EG, Markov AV, Avanesyan EO, Nokkala S, Mamon LA Tags: Chromosome Res Source Type: journals

Assignment of genetic linkage maps to diploid Solanum tuberosum pachytene chromosomes by BAC-FISH technology.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A cytogenetic map has been developed for diploid potato (Solanum tuberosum), in which the arms of the 12 potato bivalents can be identified in pachytene complements using multicolor fluorescence in situ hybridization (FISH) with a set of 60 genetically anchored bacterial artificial chromosome (BAC) clones from the RHPOTKEY BAC library. This diagnostic set of selected BACs (five per chromosome) hybridizes to euchromatic regions and corresponds to well-defined loci in the ultradense genetic map, and with these probes a new detailed and reliable pachytene karyotype could be established. Chromosome size has been estimated ...
Source: Chromosome Research - September 22, 2009 Category: Genetics & Stem Cells Authors: Tang X, de Boer JM, van Eck HJ, Bachem C, Visser RG, de Jong H Tags: Chromosome Res Source Type: journals

Molecular characterization of a putative heat shock protein cognate gene in Rhynchosciara americana.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
An hsc70 homologue gene (Rahsc70) of the diptera Rhynchosciara americana was isolated and characterized. We were able to determine the mRNA sequence from an EST of salivary gland cDNA library, and a Rahsc70 cDNA cassette was used as a probe to isolate the genomic region from a genomic library. The mRNA expression of this gene parallels the 2B puff expansion, suggesting its involvement in protein processing, since this larval period corresponds to a high synthetic activity period. During heat shock stress conditions, hsc70 expression decreased. In situ hybridization of polytene chromosomes showed that the Rahsc70 gene i...
Source: Chromosome Research - September 18, 2009 Category: Genetics & Stem Cells Authors: de Andrade A, Siviero F, Rezende-Teixeira P, Santelli RV, Machado-Santelli GM Tags: Chromosome Res Source Type: journals

Potential sites of triple-helical nucleic acid formation in chromosomes of Rhynchosciara (Diptera: Sciaridae) and Drosophila melanogaster.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Antibodies to specific nucleic acid conformations are amongst the methods that have allowed the study of non-canonical (Watson-Crick) DNA structures in higher organisms. In this work, the structural limitations for the immunological detection of DNA.RNA hybrid duplexes were examined using specific RNA homopolymers as probes for homopolymer polydeoxyadenylic acid (poly(dA)).polydeoxythymidylic acid (poly(dT))-rich regions of Rhynchosciara americana (Diptera: Sciaridae) chromosomes. Anti-DNA.RNA duplexes did not react with the complex formed between chromosomal poly(dA) and exogenous polyuridylic acid (poly(rU)). Additio...
Source: Chromosome Research - September 17, 2009 Category: Genetics & Stem Cells Authors: Gorab E, Amabis JM, Stocker AJ, Drummond L, Stollar BD Tags: Chromosome Res Source Type: journals

Nuclear architecture of resting and LPS-stimulated porcine neutrophils by 3D FISH.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Neutrophils are essential components of the innate immune system due to their ability to kill and phagocytose invading microbes. They possess a lobulated nucleus and are capable of extensive and complex changes in response to bacterial stimulation. The aim of our study was to investigate whether the 3D nuclear organization of porcine neutrophils was modified upon stimulation. The organization of centromeres, telomeres, and chromosome territories (chromosomes 2, 3, 7, 8, 12, 13, and 17) was studied on structurally preserved nuclei using 3D fluorescence in situ hybridization, confocal microscopy, and image analysis. By d...
Source: Chromosome Research - September 17, 2009 Category: Genetics & Stem Cells Authors: Yerle-Bouissou M, Mompart F, Iannuccelli E, Robelin D, Jauneau A, Lahbib-Mansais Y, Delcros C, Oswald IP, Gellin J Tags: Chromosome Res Source Type: journals

Unstable transmission of rice chromosomes without functional centromeric repeats in asexual propagation.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, we observed that the extra short arm of chromosome 8 (.8S) can easily be lost in the telotrisomic, and we determined by fluorescence in-situ hybridization (FISH) analysis that the centromeric region of the extra .8S did not contain the rice centromeric satellite repeat (CentO) and centromere-specific retrotransposon (CRR); however, the extra .8S contained part of the CentO and CRR sequences in the initially preserved telotrisomic line. We confirmed by real-time quantitative PCR (RQ-PCR) analysis that the original functional centromere of the extra .8S was lost. Using both FISH and RQ-PCR, the breakage point ...
Source: Chromosome Research - September 14, 2009 Category: Genetics & Stem Cells Authors: Gong Z, Yu H, Huang J, Yi C, Gu M Tags: Chromosome Res Source Type: journals

Enrichment of brain-related genes on the mammalian X chromosome is ancient and predates the divergence of synapsid and sauropsid lineages.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Previous studies have revealed an enrichment of reproduction- and brain-related genes on the human X chromosome. In the present study, we investigated the evolutionary history that underlies this functional specialization. To do so, we analyzed the orthologous building blocks of the mammalian X chromosome in the chicken genome. We used Affymetrix chicken genome microarrays to determine tissue-selective gene expression in several tissues of the chicken, including testis and brain. Subsequently, chromosomal distribution of genes with tissue-selective expression was determined. These analyzes provided several new findings...
Source: Chromosome Research - September 3, 2009 Category: Genetics & Stem Cells Authors: Kemkemer C, Kohn M, Kehrer-Sawatzki H, Fundele RH, Hameister H Tags: Chromosome Res Source Type: journals

Revealing the high-resolution three-dimensional network of chromatin and interchromatin space: A novel electron-microscopic approach to reconstructing nuclear architecture.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The nuclear architecture is considered an important contributor to genome function. Although the fine structural features of the cell nucleus have been investigated extensively by means of ultrastructural cytochemistry, mainly on ultrathin sections in two dimensions (2D), there was a of lack routine methods for a rapid reconstruction of three-dimensional (3D) distribution of different structural constituents throughout the nuclear volume. We have now filled this gap by the application of a novel approach associating a pre-embedding selective visualization of nuclear components with a method making use of ultramicrotomy...
Source: Chromosome Research - September 3, 2009 Category: Genetics & Stem Cells Authors: Rouquette J, Genoud C, Vazquez-Nin GH, Kraus B, Cremer T, Fakan S Tags: Chromosome Res Source Type: journals

Karyotypic relationships in Asiatic asses (kulan and kiang) as defined using horse chromosome arm-specific and region-specific probes.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Cross-species chromosome painting has been applied to most of the species making up the numerically small family Equidae. However, comparative mapping data were still lacking in Asiatic asses kulan (Equus hemionus kulan) and kiang (E. kiang). The set of horse arm-specific probes generated by laser microdissection was hybridized onto kulan (E. hemionus kulan) and kiang (E. kiang) chromosomes in order to establish a genome-wide chromosomal correspondence between these Asiatic asses and the horse. Moreover, region-specific probes were generated to determine fusion configuration and orientation of conserved syntenic blocks...
Source: Chromosome Research - September 3, 2009 Category: Genetics & Stem Cells Authors: Musilova P, Kubickova S, Horin P, Vodička R, Rubes J Tags: Chromosome Res Source Type: journals

FISH and DAPI staining of the synaptonemal complex of the Nile tilapia (Oreochromis niloticus) allow orientation of the unpaired region of bivalent 1 observed during early pachytene.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Bivalent 1 of the synaptonemal complex (SC) in XY male Oreochromis niloticus shows an unpaired terminal region in early pachytene. This appears to be related to recombination suppression around a sex determination locus. To allow more detailed analysis of this, and unpaired regions in the karyotype of other Oreochromis species, we developed techniques for FISH on SC preparations, combined with DAPI staining. DAPI staining identified presumptive centromeres in SC bivalents, which appeared to correspond to the positions observed in the mitotic karyotype (the kinetochores could be identified only sporadically in silver-st...
Source: Chromosome Research - August 27, 2009 Category: Genetics & Stem Cells Authors: Ocalewicz K, Mota-Velasco JC, Campos-Ramos R, Penman DJ Tags: Chromosome Res Source Type: journals

Functional analysis of Drosophila polytene chromosomes decompacted unit: the interband.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Differential compaction of the interphase chromosomes is important for proper functioning of the eukaryotic genome. Such non-uniform compaction is most easily observed in Drosophila salivary gland polytene chromosomes as a reproducible banding pattern. Functional mechanisms underlying the establishment and maintenance of the banding pattern remain unclear but have been hypothesized to involve transcription and chromatin insulators. We tested functional properties of DNA fragments from several transcriptionally inert interband regions that behave as autonomous decompacted units of polytene chromosomes. Our results sugge...
Source: Chromosome Research - August 20, 2009 Category: Genetics & Stem Cells Authors: Berkaeva M, Demakov S, Schwartz YB, Zhimulev I Tags: Chromosome Res Source Type: journals

Characterization of the two centromeric proteins CENP-C and MIS12 in Nicotiana species.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, we isolated and characterized cDNAs encoding two centromeric proteins CENP-C and MIS12 from Nicotiana tabaccum. Two CENP-C homologues, NtCENP-C-1 and -2, isolated from N. tabaccum were similar to CENP-C from N. sylvestris and N. tomentosiformis, respectively. Similarly, two Mis12 homologues, NtMIS12-1 and -2, in N. tabaccum were shown to originate from N. sylvestris and N. tomentosiformis, respectively. Both respective homologues for CENP-C and Mis12 were expressed at the same level. This indicates that in a tetraploid species, N. tabaccum, two ancestral genes encoding the centromeric proteins participate eq...
Source: Chromosome Research - August 20, 2009 Category: Genetics & Stem Cells Authors: Nagaki K, Kashihara K, Murata M Tags: Chromosome Res Source Type: journals

Premature chromatid separation is not a useful diagnostic marker for Cornelia de Lange syndrome.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Cornelia de Lange syndrome (CdLS) is a rare, multiple congenital anomaly/mental retardation syndrome characterized by clinical variability and caused by mutations in the NIPBL (50-60%), SMC1L1 and SMC3 genes (5%), which encode for proteins involved in sister chromatid cohesion. Almost all of the studies of premature chromatid separation (PCS) in CdLS patients have failed to demonstrate that it is specific to CdLS, thus making its diagnostic use controversial. In order to verify the diagnostic usefulness of PCS screening in CdLS, we analysed metaphase spreads from 29 CdLS patients and 24 controls using a rigorous protoc...
Source: Chromosome Research - August 18, 2009 Category: Genetics & Stem Cells Authors: Castronovo P, Gervasini C, Cereda A, Masciadri M, Milani D, Russo S, Selicorni A, Larizza L Tags: Chromosome Res Source Type: journals

Comparative cytogenetics of cichlid fishes through genomic in-situ hybridization (GISH) with emphasis on Oreochromis niloticus.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, we compare the genome of O. niloticus with that of other cichlids from Africa and South America using genomic in-situ hybridization (GISH). Our results show that at least some elements comprising the pericentromeric heterochromatin of Nile tilapia are species-specific and that the sequence of the majority of the long arm of the largest chromosome pair is conserved within the tilapiine group, which is composed of the genera Tilapia, Oreochromis, and Sarotherodon. It is suggested that the extensive regions of repeated DNA in the largest chromosome pair of O. niloticus resulted from chromosome rearrangement or ...
Source: Chromosome Research - August 14, 2009 Category: Genetics & Stem Cells Authors: Targino Valente G, Henrique Schneider C, Claudia Gross M, Feldberg E, Martins C Tags: Chromosome Res Source Type: journals

The role of LINEs and CpG islands in dosage compensation on the chicken Z chromosome.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Most avian Z genes are expressed more highly in ZZ males than ZW females, suggesting that chromosome-wide mechanisms of dosage compensation have not evolved. Nevertheless, a small percentage of Z genes are expressed at similar levels in males and females, an indication that a yet unidentified mechanism compensates for the sex difference in copy number. Primary DNA sequences are thought to have a role in determining chromosome gene inactivation status on the mammalian X chromosome. However, it is currently unknown whether primary DNA sequences also mediate chicken Z gene compensation status. Using a combination of chick...
Source: Chromosome Research - August 11, 2009 Category: Genetics & Stem Cells Authors: Melamed E, Arnold AP Tags: Chromosome Res Source Type: journals

Implication of long-distance regulation of the HOXA cluster in a patient with postaxial polydactyly.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Apparently balanced chromosomal inversions may lead to disruption of developmentally important genes at the breakpoints of the inversion, causing congenital malformations. Characterization of such inversions may therefore lead to new insights in human development. Here, we report on a de novo inversion of chromosome 7 (p15.2q36.3) in a patient with postaxial polysyndactyly. The breakpoints do not disrupt likely candidate genes for the limb phenotype observed in the patient. However, on the p-arm the breakpoint separates the HOXA cluster from a gene desert containing several conserved noncoding elements, suggesting that...
Source: Chromosome Research - August 11, 2009 Category: Genetics & Stem Cells Authors: Lodder EM, Eussen BH, van Hassel DA, Hoogeboom AJ, Poddighe PJ, Coert JH, Oostra BA, de Klein A, de Graaff E Tags: Chromosome Res Source Type: journals

A novel, simple and rapid nondenaturing FISH (ND-FISH) technique for the detection of plant telomeres. Potential used and possible target structures detected.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We report a new technique-nondenaturing FISH (ND-FISH)-for the rapid detection of plant telomeres without the need for prior denaturation of the chromosomes. In its development, two modified, synthetic oligonucleotides, 21 nt in length, fluorescently labelled at their 5' and 3' ends and complementary to either the cytidine-rich (C(3)TA(3)) or guanosine-rich (T(3)AG(3)) telomeric DNA strands, were used as probes. The high binding affinity of these probes and the short hybridization time required allows the visualization of plant telomeres in less than an hour. In tests, both probes gave strong signals visualized as double s...
Source: Chromosome Research - August 10, 2009 Category: Genetics & Stem Cells Authors: Cuadrado A, Golczyk H, Jouve N Tags: Chromosome Res Source Type: journals

Quantum dots as new-generation fluorochromes for FISH: an appraisal.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In the field of nanotechnology, quantum dots (QDs) are a novel class of inorganic fluorochromes composed of nanometre-scale crystals made of a semiconductor material. Given the remarkable optical properties that they possess, they have been proposed as an ideal material for use in fluorescent in-situ hybridization (FISH). That is, they are resistant to photobleaching and they excite at a wide range of wavelengths but emit light in a very narrow band that can be controlled by particle size and thus have the potential for multiplexing experiments. The principal aim of this study was to compare the potential of QDs agains...
Source: Chromosome Research - July 30, 2009 Category: Genetics & Stem Cells Authors: Ioannou D, Tempest HG, Skinner BM, Thornhill AR, Ellis M, Griffin DK Tags: Chromosome Res Source Type: journals

Progress and prospects toward our understanding of the evolution of dosage compensation.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In many eukaryotic organisms, gender is determined by a pair of heteromorphic sex chromosomes. Degeneration of the non-recombining Y chromosome is a general facet of sex chromosome evolution. Selective pressure to restore expression levels of X-linked genes relative to autosomes accompanies Y-chromosome degeneration, thus driving the evolution of dosage compensation mechanisms. This review focuses on evolutionary aspects of dosage compensation, in light of recent advances in comparative and functional genomics that have substantially increased our understanding of the molecular mechanisms of dosage compensation and how...
Source: Chromosome Research - July 22, 2009 Category: Genetics & Stem Cells Authors: Vicoso B, Bachtrog D Tags: Chromosome Res Source Type: journals

Interspecific transfer of mammalian artificial chromosomes between farm animals.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study we have tested the hypothesis that centromeric DNA sequence similarity could be a useful criterion for determining MAC host range. Homology studies indicated that the sheep should give positive transfer results. The prediction was tested by introducing into sheep cells a yeast artificial chromosome that contained swine centromeric sequences and that had previously been used to produce a de novo MAC in swine cells. The experiments resulted in the formation of a functional de novo MAC in sheep cells, as attested by FISH analysis. The newly formed MAC remained structurally and functionally stable in ovine up to ...
Source: Chromosome Research - July 22, 2009 Category: Genetics & Stem Cells Authors: Cavaliere FM, Scoarughi GL, Cimmino C Tags: Chromosome Res Source Type: journals

Plenary lectures.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Authors: PMID: 19575300 [PubMed - as supplied by publisher] (Source: Chromosome Research)
Source: Chromosome Research - July 2, 2009 Category: Genetics & Stem Cells Tags: Chromosome Res Source Type: journals

Cytogenetic anchoring of radiation hybrid and virtual maps of sheep chromosome X and comparison of X chromosomes in sheep, cattle, and human.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A comprehensive physical map was generated for Ovis aries chromosome X (OARX) based on a cytogenomics approach. DNA probes were prepared from bacterial artificial chromosome (BAC) clones from the CHORI-243 sheep library and were assigned to G-banded metaphase spreads via fluorescence in-situ hybridization (FISH). A total of 22 BACs gave a single hybridization signal to the X chromosome and were assigned out of 32 tested. The positioned BACs contained 16 genes and a microsatellite marker which represent new cytogenetically mapped loci in the sheep genome. The gene and microsatellite loci serve to anchor between the exis...
Source: Chromosome Research - July 2, 2009 Category: Genetics & Stem Cells Authors: Goldammer T, Brunner RM, Rebl A, Wu CH, Nomura K, Hadfield T, Maddox JF, Cockett NE Tags: Chromosome Res Source Type: journals

Chromatin structure and DNA methylation of the IL-4 gene in human T(H)2 cells.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Human T(H)2 cell differentiation results in the selective demethylation of several specific CpG dinucleotides in the IL-4 and IL-13 genes, which are expressed in activated T(H)2, but not T(H)1, cells. This demethylation is accompanied by the appearance of six DNase I hypersensitive sites within 1.4 kb at the 5'-end of the IL-4 gene. Micrococcal nuclease (MNase) digestion revealed that in both T(H)1 and T(H)2 cells nine nucleosomes with a repeat length of 201 bp are identically positioned around the 5'-end of the IL-4 gene. However, only in T(H)2 cells are six out of the eight intervening linkers exposed to DNase I. Thi...
Source: Chromosome Research - June 11, 2009 Category: Genetics & Stem Cells Authors: Santangelo S, Cousins DJ, Triantaphyllopoulos K, Staynov DZ Tags: Chromosome Res Source Type: journals

Cruciform-forming inverted repeats appear to have mediated many of the microinversions that distinguish the human and chimpanzee genomes.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Submicroscopic inversions have contributed significantly to the genomic divergence between humans and chimpanzees over evolutionary time. Those microinversions which are flanked by segmental duplications (SDs) are presumed to have originated via non-allelic homologous recombination between SDs arranged in inverted orientation. However, the nature of the mechanisms underlying those inversions which are not flanked by SDs remains unclear. We have investigated 35 such inversions, ranging in size from 51-nt to 22056-nt, with the goal of characterizing the DNA sequences in the breakpoint-flanking regions. Using the macaque ...
Source: Chromosome Research - May 27, 2009 Category: Genetics & Stem Cells Authors: Kolb J, Chuzhanova NA, Högel J, Vasquez KM, Cooper DN, Bacolla A, Kehrer-Sawatzki H Tags: Chromosome Res Source Type: journals

The R2 mobile element of Rhynchosciara americana: Molecular, cytological and dynamic aspects.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Ribosomal RNA genes are encoded by large units clustered (18S, 5S, and 28S) in the nucleolar organizer region in several organisms. Sometimes additional insertions are present in the coding region for the 28S rDNA. These insertions are specific non-long terminal repeat retrotransposons that have very restricted integration targets within the genome. The retrotransposon present in the genome of Rhynchosciara americana, RaR2, was isolated by the screening of a genomic library. Sequence analysis showed the presence of conserved regions, such as a reverse transcriptase domain and a zinc finger motif in the amino terminal r...
Source: Chromosome Research - April 7, 2009 Category: Genetics & Stem Cells Authors: Rezende-Teixeira P, Siviero F, da Costa Rosa M, Machado-Santelli GM Tags: Chromosome Res Source Type: journals

Cross-species chromosome painting in Cetartiodactyla: Reconstructing the karyotype evolution in key phylogenetic lineages.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Recent molecular and morphological studies place Artiodactyla and Cetacea into the order Cetartiodactyla. Within the Cetartiodactyla such families as Bovidae, Cervidae, and Suidae are well studied by comparative chromosome painting, but many taxa that are crucial for understanding cetartiodactyl phylogeny remain poorly studied. Here we present the genome-wide comparative maps of five cetartiodactyl species obtained by chromosome painting with human and dromedary paint probes from four taxa: Cetacea, Hippopotamidae, Giraffidae, and Moschidae. This is the first molecular cytogenetic report on pilot whale, hippopotamus, o...
Source: Chromosome Research - April 7, 2009 Category: Genetics & Stem Cells Authors: Kulemzina AI, Trifonov VA, Perelman PL, Rubtsova NV, Volobuev V, Ferguson-Smith MA, Stanyon R, Yang F, Graphodatsky AS Tags: Chromosome Res Source Type: journals

The necessity of Darwin: This journal's tribute to the most influential scientist of all time.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Charles Darwin is considered by many to be one of the most influential scientists of all time. His theory of evolution via natural selection was astonishingly prescient in terms of what modern biology has revealed in the 150 years since the publication of The Origin of Species, especially since Darwin was unaware of even the most fundamental aspects of transmission genetics, not to mention molecular biology. Here we speculate what impact it would have had on Darwin's thinking if he had known what we now know about molecular biology and cytogenetics. PMID: 19343512 [PubMed - as supplied by publisher] (Source: Chromosome Research)
Source: Chromosome Research - April 3, 2009 Category: Genetics & Stem Cells Authors: Sessions SK, Macgregor HC Tags: Chromosome Res Source Type: journals

Chromosome mapping of H3 and H4 histone gene clusters in 35 species of acridid grasshoppers.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We analyse chromosome location of H3 and H4 histone gene clusters by fluorescence in-situ hybridization (FISH) in 35 species of Acrididae grasshoppers belonging to seven subfamilies. As in other organisms, H3 and H4 co-localized in the same chromosome region in the 11 species where double FISH was performed with the H3 and H4 DNA probes. Chromosome location of H3-H4 histone gene clusters showed high regularity in the species analysed, with all of them carrying a single H3-H4 cluster in an autosome which, in most cases, was located interstitially in the proximal chromosome third. In 17 out of the 21 species with 2nmale ...
Source: Chromosome Research - April 1, 2009 Category: Genetics & Stem Cells Authors: Cabrero J, López-León MD, Teruel M, Camacho JP Tags: Chromosome Res Source Type: journals

Influence of genetic background on tumor karyotypes: Evidence for breed-associated cytogenetic aberrations in canine appendicular osteosarcoma.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Recurrent chromosomal aberrations in solid tumors can reveal the genetic pathways involved in the evolution of a malignancy and in some cases predict biological behavior. However, the role of individual genetic backgrounds in shaping karyotypes of sporadic tumors is unknown. The genetic structure of purebred dog breeds, coupled with their susceptibility to spontaneous cancers, provides a robust model with which to address this question. We tested the hypothesis that there is an association between breed and the distribution of genomic copy number imbalances in naturally occurring canine tumors through assessment of a c...
Source: Chromosome Research - April 1, 2009 Category: Genetics & Stem Cells Authors: Thomas R, Wang HJ, Tsai PC, Langford CF, Fosmire SP, Jubala CM, Getzy DM, Cutter GR, Modiano JF, Breen M Tags: Chromosome Res Source Type: journals

Whole-arm reciprocal translocation in a hybrid population of Sorex araneus.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This study provides a description of an unambiguous case of a WART in S. araneus, a phenomenon that has recently been suggested to play a significant role in generating of chromosome races in this species. PMID: 19333767 [PubMed - as supplied by publisher] (Source: Chromosome Research)
Source: Chromosome Research - March 31, 2009 Category: Genetics & Stem Cells Authors: Fedyk S, Chętnicki W Tags: Chromosome Res Source Type: journals

Target chromosomes of inducible deletion by a Cre/inverted loxP system in mouse embryonic stem cells.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Chromosomal deletions are widely involved in serious genetic diseases and in the pathogenesis of cancers. These deletions often generate loss of heterozygosity (LOH) of one of the alleles of a tumor suppressor gene. Because of the technical difficulty inherent in genetic manipulation studies of a chromosome-wide deficiency, it has not been experimentally determined whether chromosome deletions could be a trigger for cancer development. Using the Cre/inverted loxP system, we have developed a chromosome elimination cassette (CEC) that Cre-dependently induces whole or partial deletions of the CEC-tagged chromosomes. Most ...
Source: Chromosome Research - March 31, 2009 Category: Genetics & Stem Cells Authors: Tada M, Matsumura H, Kurose Y, Nakatsuji N, Tada T Tags: Chromosome Res Source Type: journals