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https://www.readbyqxmd.com/read/28437173/the-karyotype-of-microsternarchus-aff-bilineatus-a-first-case-of-y-chromosome-degeneration-in-gymnotiformes
#1
Jéssica Almeida Batista, Adauto Lima Cardoso, Susana Suely Rodrigues Milhomem Paixão, Jonathan Stuart Ready, Julio Cesar Pieczarka, Cleusa Yoshiko Nagamachi
Various species and lineages that until recently were identified as Microsternarchus bilineatus (Hypopomidae, Gymnotiformes) have a widespread distribution in the Amazon and Orinoco river basins and across the Guiana shield. Recent molecular studies show five distinct lineages for Microsternarchus from different localities. These results suggest that this previously monotypic genus actually consists of more than one species. Here, we describe the karyotype of M. aff. bilineatus from the Cururutuia River (Bragança, Pará, Brazil)...
March 6, 2017: Zebrafish
https://www.readbyqxmd.com/read/28431265/nucleolar-reorganization-in-response-to-rdna-damage
#2
REVIEW
Marjolein van Sluis, Brian McStay
Nucleoli, sites of ribosome biogenesis, form around nucleolar organizer regions (NORs) comprising rDNA arrays, located on human acrocentric chromosome p-arms. NORs provide an opportunity to investigate the DNA double strand break (DSB) response at highly transcribed, repetitive, essential loci. Targeted introduction of DSBs into rDNA results in ATM-dependent inhibition of RNA-polymerase I transcription, coupled with movement of rDNA from the nucleolar interior to anchoring points at the periphery. Reorganization renders rDNA accessible to repair factors, normally excluded from nucleoli...
April 18, 2017: Current Opinion in Cell Biology
https://www.readbyqxmd.com/read/28423373/distribution-of-interstitial-telomeric-sequences-in-primates-and-the-pygmy-tree-shrew-scandentia
#3
Sofia Mazzoleni, Odessa Schillaci, Luca Sineo, Francesca Dumas
It has been hypothesized that interstitial telomeric sequences (ITSs), i.e., repeated telomeric DNA sequences found at intrachromosomal sites in many vertebrates, could be correlated to chromosomal rearrangements and plasticity. To test this hypothesis, we hybridized a telomeric PNA probe through FISH on representative species of 2 primate infraorders, Strepsirrhini (Lemur catta, Otolemur garnettii, Nycticebus coucang) and Catarrhini (Erythrocebus patas, Cercopithecus petaurista, Chlorocebus aethiops, Colobus guereza), as well as on 1 species of the order Scandentia, Tupaia minor, used as an outgroup for primates in phylogenetic reconstructions...
April 20, 2017: Cytogenetic and Genome Research
https://www.readbyqxmd.com/read/28402969/cytogenetic-characterization-of-brown-howler-monkeys-alouatta-guariba-clamitans-atelidae-platyrrhini-meiotic-confirmation-of-an-x1x1x2x2x3x3-x1x2x3y1y2-sex-chromosome-system
#4
Eliana R Steinberg, Vanessa B Fortes, Luis F Rossi, Laurete Murer, Maristela Lovato, Maria S Merani, Marta D Mudry
For brown howler monkeys (Alouatta guariba clamitans), diploid chromosome numbers varying from 2n = 45 to 2n = 52, with XX/XY, X1X1X2X2/X1X2Y, and X1X1X2X2X3X3/X1X2X3Y1Y2 sex chromosome systems have been described by mitotic studies but still await confirmation by meiotic analyses. We analyzed 3 male individuals sampled in the wild (in the municipality of Santa Maria, RS, Brazil) as well as 1 male and 1 female individual in captivity at the São Braz breeding center. Peripheral blood samples and testicular biopsies were taken...
April 13, 2017: Cytogenetic and Genome Research
https://www.readbyqxmd.com/read/28374190/a-genome-wide-study-of-hardy-weinberg-equilibrium-with-next-generation-sequence-data
#5
Jan Graffelman, Deepti Jain, Bruce Weir
Statistical tests for Hardy-Weinberg equilibrium have been an important tool for detecting genotyping errors in the past, and remain important in the quality control of next generation sequence data. In this paper, we analyze complete chromosomes of the 1000 genomes project by using exact test procedures for autosomal and X-chromosomal variants. We find that the rate of disequilibrium largely exceeds what might be expected by chance alone for all chromosomes. Observed disequilibrium is, in about 60% of the cases, due to heterozygote excess...
April 3, 2017: Human Genetics
https://www.readbyqxmd.com/read/28333343/centromere-destiny-in-dicentric-chromosomes-new-insights-from-the-evolution-of-human-chromosome-2-ancestral-centromeric-region
#6
Giorgia Chiatante, Giuliana Giannuzzi, Francesco Maria Calabrese, Evan E Eichler, Mario Ventura
Dicentric chromosomes are products of genomic rearrangements that place two centromeres on the same chromosome. Due to the presence of two primary constrictions, they are inherently unstable and overcome their instability by epigenetically inactivating and/or deleting one of the two centromeres, thus resulting in functionally monocentric chromosomes that segregate normally during cell division. Our understanding to date of dicentric chromosome formation, behavior and fate has been largely inferred from observational studies in plants and humans as well as artificially produced de novo dicentrics in yeast and in human cells...
March 15, 2017: Molecular Biology and Evolution
https://www.readbyqxmd.com/read/28251879/molecular-cytogenetic-analysis-reveals-the-existence-of-two-independent-neo-xy-sex-chromosome-systems-in-anatolian-pamphagidae-grasshoppers
#7
Ilyas Yerkinovich Jetybayev, Alexander Gennadievich Bugrov, Mustafa Ünal, Olesya Georgievna Buleu, Nikolay Borisovich Rubtsov
BACKGROUND: Neo-XY sex chromosome determination is a rare event in short horned grasshoppers, but it appears with unusual frequency in the Pamphagidae family. The neo-Y chromosomes found in several species appear to have undergone heterochromatinization and degradation, but this subject needs to be analyzed in other Pamphagidae species. We perform here karyotyping and molecular cytogenetic analyses in 12 Pamphagidae species from the center of biodiversity of this group in the previously-unstudied Anatolian plateau...
February 7, 2017: BMC Evolutionary Biology
https://www.readbyqxmd.com/read/28196983/genomic-profiling-of-acute-lymphoblastic-leukemia-in-ataxia-telangiectasia-patients-reveals-tight-link-between-atm-mutations-and-chromothripsis
#8
M Ratnaparkhe, M Hlevnjak, T Kolb, A Jauch, K K Maass, F Devens, A Rode, V Hovestadt, A Korshunov, A Pastorczak, W Mlynarski, S Sungalee, J Korbel, J Hoell, U Fischer, T Milde, C Kramm, M Nathrath, K Chrzanowska, E Tausch, M Takagi, T Taga, S Constantini, J Loeffen, J Meijerink, S Zielen, G Gohring, B Schlegelberger, E Maass, R Siebert, J Kunz, A E Kulozik, B Worst, D T Jones, S M Pfister, M Zapatka, P Lichter, A Ernst
Recent developments in sequencing technologies led to the discovery of a novel form of genomic instability, termed chromothripsis. This catastrophic genomic event, involved in tumorigenesis, is characterized by tens to hundreds of simultaneously acquired locally clustered rearrangements on one chromosome. We hypothesized that leukemias developing in individuals with Ataxia Telangiectasia, who are born with two mutated copies of the ATM gene, an essential guardian of genome stability, would show a higher prevalence of chromothripsis due to the associated defect in DNA double-strand break repair...
March 14, 2017: Leukemia: Official Journal of the Leukemia Society of America, Leukemia Research Fund, U.K
https://www.readbyqxmd.com/read/28177835/analysis-of-the-histone-cluster-in-senegalese-sole-solea-senegalensis-evidence-for-a-divergent-evolution-of-two-canonical-histone-clusters
#9
Manuel Alejandro Merlo, Roger Iziga, Silvia Portela-Bens, Ismael Cross, Nadezda Kosyakova, Thomas Liehr, Manuel Manchado, Laureana Rebordinos
The Senegalese sole (Solea senegalensis) is commercially very important and a priority species for aquaculture product diversification. The main histone cluster was identified within two BAC clones. However, two replacement histones (H1.0 and H3.3) were found in another BAC clone. Different types of canonical histones H2A and H2B were found within the same species for the first time. Phylogenetic analysis demonstrated that the different types of H1, H2A, and H2B histones were all more similar to each other than to canonical histones from other species...
December 10, 2016: Genome Génome / Conseil National de Recherches Canada
https://www.readbyqxmd.com/read/28111257/fragile-sites-dysfunctional-telomere-and-chromosome-fusions-what-is-5s-rdna-role
#10
Alain Victor Barros, Michele Andressa Vier Wolski, Viviane Nogaroto, Mara Cristina Almeida, Orlando Moreira-Filho, Marcelo Ricardo Vicari
Repetitive DNA regions are known as fragile chromosomal sites which present a high flexibility and low stability. Our focus was characterize fragile sites in 5S rDNA regions. The Ancistrus sp. species shows a diploid number of 50 and an indicative Robertsonian fusion at chromosomal pair 1. Two sequences of 5S rDNA were identified: 5S.1 rDNA and 5S.2 rDNA. The first sequence gathers the necessary structures to gene expression and shows a functional secondary structure prediction. Otherwise, the 5S.2 rDNA sequence does not contain the upstream sequences that are required to expression, furthermore its structure prediction reveals a nonfunctional ribosomal RNA...
April 15, 2017: Gene
https://www.readbyqxmd.com/read/28074622/-holostei-versus-halecostomi-problem-insight-from-cytogenetics-of-ancient-nonteleost-actinopterygian-fish-bowfin-amia-calva
#11
Zuzana Majtánová, Radka Symonová, Lenin Arias-Rodriguez, Lauren Sallan, Petr Ráb
Bowfin belongs to an ancient lineage of nonteleost ray-finned fishes (actinopterygians) and is the only extant survivor of a once diverged group, the Halecomorphi or Amiiformes. Owing to the scarcity of extant nonteleost ray-finned lineages, also referred as "living fossils," their phylogenetic interrelationships have been the target of multiple hypotheses concerning their sister group relationships. Molecular and morphological data sets have produced controversial results; bowfin is considered as either the sister group to genome-duplicated teleosts (together forming the group of Halecostomi) or to gars (Lepisosteiformes; together forming the group of Holostei)...
January 11, 2017: Journal of Experimental Zoology. Part B, Molecular and Developmental Evolution
https://www.readbyqxmd.com/read/27832130/detecting-mechanisms-of-karyotype-evolution-in-heterotaxis-orchidaceae
#12
Ana Paula Moraes, André Olmos Simões, Dario Isidro Ojeda Alayon, Fábio de Barros, Eliana Regina Forni-Martins
The karyotype is shaped by different chromosome rearrangements during species evolution. However, determining which rearrangements are responsible for karyotype changes is a challenging task and the combination of a robust phylogeny with refined karyotype characterization, GS measurements and bioinformatic modelling is necessary. Here, this approach was applied in Heterotaxis to determine what chromosome rearrangements were responsible for the dysploidy variation. We used two datasets (nrDNA and cpDNA, both under MP and BI) to infer the phylogenetic relationships among Heterotaxis species and the closely related genera Nitidobulbon and Ornithidium...
2016: PloS One
https://www.readbyqxmd.com/read/27830045/karyotype-diversity-of-pseudoscorpions-of-the-genus-chthonius-pseudoscorpiones-chthoniidae-in-the-alps
#13
Jana Kotrbová, Vera Opatova, Giulio Gardini, František Šťáhlavský
Pseudoscorpions are found in almost all terrestrial habitats. However, their uniform appearance presents a challenge for morphology-based taxonomy, which may underestimate the diversity of this order. We performed cytogenetic analyses on 11 pseudoscorpion species of the genus Chthonius C. L. Koch, 1843 from the Alps, including three subgenera: Chthonius (Chthonius) C. L. Koch, 1843, Chthonius (Ephippiochthonius) Beier, 1930 and Chthonius (Globochthonius) Beier, 1931 inhabiting this region. The results show that the male diploid number of chromosomes ranges from 21-35...
2016: Comparative Cytogenetics
https://www.readbyqxmd.com/read/27797956/a-portrait-of-ribosomal-dna-contacts-with-hi-c-reveals-5s-and-45s-rdna-anchoring-points-in-the-folded-human-genome
#14
Shoukai Yu, Bernardo Lemos
Ribosomal RNAs (rRNAs) account for >60% of all RNAs in eukaryotic cells and are encoded in the ribosomal DNA (rDNA) arrays. The rRNAs are produced from two sets of loci: the 5S rDNA array resides exclusively on human chromosome 1, whereas the 45S rDNA array resides on the short arm of five human acrocentric chromosomes. The 45S rDNA gives origin to the nucleolus, the nuclear organelle that is the site of ribosome biogenesis. Intriguingly, 5S and 45S rDNA arrays exhibit correlated copy number variation in lymphoblastoid cells (LCLs)...
December 31, 2016: Genome Biology and Evolution
https://www.readbyqxmd.com/read/27785415/recurrent-increased-nuchal-translucency-a-first-trimester-presentation-of-familial-13p-satellite-deletion
#15
I Uzun, R Has, E Alici, M Ozdemir, C Inan, S Erzincan
Chromosome 13 is one of the acrocentric chromosomes of the human karyotype. Acrocentric chromosomes are the most variable chromosomes in the human karyotype and these variations appear to have no clinical consequences. To the best of our knowledge, this is the first reported case of a first trimester presentation of a 13 short arm satellite deletion with markedly increased nuchal translucency (NT). In this case, the 13p short arm satellite deletion was associated with increased NT in two pregnancies from the same couple...
July 1, 2016: Balkan Journal of Medical Genetics: BJMG
https://www.readbyqxmd.com/read/27784020/classical-and-molecular-cytogenetics-of-the-panther-genet-genetta-maculata-mammalia-carnivora-viverridae
#16
Raquel Matoso Silva, Filomena Adega, Helena J Kjöllerström, Kim Labuschagne, Antoinette Kotze, Carlos Fernandes, Raquel Chaves, Maria do Mar Oom
Genets (Genetta) are a genus of African mammalian carnivorans with 14 currently recognized species, although taxonomic uncertainties remain, particularly regarding the number of species within the large-spotted genet complex. This study presents the first banded karyotype and molecular cytogenetic analysis of a genetically identified panther genet, Genetta maculata, the most common and widespread taxon of the large-spotted genet complex, with a wide distribution in sub-Saharan Africa. Sampled in Gauteng Province, South Africa, it could be assigned to the subspecies G...
2016: Cytogenetic and Genome Research
https://www.readbyqxmd.com/read/27710958/karyotype-and-mapping-of-repetitive-dnas-in-the-african-butterfly-fish-pantodon-buchholzi-the-sole-species-of-the-family-pantodontidae
#17
Petr Ráb, Cassia F Yano, Sébastien Lavoué, Oladele I Jegede, Luiz A C Bertollo, Tariq Ezaz, Zuzana Majtánová, Ezequiel A de Oliveira, Marcelo B Cioffi
The monophyletic order Osteoglossiformes represents one of the most ancestral groups of teleosts and has at least 1 representative in all continents of the southern hemisphere, with the exception of Antarctica. However, despite its phylogenetic and biogeographical importance, cytogenetic data in Osteoglossiformes are scarce. Here, karyotype and chromosomal characteristics of the lower Niger River population of the African butterfly fish Pantodon buchholzi, the sole species of the family Pantodontidae (Osteoglossiformes), were examined using conventional and molecular cytogenetic approaches...
2016: Cytogenetic and Genome Research
https://www.readbyqxmd.com/read/27698378/characterization-of-a-very-rare-case-of-living-ewe-buck-hybrid-using-classical-and-molecular-cytogenetics
#18
Alfredo Pauciullo, Christoph Knorr, Angela Perucatti, Alessandra Iannuzzi, Leopoldo Iannuzzi, Georg Erhardt
The natural occurrence of live hybrid offsprings between sheep and goats has been documented in literature, however all the studies have reported the mating of goats with rams, whereas the reciprocal cross was never documented. This study reports on a very rare case of interspecies hybridization occurred between a ewe (2n = 54, XX) and a buck (2n = 60, XY). The hybrid, born in a German flock under natural conditions, is characterised by an intermediate karyotype (2n = 57, XX). The CBA-banding has shown 3 metacentric and 54 acrocentric chromosomes, whereas the GTG- and RBA-banding have revealed that the autosomes involved in the hybrid combination were CHI1, 3; CHI2, 8 and CHI5, 11 corresponding to the metacentric chromosomes OAR1, OAR2 and OAR3...
October 4, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27676413/first-report-of-sex-chromosomes-in-achiridae-teleostei-pleuronectiformes-with-inferences-about-the-origin-of-the-multiple-x1x1x2x2-x1x2y-system-and-dispersal-of-ribosomal-genes-in-achirus-achirus
#19
Jamille A Bitencourt, Iracilda Sampaio, Robson T C Ramos, Marcelo Ricardo Vicari, Paulo Roberto A de M Affonso
American soles (family Achiridae) have been characterized by remarkable chromosomal variation even though several species lack basic cytogenetic information. This trend indicates that chromosomal traits can be useful to taxonomy once the morphological identification of some taxa in this family (e.g., Achirus species) is controversial. In this work, we expand the cytogenetic data in Achiridae by providing the first karyotypic analysis of Achirus achirus. An unusual multiple sex chromosome system (X1X1X2X2/X1X2Y) was detected, once males presented 2n = 33 with three unpaired chromosomes (X1X2Y) while females presented 2n = 34 with two acrocentric pairs (X1X1 and X2X2) found in hemizygosis in males...
February 2017: Zebrafish
https://www.readbyqxmd.com/read/27576706/the-relationship-between-human-nucleolar-organizer-regions-and-nucleoli-probed-by-3d-immunofish
#20
Marjolein van Sluis, Chelly van Vuuren, Brian McStay
3D-immunoFISH is a valuable technique to compare the localization of DNA sequences and proteins in cells where three-dimensional structure has been preserved. As nucleoli contain a multitude of protein factors dedicated to ribosome biogenesis and form around specific chromosomal loci, 3D-immunoFISH is a particularly relevant technique for their study. In human cells, nucleoli form around transcriptionally active ribosomal gene (rDNA) arrays termed nucleolar organizer regions (NORs) positioned on the p-arms of each of the acrocentric chromosomes...
2016: Methods in Molecular Biology
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