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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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
Anne-Marie Dutrillaux, Bernard Dutrillaux
The mitotic karyotypes of 17 species of African Goliathini (Cetoniinae) are described using various chromosome banding techniques. All but one are composed of 20 chromosomes, mostly metacentric, forming a karyotype assumed to be close to that of the Polyphaga ancestor. The most derived karyotypes are those of Goliathus goliatus Drury, 1770, with eight pairs of acrocentrics and Chlorocana africana Drury, 1773, with only14 chromosomes. In species of the genera Cyprolais Burmeister, 1842, Megalorhina Westwood, 1847, Stephanocrates Kolbe, 1894 and Stephanorrhina Burmeister, 1842, large additions of variable heterochromatin are observed on both some particular autosomes and the X chromosome...
2016: Comparative Cytogenetics
M Nirchio, C Oliveira, Z R Siccha-Ramirez, V F Sene, O R Sánchez-Romero, N R Ehemann, V Milana, A R Rossi, L Sola
Cytogenetic and molecular analyses enabled identification of two cytotypes among individuals of the spotted scorpion fish Scorpaena plumieri from Margarita Island, Venezuela. Cytotype 1 was characterized by 48 subtelo-acrocentric chromosomes and fundamental number (number of chromosome arms; FN) equalled 48, while cytotype 2 was characterized by two metacentric and 46 subtelo-acrocentric chromosomes and FN was 50. These cytotypes also differed in the location of the ribosomal gene clusters and in the distribution of the constitutive heterochromatin...
October 2016: Journal of Fish Biology
Mohammad Miryounesi, Mehdi Diantpour, Elahe Motevaseli, Soudeh Ghafouri-Fard
BACKGROUND: Robertsonian translocations are structural chromosomal abnormalities caused by fusion of two acrocentric chromosomes. In carriers of such translocations, different modes of segregations would result in the formation of either balanced (alternate segregation mode) or unbalanced (adjacent 1, adjacent 2, and 3:1 segregation modes) gametes. In addition, there is an increased risk for imprinting disorders in their offspring. Although it has been estimated that 1/1000 healthy persons carry a Robertsonian translocation, homozygosity for this type of structural chromosomal abnormality has been reported rarely...
July 2016: Journal of Reproduction & Infertility
Luana Pereira Dos Santos, Carine Mendonça Francisco, Jonathan Pena Castro, Patrícia Barbosa, Sandra Morelli, Luiz Antonio de Oliveira, Roberto Ferreira Artoni
Accessing the taxonomy of fish is a basic condition for the conservation of species, and the understanding of their evolutionary relationships. Many Neotropical species of fishes of the order Characiformes are considered incertae sedis because of a lack of consistent evidence of monophyly, with the genus Astyanax among them. With a cytotaxonomic and evolutionary purpose, we compared the karyotype of two species of Astyanax: Astyanax paranae and Astyanax elachylepis. Conventional cytogenetic analyses revealed 2n = 50 chromosomes for the two species, with interspecific and interpopulation karyotype variations...
December 2016: Zebrafish
Isac Silva de Jesus, Milena Ferreira, Caroline Garcia, Leila Braga Ribeiro, José Antônio Alves-Gomes, Eliana Feldberg
Microsternarchus bilineatus is a neotropical electric fish species widely distributed in Amazonian ecosystems. This work reports the first karyotypic description of the species M. bilineatus, which presented 2n = 48 chromosomes, with a distinct karyotypic formula between the sexes: males with 21 metacentric (m)/submetacentric (sm) + 27 subtelocentric (st)/acrocentric (a) and fundamental number (FN) = 69 and females with 20 m/sm + 28 st/a and FN = 68. We found a probable recent sex system of XX/XY type...
December 2016: Zebrafish
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