Consulta: subjectFacets:"Chromosome evolution"
Registros recuperados: 16
Data/hora: 09/06/2024 17:33:29

Chromosomal diversification of diploid number, heterochromatin and rDNAs in two species of Phanaeus beetles (Scarabaeidae, Scarabaeinae)
Provedor de dados: Genetics and Molecular Biology
Autores: Arcanjo,Amanda; Cabral-de-Mello,Diogo Cavalcanti; Martins,Cesar; Moura,Rita de Cássia de; Souza,Maria José de.
The genus Phanaeus is included in the tribe Phanaeini, one of the most diverse tribes within the subfamily Scarabaeinae in terms of chromosomal characteristics. However, so far the species of this genus were not studied with differential cytogenetic techniques, limiting any inference of the probable mechanisms responsible for this diversity. In this work, several techniques were applied with the aim of cytogenetically characterizing two Phanaeus species. The karyotype found for Phanaeus (Notiophanaeus) chalcomelas was 2n = 12, neo-XY, and that of P. (N.) splendidulus was 2n = 20, Xy p, considered primitive for the family Scarabaeidae. The chromosomes of both species showed a high amount of constitutive heterochromatin (CH), with blocks rich in base pairs...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Karyotype; Chromosome evolution; Repetitive DNA; FISH.
Ano: 2013
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572013000300007

Chromosome evolution in tiger beetles: Karyotypes and localization of 18S rDNA loci in Neotropical Megacephalini (Coleoptera, Cicindelidae)
Provedor de dados: Genetics and Molecular Biology
Autores: Proença,Sónia J.R.; Collares-Pereira,Maria João; Serrano,Artur R.M.
Four Neotropical tiger beetle species, three from the genus Megacephala and one from the genus Oxycheila, currently assigned to the tribe Megacephalini were examined cytogenetically. All three Megacephala species showed simple sex chromosome systems of the X0/XX type but different numbers of autosomal pairs (15 in M. cruciata, 14 in M. sobrina and 12 in M. rutilans), while Oxycheila tristis was inferred to have a multiple sex chromosome system with four X chromosomes (2n = 24 + X1X2X3X4Y/X1X1X2X2X3X3X4X4). Fluorescence in situ hybridization (FISH) using a PCR-amplified 18S rDNA fragment as a probe revealed the presence of rDNA clusters located exclusively on the autosomes in all the Megacephala species (five clusters in M. cruciata, eight in M. sobrina and...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Chromosome evolution; Cicindelidae; Megacephalini; Oxycheila; RDNA localization; Sex chromosome system.
Ano: 2005
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572005000500012

American marsupials chromosomes: why study them?
Provedor de dados: Genetics and Molecular Biology
Autores: Svartman,Marta.
Marsupials, one of the three main groups of mammals, are only found in Australia and in the American continent. Studies performed in Australian marsupials have demonstrated the great potential provided by the group for the understanding of basic genetic mechanisms and chromosome evolution in mammals. Genetic studies in American marsupials are relatively scarce and cytogenetic data of most species are restricted to karyotype descriptions, usually without banding patterns. Nevertheless, the first marsupial genome sequenced was that of Monodelphis domestica, a South American species. The knowledge about mammalian genome evolution and function that resulted from studies on M. domestica is in sharp contrast with the lack of genetic data on most American...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Marsupials; Cytogenetics; Chromosome evolution.
Ano: 2009
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572009000400002

Identifying Mazama gouazoubira (Artiodactyla; Cervidae) chromosomes involved in rearrangements induced by doxorubicin
Provedor de dados: Genetics and Molecular Biology
Autores: Tomazella,Iara Maluf; Abril,Vanessa Veltrini; Duarte,José Maurício Barbanti.
Abstract The process of karyotype evolution in Cervidae from a common ancestor (2n = 70, FN = 70) has been marked by complex chromosomal rearrangements. This ancestral karyotype has been retained by the current species Mazama gouazoubira (Fischer 1814), for which a chromosomal polymorphism (Robertsonian translocations and the presence of B chromosomes) has been described, presumably caused by a chromosome fragility. Thus, this study has identified doxorubicin-induced chromosome aberrations and mapped the regions involved in breaks, which may be related to the chromosome evolution process. G-banding pattern showed that 21 pairs of chromosomes presented chromosomal aberrations, 60% of the total chromosome number of the species M. gouazoubira. Among...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Chromosomal aberrations; Chromosome evolution; Brown brocket deer; G-banding.
Ano: 2017
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572017000300460

Cytogenetic analysis of three sea catfish species (Teleostei, Siluriformes, Ariidae) with the first report of Ag-NOR in this fish family
Provedor de dados: Genetics and Molecular Biology
Autores: Nirchio,Mauro; Martinez,Emanuel Ricardo Monteiro; Foresti,Fausto; Oliveira,Claudio.
Despite their ecological and economical importance, fishes of the family Ariidae are still genetically and cytogenetically poorly studied. Among the 133 known species of ariids, only eight have been karyotyped. Cytogenetic analyses performed on Genidens barbus and Sciades herzbergii revealed that both species have 2n = 56 chromosomes and Cathorops aff. mapale has 2n = 52 chromosomes: Genidens barbus has 10 Metacentrics (M), 14 Submetacentrics (SM), 26 Subtelocentrics (ST), and 6 Acrocentrics (A), Sciades herzbergii has 14M, 20SM, 18ST and 4A, whereas Cathorops aff. mapale has 14M, 20SM, and 18ST. The nucleolus organizer regions (NORs) were found in a single chromosome pair on the short arm of a large-sized ST pair in Genidens barbus and on the short arm of...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Cytogenetics; Ag-NORs; Chromosome evolution; Chromosome rearrangements; Fish.
Ano: 2010
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572010000200011

Cytogenetic variability in three species of the genus Cicindela (s.l.) (Coleoptera, Cicindelidae): karyotypes and localization of 18S rDNA genes
Provedor de dados: Genetics and Molecular Biology
Autores: Proença,Sónia J. R.; Collares-Pereira,Maria João; Serrano,Artur R. M.
Three tiger beetle species from the Cicindelini tribe were examined cytogenetically and found to have the following karyotypes: Cicindela argentata, 2n = 18 + X1X2Y/X1X1X2X 2; Cicindela aurulenta, 2n=18 + X1X2X3Y/X1X1X 2X2X3X3 and Cicindela suturalis, 2n = 18 + X1X2X3X4Y/X1X 1X2X2X3X3X4X 4. Fluorescence in situ hybridization (FISH) using a PCR-amplified 18S rDNA fragment as a probe showed the presence of ribosomal clusters in two autosomes in C. argentata, two autosomes and two heterosomes in C. aurulenta and in two heterosomes in C. suturalis (male configuration), revealing two new patterns of rDNA localization. Such results are representative of the cytogenetic variability observed in the species rich genus Cicindela (sensu lato) mainly as regards the...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Chromosome evolution; Cicindela; Multiple sex chromosomes; RDNA localization; Tiger beetles.
Ano: 2004
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572004000400015

Characterization and chromosomal mapping of the DgmarMITE transposon in populations of Dichotomius (Luederwaldtinia) sericeus species complex (Coleoptera: Scarabaeidae)
Provedor de dados: Genetics and Molecular Biology
Autores: Amorim,Igor Costa; Costa,Rafaelle Grazielle Coelho; Xavier,Crislaine; Moura,Rita de Cássia de.
Abstract Transposable elements are dispersed repetitive DNA sequences that can move within the genome and are related to genome and chromosome evolution, adaptation, and speciation. The aim of this study was to characterize and determine the chromosomal location and accumulation of a Mariner-like element in populations of four phylogenetically related species of the Dichotomius (Luederwaldtinia) sericeus complex. Mapping of the isolated element was performed by fluorescent in situ hybridization in different populations of analyzed species. Characterization of the isolated element revealed a degenerated transposon, named DgmarMITE. This transposon is 496-bp-long, AT rich (57%), and contains 24 bp terminal inverted repeats. In situ mapping revealed presence...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Mariner-like elements; Cross-mobilization; Chromosome evolution.
Ano: 2018
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572018000300419

Agmatoploidy and symploidy: a critical review
Provedor de dados: Genetics and Molecular Biology
Autores: Guerra,Marcelo.
Abstract Agmatoploidy is a type of chromosome rearrangement that involves the fragmentation of an entire chromosome complement, generating a diploid with double its original chromosome number. Agmatoploidy and other related karyotype changes, such as symploidy (the opposite change, promoted by chromosome fusion), partial agmatoploidy, polyagmatoploidy, etc., are restricted to species with holokinetic chromosomes and are assumed to play an important role in their karyotype evolution. However, a critical review of the literature shows that examples of chromosome number doubling by agmatoploidy are rare and not clearly demonstrated, while partial agmatoploidy and partial symploidy seem to be the same as ascending and descending disploidy, respectively. It is...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Agmatoploidy; Symploidy; Holocentrics; Holokinetic chromosomes; Chromosome evolution.
Ano: 2016
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572016000400492

The distribution of 45S rDNA sites in bird chromosomes suggests multiple evolutionary histories
Provedor de dados: Genetics and Molecular Biology
Autores: Degrandi,Tiago Marafiga; Gunski,Ricardo José; Garnero,Analía del Valle; Oliveira,Edivaldo Herculano Correa de; Kretschmer,Rafael; Souza,Marcelo Santos de; Barcellos,Suziane Alves; Hass,Iris.
Abstract The distribution of 45S rDNA cluster in avian karyotypes varies in different aspects, such as position, number of bearer chromosomes, and bearers being macro- or microchromosomes. The present study investigated the patterns of variation in the 45S rDNA-bearer chromosomes of birds in order to understand the evolutionary dynamics of the cluster configuration and its contribution to the evolution of bird karyotypes. A total of 73 bird species were analyzed, including both published data and species for which rDNA-FISH was conducted for the first time. In most birds, the 45S rDNA clusters were located in a single pair of microchromosomes. Hence, the location of 45S rDNA in macrochromosomes, observed only in Neognathae species, seems to be a derived...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: FISH; Chromosome; Chromosome evolution; Cytogenetics; Aves.
Ano: 2020
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572020000400601

Karyological characterization of four Neotropical fish species of the genus Hisonotus (Teleostei, Loricariidae, Hypoptopomatinae) from distinct Brazilian river basins
Provedor de dados: Genetics and Molecular Biology
Autores: Andreata,Artur Antonio; Oliveira,Claudio; Foresti,Fausto.
The karyotypes of four Hisonotus species (two provisionally-named species A and D, H. nigricauda, and H. leucofrenatus) were found to have the same diploid number of 2n = 54 and interstitial silver-staining nucleolus organizer regions (Ag-NORs) located on the long arm of the largest metacentric pair. The C-banding pattern appeared to be species-specific, with one group (H. nigricauda and the unnamed species A and D) being characterized by small amounts of positive C-banded segments and containing a sub-group (species A and D) identified by a large positive C-banded segment on a small metacentric chromosome pair. The second group contained different samples of H. leucofrenatus, characterized by a larger amount of C-band positive segments spread over several...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Fish cytogenetics; Karyotypes; Ag-NORs; C-band; Chromosome evolution.
Ano: 2006
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572006000100013

Cytogenetic analysis in western Atlantic snappers (Perciformes, Lutjanidae)
Provedor de dados: Genetics and Molecular Biology
Autores: Rocha,Érika Cruz; Molina,Wagner Franco.
The Lutjanidae or snappers are a family of perciform fishes, mainly marine but with some members living in estuaries and entering fresh water to feed. Some are important food fish. Cytogenetic data for Lutjanidae are scarce. In the present work, we cytogenetically characterized through conventional Giemsa staining techniques, Ag-NOR and C-banding the species Ocyurus chrysurus, Lutjanus analis, L. alexandrei, L. cyanopterus, L. jocu and L. synagris, all found along the Brazilian coast. Karyotype analysis of all six species showed a modal value of 2n = 48 acrocentric chromosomes. Single NORs were found at pericentromeric position on the long arms of the 2nd pair in O. chrysurus, L. alexandrei and L. cyanopterus, on the 5th pair in L. analis and on the 23rd...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Chromosome evolution; Fish cytogenetics; Lutjanidae; Lutjanus; Ocyurus.
Ano: 2008
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572008000300011

Karyotype description of five species of Trichomycterus (Teleostei: Siluriformes: Trichomycteridae)
Provedor de dados: Genetics and Molecular Biology
Autores: Sato,Luciana Ramos; Oliveira,Claudio; Foresti,Fausto.
Trichomycteridae is a family of small catfish which are widely distributed throughout Southern Central America and South America. The present study showed that the cis-Andean species Trichomycterus florensis, Trichomycterus sp. aff. Trichomycterus itatiyae, Trichomycterus reinhardti, Trichomycterus davisi and Trichomycterus auroguttatus had 2n = 54 chromosomes (42 metacentric, 10 submetacentric and 2 subtelocentric), with T. reinhardti, T. auroguttatus and T. sp. aff. T. itatiyae exhibiting only one chromosome pair with silver-stained nucleolus organizer regions (NORs). The cytogenetic data suggest the existence of at least two groups of species in the cis-Andean representatives of the genus Trichomycterus. In the first group the first metacentric pair is...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Chromosome evolution; NOR banding; Fish.
Ano: 2004
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572004000100008

Molecular phylogenies, chromosomes and dispersion in Brazilian akodontines (Rodentia, Sigmodontinae)
Provedor de dados: Iheringia Série Zoologia
Autores: Barros,Maria Claudene; Sampaio,Iracilda; Schneider,Horacio; Langguth,Alfredo.
A new molecular phylogeny for akodontine rodents from Brazil was proposed. The phylogenetic tree was enriched with the area of occurrence and with information on the karyotype of the samples. Based on this enriched tree, and with a described methodology, hypotheses were proposed on the karyotype and area of occurrence of the ancestors of each Clade. Thus it was possible to discuss hypotheses on chromosome evolution of the group, and on dispersion events from the "area of original differentiation" of akodontines in the Andes. Chromosome evolution started with high diploid numbers (2n=52) and showed a tendency to reduction (until 2n=14 in more recent clades). Independent side-branches of the tree showed 2n reduction and in one case the 2n increased. At least...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Brazilian akodontines; Chromosome evolution; Biogeography; Molecular phylogeny.
Ano: 2009
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0073-47212009000400006

Cytotaxonomic diagnosis of Trichomycterus diabolus (Teleostei: Trichomycteridae) with comments about its evolutionary relationships with co-generic species
Provedor de dados: Neotropical Ichthyology
Autores: Torres,Rodrigo A.; Oliveira,Claudio; Foresti,Fausto.
The karyotype and the Ag-NOR location of a sample of Trichomycterus diabolus collected in the córrego Hortelã (Botucatu, São Paulo, Brazil) are described. The species exhibited 2n=56 chromosomes (42 metacentrics, 12 submetacentrics and 2 subtelocentrics) and the nucleolus organizing region located near to the centromere on the long arm of the largest metacentric pair. The presence of 2n=56 chromosomes in T. diabolus is an interesting characteristic since until now all cis-Andean species karyotyped presented 2n=54 chromosomes while almost all trans-Andean species presented different diploid numbers. The possible origin of this unexpected karyotypic form is discussed.
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Trichomycterinae; Karyotype; Chromosome evolution; Fish cytogenetic.
Ano: 2004
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252004000300003

Preferential accumulation of sex and Bs chromosomes in biarmed karyotypes by meiotic drive and rates of chromosomal changes in fishes
Provedor de dados: Anais da Academia Brasileira de Ciências
Autores: MOLINA,WAGNER F.; MARTINEZ,PABLO A.; BERTOLLO,LUIZ A.C.; BIDAU,CLAUDIO J.
Mechanisms of accumulation based on typical centromeric drive or of chromosomes carrying pericentric inversions are adjusted to the general karyotype differentiation in the principal Actinopterygii orders. Here, we show that meiotic drive in fish is also supported by preferential establishment of sex chromosome systems and B chromosomes in orders with predominantly bi-brachial chromosomes. The mosaic of trends acting at an infra-familiar level in fish could be explained as the interaction of the directional process of meiotic drive as background, modulated on a smaller scale by adaptive factors or specific karyotypic properties of each group, as proposed for the orthoselection model.
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Actinopterygii; B chromosomes; Centromeric drive; Chromosome evolution; Sex chromosomes.
Ano: 2014
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652014000401801

Cytogenetics and biogeography: considerations about the natural origin of Hoplias malabaricus (Characiformes, Erythrinidae) on the Iguaçu river
Provedor de dados: Brazilian Archives of Biology and Technology
Autores: Vicari,Marcelo Ricardo; Pazza,Rubens; Artoni,Roberto Ferreira; Margarido,Vladimir Pavan; Bertollo,Luiz Antonio Carlos.
Hoplias malabaricus (trahyra) is a widespread fish species over the Neotropical region with diversified inter-populational karyotypes (cytotypes), which may correspond to a species complex. Despite the wide distribution in the South American basins, some authors have questioned its natural origin in the Iguaçu river, an important Brazilian river basin which is characterized by several endemic fish species. We have analyzed the karyotype of H. malabaricus from different collection sites of this river, by conventional and banding methods. Our results, in addition to our previous data concerning geographic distribution of the cytotypes, contribute to better understand the origin of H. malabaricus on the Iguaçu river, reinforcing the proposition that it is a...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Chromosome evolution; Karyotypes distribution; Endemism.
Ano: 2006
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132006000300015