Academic literature on the topic 'Karyotype differentiation'
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Journal articles on the topic "Karyotype differentiation"
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Coulaud, Joëlle, Nasrine Barghi, Claude Lefèbvre, and Sonja Siljak-Yakovlev. "Cytogenetic variation in populations of Armeria maritima (Mill.) Willd. in relation to geographical distribution and soil stress tolerances." Canadian Journal of Botany 77, no. 5 (1999): 673–85. http://dx.doi.org/10.1139/b99-028.
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Ten Armeria maritima (Mill.) Willd. populations (2n = 18) from contrasting ecogeographic situations were compared using 30 morphometric characters of karyotype and frequencies of abnormal metaphase and interphase cells in root-tip meristems. Despite the general symmetry and similarities, karyotypes of populations can be distinguished using a set of precise karyotypic features. Variations within populations mainly concerned the occurrence of satellites and weakly condensed areas of chromosomes. Total chromosome length measurements were congruent with flow cytometry estimates of DNA amounts. The geographical differentiation of European population karyotypes is in accordance with previously defined biochemical clustering. One population from Germany (ssp. bottendorfensis) is more similar to the American population (ssp. californica) than to the other European populations. Proposed trends of karyotype evolution are discussed in comparison with previous results on other character sets and taxonomic treatments. The species karyotype seems particularly unstable, as chromosome strong links at mitosis cause breaks generating chromosomal mutations and aneuploidy at the intra-individual level in all the populations. Abnormal interphase cells were found in most of the populations but were especially frequent in heavy-metal tolerant populations. The highest frequencies of karyotype aberrations were found in the American population and in populations adapted to soils with high levels of heavy metals or salinity. The frequency of interphase aberrations appeared to be related to the mean level of heavy-metal tolerance of populations. Consequently, the two types of abnormalities may originate from independent mechanisms. The genome behaviour of A. maritima is discussed with reference to recent findings concerning the effects of soil toxicity on plant genomes.Key words: Armeria maritima, karyotype, population differentiation, soil stress tolerance, mitotic aberrations, abnormal nuclei.
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Mariotto, Sandra, Liano Centofante, Marcelo Vicari, Roberto Artoni, and Filho Orlando Moreira. "Chromosomal diversification in ribosomal DNA sites in Ancistrus Kner, 1854 (Loricariidae, Ancistrini) from three hydrographic basins of Mato Grosso, Brazil." Comparative Cytogenetics 5, no. (4) (2011): 289–300. https://doi.org/10.3897/compcytogen.v5i4.1757.
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Populations of seven <i>Ancistrus </i>species were analyzed from streams and rivers of three hydrographic Brazilian basins. All populations showed different diploid numbers (2n), fundamental numbers (FNs), and karyotypes. Some representatives of Loricariidae have 2n = 54 chromosomes, which is very likely an ancestral cytotaxonomic characteristic, but many other representatives show extensive karyotype diversification. In the <i>Ancistrus</i> species studied, extensive karyotypic differentiation, which is generally associated with chromosome number reduction and rearrangement of the ribosomal RNA gene (rDNA) sites, was verified. Chromosomal locations of 18S and 5S rDNA were jointly detected using fluorescence <i>in situ</i> hybridization (FISH). In all the <i>Ancistrus </i>species analyzed, 18S rDNA sites were detected only on one chromosome pair, though this differed among species. 5S rDNA was located on 1–3 chromosome pairs either separately or in synteny with 18S rDNA in four of the seven species/populations. Hence the karyotype differentiation in <i>Ancistrus</i> species could be associated with a morphological speciation process, suggesting that chromosome fusions, inversions, deletions, duplications, and heterochromatination could contribute to the karyotype evolution of these neotropical armored catfishes.
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Pucci, Marcela Baer, Viviane Nogaroto, Luiz Antonio Carlos Bertollo, Orlando Moreira-Filho, and Marcelo Ricardo Vicari. "The karyotypes and evolution of ZZ/ZW sex chromosomes in the genus Characidium (Characiformes, Crenuchidae)." Comparative Cytogenetics 12, no. (3) (2018): 421–38. https://doi.org/10.3897/CompCytogen.v12i3.28736.
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Available data on cytotaxonomy of the genus Characidium Reinhardt, 1867, which contains the greatest number of species in the Characidiinae (Crenuchidae), with 64 species widely distributed throughout the Neotropical region, were summarized and reviewed. Most Characidium species have uniform diploid chromosome number (2n) = 50 and karyotype with 32 metacentric (m) and 18 submetacentric (sm) chromosomes. The maintenance of the 2n and karyotypic formula in Characidium implies that their genomes did not experience large chromosomal rearrangements during species diversification. In contrast, the internal chromosomal organization shows a dynamic differentiation among their genomes. Available data indicated the role of repeated DNA sequences in the chromosomal constitution of the Characidium species, particularly, in sex chromosome differentiation. Karyotypes of the most Characidium species exhibit a heteromorphic ZZ/ZW sex chromosome system. The W chromosome is characterized by high rates of repetitive DNA accumulation, including satellite, microsatellite, and transposable elements (TEs), with a varied degree of diversification among species. In the current review, the main Characidium cytogenetic data are presented, highlighting the major features of its karyotype and sex chromosome evolution. Despite the conserved karyotypic macrostructure with prevalent 2n = 50 chromosomes in Characidium, herein we grouped the main cytogenetic information which led to chromosomal diversification in this Neotropical fish group.
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STIEFKENS, L., and G. BERNARDELLO. "KARYOTYPE STUDIES IN LYCIUM SECTIONS SCHISTOCALYX AND SCLEROCARPELLUM (SOLANACEAE)." Edinburgh Journal of Botany 62, no. 1-2 (2005): 53–67. http://dx.doi.org/10.1017/s0960428606000023.
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Mitotic chromosome numbers and karyotypes of species in two sections of Lycium (Solanaceae) from the American continent were determined in 23 populations. Both species in the small South American section Schistocalyx were examined: Lycium ciliatum and three varieties of L. chilense had diploid (2n=24) as well as tetraploid (2n=48) populations. Lycium ameghinoi from the small American section Sclerocarpellum was diploid with 2n=24. The basic number x=12 for the genus was confirmed. The karyotypes of these taxa were highly symmetrical: the chromosomes were metacentric or submetacentric with the formula: 11 m + 1 sm. Microsatellites were present in chromosome pair no. 1 and were attached to the short arms. As in other Lycium taxa already investigated, karyotypic features suggest that morphological differentiation in the group has not been accompanied by karyotype divergence.
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Pucci, Marcela Baer, Viviane Nogaroto, Luiz Antonio Carlos Bertollo, Orlando Moreira-Filho, and Marcelo Ricardo Vicari. "The karyotypes and evolution of ZZ/ZW sex chromosomes in the genus Characidium (Characiformes, Crenuchidae)." Comparative Cytogenetics 12, no. 3 (2018): 421–38. http://dx.doi.org/10.3897/compcytogen.v12i3.28736.
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Available data on cytotaxonomy of the genus Characidium Reinhardt, 1867, which contains the greatest number of species in the Characidiinae (Crenuchidae), with 64 species widely distributed throughout the Neotropical region, were summarized and reviewed. Most Characidium species have uniform diploid chromosome number (2n) = 50 and karyotype with 32 metacentric (m) and 18 submetacentric (sm) chromosomes. The maintenance of the 2n and karyotypic formula in Characidium implies that their genomes did not experience large chromosomal rearrangements during species diversification. In contrast, the internal chromosomal organization shows a dynamic differentiation among their genomes. Available data indicated the role of repeated DNA sequences in the chromosomal constitution of the Characidium species, particularly, in sex chromosome differentiation. Karyotypes of the most Characidium species exhibit a heteromorphic ZZ/ZW sex chromosome system. The W chromosome is characterized by high rates of repetitive DNA accumulation, including satellite, microsatellite, and transposable elements (TEs), with a varied degree of diversification among species. In the current review, the main Characidium cytogenetic data are presented, highlighting the major features of its karyotype and sex chromosome evolution. Despite the conserved karyotypic macrostructure with prevalent 2n = 50 chromosomes in Characidium, herein we grouped the main cytogenetic information which led to chromosomal diversification in this Neotropical fish group.
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Sotero-Caio, C.G., J.C. Pieczarka, C.Y. Nagamachi, et al. "Chromosomal Homologies among Vampire Bats Revealed by Chromosome Painting (Phyllostomidae, Chiroptera)." Cytogenetic and Genome Research 132, no. 3 (2011): 156–64. https://doi.org/10.5281/zenodo.13429619.
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(Uploaded by Plazi for the Bat Literature Project) Substantial effort has been made to elucidate karyotypic evolution of phyllostomid bats, mostly through comparisons of G-banding patterns. However, due to the limited number of G-bands in respective karyotypes and to the similarity of non-homologous bands, an accurate evolutionary history of chromosome segments remains questionable. This is the case for vampire bats (Desmodontinae). Despite several proposed homologies, banding data have not yet provided a detailed understanding of the chromosomal changes within vampire genera. We examined karyotype differentiation of the 3 species within this subfamily using whole chromosomal probes from <i>Phyllostomus hastatus </i>(Phyllostominae) and <i>Carollia brevicauda </i>(Carolliinae). Painting probes of <i>P. hastatus </i>respectively detected 22, 21 and 23 conserved segments in <i>Diphylla ecaudata</i>,<i> Diaemus youngi</i>, and <i>Desmodus rotundus</i> karyotypes, whereas 27, 27 and 28 were respectively detectedwith <i>C. brevicauda </i>paints. Based on the evolutionary relationships proposed by morphological and molecular data, we present probable chromosomal synapomorphies for vampire bats and propose chromosomes that were present in the common ancestor of the 5 genera analyzed. Karyotype comparisons allowed us to relate a number of conserved chromosomal segments among the 5 species, providing a broader database for understanding karyotype evolution in the family.
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Sotero-Caio, C.G., J.C. Pieczarka, C.Y. Nagamachi, et al. "Chromosomal Homologies among Vampire Bats Revealed by Chromosome Painting (Phyllostomidae, Chiroptera)." Cytogenetic and Genome Research 132, no. 3 (2011): 156–64. https://doi.org/10.5281/zenodo.13429619.
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(Uploaded by Plazi for the Bat Literature Project) Substantial effort has been made to elucidate karyotypic evolution of phyllostomid bats, mostly through comparisons of G-banding patterns. However, due to the limited number of G-bands in respective karyotypes and to the similarity of non-homologous bands, an accurate evolutionary history of chromosome segments remains questionable. This is the case for vampire bats (Desmodontinae). Despite several proposed homologies, banding data have not yet provided a detailed understanding of the chromosomal changes within vampire genera. We examined karyotype differentiation of the 3 species within this subfamily using whole chromosomal probes from <i>Phyllostomus hastatus </i>(Phyllostominae) and <i>Carollia brevicauda </i>(Carolliinae). Painting probes of <i>P. hastatus </i>respectively detected 22, 21 and 23 conserved segments in <i>Diphylla ecaudata</i>,<i> Diaemus youngi</i>, and <i>Desmodus rotundus</i> karyotypes, whereas 27, 27 and 28 were respectively detectedwith <i>C. brevicauda </i>paints. Based on the evolutionary relationships proposed by morphological and molecular data, we present probable chromosomal synapomorphies for vampire bats and propose chromosomes that were present in the common ancestor of the 5 genera analyzed. Karyotype comparisons allowed us to relate a number of conserved chromosomal segments among the 5 species, providing a broader database for understanding karyotype evolution in the family.
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Krysanov, Eugene, and Tatiana Demidova. "Extensive karyotype variability of African fish genus Nothobranchius (Cyprinodontiformes)." Comparative Cytogenetics 12, no. (3) (2018): 387–402. https://doi.org/10.3897/CompCytogen.v12i3.25092.
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Karyotypes of 65 species of the genus Nothobranchius Peters, 1868 were reviewed and of those 35 examined first time. The results of present study have shown that fishes of the genus Nothobranchius possessed highly diverse karyotypes. The diploid chromosome number (2n) ranged from 16 to 50. The most frequent 2n was 2n = 36 (in 35 species) while the second one 2n = 38 (in 13 species). Proportion of biarmed chromosomes varied from 0 to 95% between species. Diploid chromosome number variability apparently exists as a result of chromosomal fusions or fissions and extensive karyotypic formula alterations promoting by inversions. Multiple sex chromosomes of system X<sub>1</sub>X<sub>1</sub>X<sub>2</sub>X<sub>2</sub>/X<sub>1</sub>X<sub>2</sub>Y type were found only in karyotypes of 5 species. The extensive karyotype variability, unusual for teleosts, of genus Nothobranchius can be likely associated with the characteristics of its life cycle and inhabiting under unstable environment of East African savannah temporal pools.
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Krysanov, Eugene Yu, Béla Nagy, Brian R. Watters, Alexandr Sember, and Sergey A. Simanovsky. "Karyotype differentiation in the Nothobranchius ugandensis species group (Teleostei, Cyprinodontiformes), seasonal fishes from the east African inland plateau, in the context of phylogeny and biogeography." Comparative Cytogenetics 17, no. 1 (2023): 13–29. http://dx.doi.org/10.3897/compcytogen.v7.i1.97165.
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The karyotype differentiation of the twelve known members of the Nothobranchius ugandensis Wildekamp, 1994 species group is reviewed and the karyotype composition of seven of its species is described herein for the first time using a conventional cytogenetic protocol. Changes in the architecture of eukaryotic genomes often have a major impact on processes underlying reproductive isolation, adaptation and diversification. African annual killifishes of the genus Nothobranchius Peters, 1868 (Teleostei: Nothobranchiidae), which are adapted to an extreme environment of ephemeral wetland pools in African savannahs, feature extensive karyotype evolution in small, isolated populations and thus are suitable models for studying the interplay between karyotype change and species evolution. The present investigation reveals a highly conserved diploid chromosome number (2n = 36) but a variable number of chromosomal arms (46–64) among members of the N. ugandensis species group, implying a significant role of pericentric inversions and/or other types of centromeric shift in the karyotype evolution of the group. When superimposed onto a phylogenetic tree based on molecular analyses of two mitochondrial genes the cytogenetic characteristics did not show any correlation with the phylogenetic relationships within the lineage. While karyotypes of many other Nothobranchius spp. studied to date diversified mainly via chromosome fusions and fissions, the N. ugandensis species group maintains stable 2n and the karyotype differentiation seems to be constrained to intrachromosomal rearrangements. Possible reasons for this difference in the trajectory of karyotype differentiation are discussed. While genetic drift seems to be a major factor in the fixation of chromosome rearrangements in Nothobranchius, future studies are needed to assess the impact of predicted multiple inversions on the genome evolution and species diversification within the N. ugandensis species group.
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Krysanov, Eugene Yu., Béla Nagy, Brian R. Watters, Alexandr Sember, and Sergey A. Simanovsky. "Karyotype differentiation in the Nothobranchius ugandensis species group (Teleostei, Cyprinodontiformes), seasonal fishes from the east African inland plateau, in the context of phylogeny and biogeography." Comparative Cytogenetics 17, no. (1) (2023): 13–29. https://doi.org/10.3897/compcytogen.v7.i1.97165.
Full textAbstract:
The karyotype differentiation of the twelve known members of the Nothobranchius ugandensis Wildekamp, 1994 species group is reviewed and the karyotype composition of seven of its species is described herein for the first time using a conventional cytogenetic protocol. Changes in the architecture of eukaryotic genomes often have a major impact on processes underlying reproductive isolation, adaptation and diversification. African annual killifishes of the genus Nothobranchius Peters, 1868 (Teleostei: Nothobranchiidae), which are adapted to an extreme environment of ephemeral wetland pools in African savannahs, feature extensive karyotype evolution in small, isolated populations and thus are suitable models for studying the interplay between karyotype change and species evolution. The present investigation reveals a highly conserved diploid chromosome number (2n = 36) but a variable number of chromosomal arms (46–64) among members of the N. ugandensis species group, implying a significant role of pericentric inversions and/or other types of centromeric shift in the karyotype evolution of the group. When superimposed onto a phylogenetic tree based on molecular analyses of two mitochondrial genes the cytogenetic characteristics did not show any correlation with the phylogenetic relationships within the lineage. While karyotypes of many other Nothobranchius spp. studied to date diversified mainly via chromosome fusions and fissions, the N. ugandensis species group maintains stable 2n and the karyotype differentiation seems to be constrained to intrachromosomal rearrangements. Possible reasons for this difference in the trajectory of karyotype differentiation are discussed. While genetic drift seems to be a major factor in the fixation of chromosome rearrangements in Nothobranchius, future studies are needed to assess the impact of predicted multiple inversions on the genome evolution and species diversification within the N. ugandensis species group.
Dissertations / Theses on the topic "Karyotype differentiation"
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Araujo, Douglas de. "Citogenética de 13 espécies de aranhas haploginas pertencentes às famílias Pholcidae, Sicariidae e Scytodidae (Araneomorphae) : evolução cromossômica, sistema cromossômico de determinação sexual e citotaxonomia /." Rio Claro : [s.n.], 2007. http://hdl.handle.net/11449/100530.
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Orientador: Doralice Maria Cella<br>Banca: Carlos Ribeiro Vilela<br>Banca: Claudio Juan Bidau<br>Banca: Francisco de Assis Ganeo de Mello<br>Banca: Luciana Bolsoni Lourenço<br>Resumo: Dentre todas as ordens de aracnideos conhecidas taxonomicamente, Araneae e a segunda mais diversa, com numero de especies menor somente em relacao a Acari. Atualmente, 39.725 especies ja foram descritas, sendo que centenas de novas descricoes sao feitas a cada ano em diversas familias de aranhas. O conhecimento citogenetico sobre a ordem restringe-se a analise de 638 especies (ca 2%) do total descrito do ponto de vista taxonomico. Este trabalho tem como objetivos fornecer uma compilacao dos dados citogeneticos existentes para a ordem na literatura ate a presente data, bem como caracterizar e estabelecer as estrategias de diferenciacao cromossomica em 13 especies de aranhas pertencentes ao grupo das haploginas, clado que corresponde a somente 3.257 especies (ca 8%) do total da ordem e a apenas 41 especies (ca 6%) do total cariotipado ate os dias atuais. Aliado a baixa representatividade dos dados cariologicos, outros pontos que fazem das haploginas um grupo interessante para estudos sao a predominancia de cromossomos meta/submetacentricos e de sistemas cromossomicos de determinacao sexual simples e multiplos, muitas vezes incluindo um cromossomo Y, ambas caracteristicas raras entre os outros clados de Araneae. As especies analisadas pertencem a tres familias de haploginas, Pholcidae (Mesabolivar luteus e Micropholcus fauroti), Sicariidae (Loxosceles amazonica, Loxosceles gaucho, Loxosceles hirsuta, Loxosceles intermedia, Loxosceles laeta, Loxosceles puortoi, Loxosceles similis e Sicarius tropicus) e Scytodidae (Scytodes fusca, Scytodes globula e Scytodes itapevi). Em Pholcidae, os resultados ineditos para os dois generos mostraram ... (Resumo completo, clicar acesso eletrônico abaixo)<br>Abstract: Mesabolivar luteus (Keyserling 1891) and Micropholcus fauroti (Simon 1887) specimens were collected in Ubatuba and Rio Claro, both in the state of São Paulo, Brazil. Mesabolivar luteus showed 2n(.) = 15 = 14 + X and 2n(.) = 16 = 14 + XX in mitotic metaphases and 7II + X in diplotenic cells. During late prophase I, all bivalents presented a ring shape, evidencing two chiasmata per bivalent. In this species, some diplotenic cells appear in pairs, maybe due to specific characteristics of the intercellular bridges. The metaphases II showed n = 7 or n = 8 = 7 + X chromosomes. Micropholcus fauroti evidenced 2n(.) = 17 = 16 + X in spermatogonial metaphases and 8II+X in diplotenic cells, with only one chiasma per bivalent, contrasting with M. luteus. In both species, all chromosomes were metacentrics. The X sexual chromosome was the largest element and appeared as a univalent during meiosis I. These are the first cytogenetical data for the genera Mesabolivar and Micropholcus. Additionally, M. luteus is the first chromosomally analyzed species of the New World clade and the observed diploid number for M. fauroti had not yet been recorded in Pholcidae.<br>Doutor
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Wolski, Michele Andressa Vier. "INFERÊNCIAS EVOLUTIVAS PARA DUAS ESPÉCIES DO GÊNERO Omophoita (COLEOPTERA, CHRYSOMELIDAE): DIFERENCIAÇÃO CARIOTÍPICA E MOLECULAR." Universidade Estadual de Ponta Grossa, 2014. http://tede2.uepg.br/jspui/handle/prefix/2387.
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Previous issue date: 2014-02-25<br>Coordenação de Aperfeiçoamento de Pessoal de Nível Superior<br>Alticinae apresenta características cariotípicas muito interessantes quanto a
variação do número diplóide, do sistema de determinação sexual e irregularidades
meióticas. O número cromossômico mais frequente é de 11 ou 12 pares. As
espécies de Oedionychina estudadas citogeneticamente possuem 2n= 22,10II+X+Y
com cromossomos sexuais gigantes. No que se refere à posição sistemática existem
muitas divergências entre os estudos e problemas de identificação das espécies
pertencentes aos vários gêneros. O estudo com técnicas mais refinadas e o
mapeamento do DNA r 5S é recente em Coleoptera, e as poucas espécies de
Alticinae estudadas mostram a presença de dois ou três pares autossômicos. Assim,
este trabalho tem o objetivo de analisar citogeneticamente e propor as estratégias de
diferenciação cariotípica para as espécies de Omophoita communis e Omophoita
sexnotata. A análise citogenética dos indivíduos de duas populações de O.
communis estudadas mostrou a ocorrência de grande variação no número diploide e
morfologia cromossômica, sendo possível separá-las em dois citótipos. O citótipo I
possui 2n= 22 e o citótipo II 2n= 12, sendo essa variação é descrita pela primeira
vez no gênero. Adicionalmente, o estudo da morfologia do edeago mostrou
diferenças, indicando um provável padrão de diferenciação das duas espécies. A
análise da árvore consenso da reconstrução filogenética também evidencia que os
citótipos mostram agrupamentos diferentes e reforçam a hipótese de duas espécies.
O estudo do mapeamento do gene DNAr 5S em O. sexnotata evidenciou a presença
desse cluster em todos os cromossomos autossômicos, sendo esse padrão de
dispersão nunca descrito em Coleoptera. Na literatura, a dispersão dos genes
ribossomais está sempre relacionada com a presença de elementos transponíveis.
O resultado do sequenciamento dos fragmentos de 5S ribossomal obtidos de cada
cromossomo de O. sexnotata resultaram em sequencias similares a RNAr 5S de
Drosophila melanogaster, elemento transponível EnSpm, retropseudogene de 5S e
microssatélite. Adicionalmente, a analise da estrutura secundaria do RNAr 5S,
mostrou que as sequencias obtidas não são funcionais quando comparadas seus
percentuais de energia livre em relação ao percentual da sequencia original do RNAr
5S.<br>Alticinae presents karyotypic characteristics very interesting as the variation of
the diploid number, sex determination system and meiotic irregularities. The most
frequent chromosome number is 11 or 12 pairs. The species cytogenetically studied
Oedionychina have 2n = 22,10 II + X + Y with giant sex chromosomes. In relation to
the systematic position there are many divergence between the studies and
problems of identification of species belonging to several genera. The study with
more refined techniques and rDNA 5s mapping is recent in Coleoptera , and the few
Alticinae species studied show the presence of two or three autosomal pairs. Thus,
this study aims to analyze cytogenetically and propose strategies for the species
karyotype differentiation of Omophoita communis and Omophoita sexnotata.
Cytogenetic analysis of individuals of both populations of O. communis showed the
existence of a large variation in diploid number and chromosome morphology, being
possible to separate them into two cytotypes. Cytotype I presented 2n = 22 and
cytotype II 2n = 12, this variation is described for the first time in the genus.
Additionally, the study of the morphology of the aedeagus showed differences,
indicating a likely pattern of differentiation of the two species. The phylogenetic
reconstruction consensus tree analysis also presented that cytotypes show different
groupings and reinforce the hypothesis of two species. The 5S rDNA gene mapping
of O. sexnotata showed the presence of this cluster in all autosomes, this dispersal
pattern was never described in Coleoptera before. In the literature, the dispersion of
ribosomal genes is always associated with the presence of transposable elements.
The sequencing of 5S rRNA fragments obtained from each chromosome of O.
sexnotata resulted in similar to 5S rRNA sequences of Drosophila melanogaster
transposable element EnSpm, retropseudogene 5S and microsatellite. Additionally,
analysis of the secondary structure of 5S rRNA showed that the sequences obtained
are not functional compared their percentage of free energy with the percentage of
the original sequence of the 5S rRNA .
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Araujo, Douglas de [UNESP]. "Citogenética de 13 espécies de aranhas haploginas pertencentes às famílias Pholcidae, Sicariidae e Scytodidae (Araneomorphae): evolução cromossômica, sistema cromossômico de determinação sexual e citotaxonomia." Universidade Estadual Paulista (UNESP), 2007. http://hdl.handle.net/11449/100530.
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araujo_d_dr_rcla.pdf: 1858376 bytes, checksum: dbeb43d42be45d0e0d9524437faa5d74 (MD5)<br>Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)<br>Dentre todas as ordens de aracnideos conhecidas taxonomicamente, Araneae e a segunda mais diversa, com numero de especies menor somente em relacao a Acari. Atualmente, 39.725 especies ja foram descritas, sendo que centenas de novas descricoes sao feitas a cada ano em diversas familias de aranhas. O conhecimento citogenetico sobre a ordem restringe-se a analise de 638 especies (ca 2%) do total descrito do ponto de vista taxonomico. Este trabalho tem como objetivos fornecer uma compilacao dos dados citogeneticos existentes para a ordem na literatura ate a presente data, bem como caracterizar e estabelecer as estrategias de diferenciacao cromossomica em 13 especies de aranhas pertencentes ao grupo das haploginas, clado que corresponde a somente 3.257 especies (ca 8%) do total da ordem e a apenas 41 especies (ca 6%) do total cariotipado ate os dias atuais. Aliado a baixa representatividade dos dados cariologicos, outros pontos que fazem das haploginas um grupo interessante para estudos sao a predominancia de cromossomos meta/submetacentricos e de sistemas cromossomicos de determinacao sexual simples e multiplos, muitas vezes incluindo um cromossomo Y, ambas caracteristicas raras entre os outros clados de Araneae. As especies analisadas pertencem a tres familias de haploginas, Pholcidae (Mesabolivar luteus e Micropholcus fauroti), Sicariidae (Loxosceles amazonica, Loxosceles gaucho, Loxosceles hirsuta, Loxosceles intermedia, Loxosceles laeta, Loxosceles puortoi, Loxosceles similis e Sicarius tropicus) e Scytodidae (Scytodes fusca, Scytodes globula e Scytodes itapevi). Em Pholcidae, os resultados ineditos para os dois generos mostraram...<br>Mesabolivar luteus (Keyserling 1891) and Micropholcus fauroti (Simon 1887) specimens were collected in Ubatuba and Rio Claro, both in the state of São Paulo, Brazil. Mesabolivar luteus showed 2n(.) = 15 = 14 + X and 2n(.) = 16 = 14 + XX in mitotic metaphases and 7II + X in diplotenic cells. During late prophase I, all bivalents presented a ring shape, evidencing two chiasmata per bivalent. In this species, some diplotenic cells appear in pairs, maybe due to specific characteristics of the intercellular bridges. The metaphases II showed n = 7 or n = 8 = 7 + X chromosomes. Micropholcus fauroti evidenced 2n(.) = 17 = 16 + X in spermatogonial metaphases and 8II+X in diplotenic cells, with only one chiasma per bivalent, contrasting with M. luteus. In both species, all chromosomes were metacentrics. The X sexual chromosome was the largest element and appeared as a univalent during meiosis I. These are the first cytogenetical data for the genera Mesabolivar and Micropholcus. Additionally, M. luteus is the first chromosomally analyzed species of the New World clade and the observed diploid number for M. fauroti had not yet been recorded in Pholcidae.
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Umphrey, Gary John Carleton University Dissertation Biology. "Differentiation of sibling species in the ant genus Aphaenogaster; karyotypic, electrophoretic, and morphometric investigations of the Fulva-Rudis-Texana complex." Ottawa, 1992.
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Sember, Alexandr. "Cytogenetika vybraných skupin paprskoploutvých ryb (Actinopterygii): Evolučně -ekologické aspekty spjaté s dynamikou repetitivních sekvencí a s výskytem polyploidie." Doctoral thesis, 2016. http://www.nusl.cz/ntk/nusl-348963.
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Ray-finned fishes (Actinopterygii) exhibit the greatest biodiversity among vertebrates. The vast majority of extant actinopterygian fish species belong to clade Teleostei - a lineage whose significant evolutionary success might have resulted from a teleost specific whole- genome duplication (TSGD) that occurred at the onset of this group, subsequent to its divergence from the rest of actinopterygian lineages. Despite the growing body of sequenced fish genomes and analyses of their transcriptomes, the largest contribution to understanding fish genomes comes from analyses of DNA content and from cytogenetics. Genomes of ray-finned fishes and especially those of Teleostei exhibit vast diversity and rapid dynamics of repetitive DNA sequences whose variability is reflected in a wide range of fish genome sizes and in the dynamics behind karyotype differentiation. Therefore, ray-finned fishes offer a unique opportunity to study genome variability as a driving force underlying morphological and ecological diversification, evolution and adaptation. Particularly, the mapping of repetitive DNA sequences by means of fluorescence in situ hybridization (FISH) has proven to be a very useful and informative approach during the last two decades and contributed greatly to our understanding of the fish genome...
Book chapters on the topic "Karyotype differentiation"
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Kumar, Sanjay, Asikho Kiso, and N. Abenthung Kithan. "Chromosome Banding and Mechanism of Chromosome Aberrations." In Cytogenetics - Classical and Molecular Strategies for Analysing Heredity Material. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.96242.
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Chromosome identification depends on the morphological features of the chromosome and therefore karyotype and its banding pattern analyses are the most suitable technique to identify each and every chromosome of a chromosome complement. Moreover, aberrations caused by breaks play an important role in the evolution of a chromosome set and chromosome complement by decreasing or increasing the chromosome number. Therefore, both the aspects are discussed in detail in the present chapter. At present, the chapter will highlight the karyotype and its components, karyotype trends, evolution and its role in speciation, banding pattern and techniques, chromosome differentiation and linearization, banding applications and their uses, detection and analysis of chromosomal aberrations, chromosome and chromatid types of aberrations and mechanism of the formation of chromosome aberrations and breaks for karyotype evolutionary trends.
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Meschede, Dieter, and Eberhard Nieschlag. "XX male." In Oxford Textbook of Endocrinology and Diabetes. Oxford University Press, 2011. http://dx.doi.org/10.1093/med/9780199235292.003.9079.
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This disorder is characterized by the combination of male external genitalia, testicular differentiation of the gonads, and an apparent 46,XX karyotype. Designation of the karyotype as 46,XX is based on conventional cytogenetic analysis, where the X chromosomes have an inconspicuous appearance. If molecular methods are applied, most XX males can be shown to have translocated Y-chromosomal material on the tip of one X chromosome. Strictly speaking, the karyotype of these patients should be written as 46,X,der(X)t(Xp;Yp). It has been suggested that this disorder be renamed ‘46,XX testicular disorder of sex development’ (1). The authors prefer to stay with the the less clumsy ‘XX male (syndrome)’.
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Ahmed, S. Faisal, and Angela K. Lucas-Herald. "Normal and abnormal sexual differentiation." In Oxford Textbook of Medicine, edited by Mark Gurnell. Oxford University Press, 2020. http://dx.doi.org/10.1093/med/9780198746690.003.0257.
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Human sex development follows an orderly sequence of embryological events coordinated by a cascade of gene expression and hormone production in a time- and concentration-dependent manner. Underpinning the entire process of fetal sex development is the simple mantra: sex chromosomes (XX or XY) dictate the gonadotype (ovary or testis), which then dictates the somatotype (female or male phenotype). The constitutive sex in fetal development is female. Disorders of sex development (DSD) can be classified into three broad categories based on the knowledge of the karyotype: sex chromosome abnormality (e.g. X/XY, mixed gonadal dysgenesis); XX DSD (e.g. congenital adrenal hyperplasia); XY DSD (e.g. partial androgen insensitivity syndrome).
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"Cutthroat Trout: Evolutionary Biology and Taxonomy." In Cutthroat Trout: Evolutionary Biology and Taxonomy, edited by Dennis K. Shiozawa, R. Paul Evans, Derek D. Houston, and Peter J. Unmack. American Fisheries Society, 2018. http://dx.doi.org/10.47886/9781934874509.ch6.
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<em>Abstract</em>.—North American trout have undergone a long and complicated taxonomic history and this holds for taxonomic designations of Cutthroat Trout <em>Oncorhynchus clarkii</em>. Current Cutthroat Trout taxonomy recognizes a monophyletic species comprising 11–16 subspecies. The complex geological and climatic history of western North America is postulated to have strongly influenced differentiation among Cutthroat Trout subspecies. Early studies relied on morphological and meristic data in conjunction with fossil data and known aquatic connections within and among hydrological basins to infer the phylogenetic history of Cutthroat Trout. More recently, molecular studies incorporating karyotypes, allozymes, restriction fragment length polymorphisms, and mitochondrial DNA (mtDNA) sequence data have tested these early phylogenetic hypotheses and yielded additional insights into Cutthroat Trout evolution, although some phylogenetic relationships remain unresolved. In this study, we analyzed DNA sequence data from approximately half of the mitochondrial genome (8,057 base pairs) to better resolve phylogenetic relationships and estimate divergence times among Cutthroat Trout lineages. Herein, we present a well-resolved mtDNA phylogeny and discuss Cutthroat Trout evolution in a phylogeographic framework, as well as clarify current taxonomic implications and make recommendations for future research directions.
Conference papers on the topic "Karyotype differentiation"
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Разумова, О. В., Ю. В. Бочаркина, К. Д. Боне, Д. В. Романов, А. А. Почтовый, and О. С. Александров. "COMPARATIVE ANALYSIS OF REPEATING DNA FRACTIONS IN PLANTS OF THE FAMILY CANNABACEAE AND ITS ROLE IN DIFFERENTIATION OF SEX CHROMOSOMES." In Биотехнология в растениеводстве, животноводстве и сельскохозяйственной микробиологии. Crossref, 2021. http://dx.doi.org/10.48397/arriab.2021.21.xxi.067.
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Семейство Cannabaceae sensu stricto включает два рода - род Humulus и род Cannabis с единственным крайне полиморфным видом Cannabis sativa. Характерной особенностью растений данных родов является наличие в кариотипе у всех видов гетероморфных половых хромосом, что является чрезвычайно редким явлением в царстве растений, при этом данные хромосомы различны у разных видов: XX/ XY с большой Y-хромосомой у конопли посевной, XX/XY с маленькой Y-хромосомой у хмеля обыкновенного и мультихромосомная система с большими половыми хромосомами XX/XY1Y2 у хмеля японского. Такое разнообразие типов половых хромосом в пределах одного семейства открывает широкие возможности для изучения эволюции пола в целом, поскольку ранее показано, что размер и количество половых хромосом у растений связано с эволюционной древностью или молодостью вида (Ming et al., 2011). The family Cannabaceae sensu stricto includes two genera, the genus Humulus and the genus Cannabis, with a single extremely polymorphic species, Cannabis sativa. A characteristic feature of plants of these genera is the presence in the karyotype of all species of heteromorphic sex chromosomes, which is an extremely rare occurrence in the plant kingdom, while these chromosomes are different in different species: XX/XY with a large Y-chromosome in cannabis, XX/XY with a small Y-chromosome in common hop and a multichromosome system with large XX/XY1Y2 sex chromosomes in Japanese hop. Such a variety of sex chromosome types within the same family opens up wide opportunities for studying the evolution of sex in general, since it was previously shown that the size and number of sex chromosomes in plants is associated with the evolutionary antiquity or youth of the species (Ming et al., 2011).