scholarly journals Genomic Organization of Repetitive DNA Elements and Extensive Karyotype Diversity of Silurid Catfishes (Teleostei: Siluriformes): A Comparative Cytogenetic Approach

2019 ◽  
Vol 20 (14) ◽  
pp. 3545
Author(s):  
Sukhonthip Ditcharoen ◽  
Luiz Antonio Carlos Bertollo ◽  
Petr Ráb ◽  
Eva Hnátková ◽  
Wagner Franco Molina ◽  
...  
Keyword(s):  
Evolutionary Dynamics ◽  
Chromosomal Rearrangements ◽  
5S Rdna ◽  
Comparative Genomic ◽  
Molecular Cytogenetic ◽  
Rdna Sites ◽  
Genomic Divergence ◽  
Fish Chromosomes ◽  
Dna Elements ◽  
Repetitive Dna Elements

The catfish family Siluridae contains 107 described species distributed in Asia, but with some distributed in Europe. In this study, karyotypes and other chromosomal characteristics of 15 species from eight genera were examined using conventional and molecular cytogenetic protocols. Our results showed the diploid number (2n) to be highly divergent among species, ranging from 2n = 40 to 92, with the modal frequency comprising 56 to 64 chromosomes. Accordingly, the ratio of uni- and bi-armed chromosomes is also highly variable, thus suggesting extensive chromosomal rearrangements. Only one chromosome pair bearing major rDNA sites occurs in most species, except for Wallago micropogon, Ompok siluroides, and Kryptoterus giminus with two; and Silurichthys phaiosoma with five such pairs. In contrast, chromosomes bearing 5S rDNA sites range from one to as high as nine pairs among the species. Comparative genomic hybridization (CGH) experiments evidenced large genomic divergence, even between congeneric species. As a whole, we conclude that karyotype features and chromosomal diversity of the silurid catfishes are unusually extensive, but parallel some other catfish lineages and primary freshwater fish groups, thus making silurids an important model for investigating the evolutionary dynamics of fish chromosomes.

Effects of the diploidisation process upon the 5S and 35S rDNA sequences in the allopolyploid species of the Dilatata group of Paspalum (Poaceae, Paniceae)

2019 ◽  
Vol 67 (7) ◽  
pp. 521
Author(s):  
Magdalena Vaio ◽  
Cristina Mazzella ◽  
Marcelo Guerra ◽  
Pablo Speranza
Keyword(s):  
Evolutionary Dynamics ◽  
In Situ Hybridisation ◽  
5S Rdna ◽  
Its Region ◽  
Variable Number ◽  
Rrna Genes ◽  
Fluorescence In Situ Hybridisation ◽  
Rdna Sites ◽  
35S Rdna ◽  
Genome Restructuring

The Dilatata group of Paspalum includes species and biotypes native to temperate South America. Among them, five sexual allotetraploids (x = 10) share the same IIJJ genome formula: P. urvillei Steud, P. dasypleurum Kunze ex Desv., P. dilatatum subsp. flavescens Roseng., B.R. Arrill. & Izag., and two biotypes P. dilatatum Vacaria and P. dilatatum Virasoro. Previous studies suggested P. intermedium Munro ex Morong & Britton and P. juergensii Hack. or related species as their putative progenitors and donors of the I and J genome, respectively, and pointed to a narrow genetic base for their maternal origin. It has not yet been established whether the various members of the Dilatata group are the result of a single or of multiple allopolyploid formations. Here, we aimed to study the evolutionary dynamics of rRNA genes after allopolyploidisation in the Dilatata group of Paspalum and shed some light into the genome restructuring of the tetraploid taxa with the same genome formula. We used double target fluorescence in situ hybridisation of 35S and 5S rDNA probes and sequenced the nrDNA internal transcribed spacer (ITS) region. A variable number of loci at the chromosome ends were observed for the 35S rDNA, from 2 to 6, suggesting gain and loss of sites. For the 5S rDNA, only one centromeric pair of signals was observed, indicating a remarkable loss after polyploidisation. All ITS sequences generated were near identical to the one found for P. intermedium. Although sequences showed a directional homogeneisation towards the putative paternal progenitor in all tetraploid species, the observed differences in the number and loss of rDNA sites suggest independent ongoing diploidisation processes in all taxa and genome restructuring following polyploidy.

scholarly journals Cytogenetics of two Farlowella species (Loricariidae: Loricariinae): implications on the taxonomic status of the species

2018 ◽  
Vol 16 (4) ◽  
Author(s):  
Leandro Marajó ◽  
Patrik F. Viana ◽  
Milena Ferreira ◽  
Lúcia H. Rapp Py-Daniel ◽  
Eliana Feldberg
Keyword(s):  
Chromosome Number ◽  
Species Complex ◽  
Chromosomal Rearrangements ◽  
5S Rdna ◽  
Taxonomic Status ◽  
Specific Marker ◽  
Genetic Studies ◽  
Molecular Cytogenetic ◽  
Metacentric Pair ◽  
Species Specific

ABSTRACT Farlowella is one of the most diverse genera of the Loricariinae, restricted to South America rivers. The taxonomic and phylogenetic relationships among its species are contentious and, while genetic studies would contribute to the understanding of their relationships, the only available datum refer to the karyotype description of only one species. In the present study two Amazonian species, Farlowella cf. amazonum and F. schreitmuelleri, were analyzed using conventional and molecular cytogenetic procedures. Both species had diploid chromosome number 58, but different fundamental numbers (NF) 116 and 112, respectively, indicative of chromosomal rearrangements. C-banding is almost poor, especially in F. cf. amazonum, and occurs predominantly in the centromeric and in some telomeric regions, although genome of F. schreitmuelleri possessed a much larger heterochromatin amount then those of F. cf. amazonum. The chromosomes bearing the NOR sites were likely the same for both species, corresponding to the 1st metacentric pair in F. cf. amazonum and to the 28th acrocentric in F. schreitmuelleri. The location of the 5S rDNA was species-specific marker. This study expanded the available cytogenetic data for Farlowella species and pointed the remarkable karyotype diversity among species/populations, indicating a possible species complex within genus.

scholarly journals Microstructural chromosome reorganization in the genus Trichomycterus (Siluriformes: Trichomycteridae)

2016 ◽  
Vol 14 (2) ◽  
Author(s):  
Maria Lígia M. de Oliveira ◽  
Ricardo Utsunomia ◽  
José Carlos Pansonato-Alves ◽  
Priscilla C. Scacchetti ◽  
Cleberson C. Primo ◽  
...  
Keyword(s):  
Chromosome Number ◽  
Constitutive Heterochromatin ◽  
Genomic Structure ◽  
5S Rdna ◽  
Ribosomal Genes ◽  
Molecular Cytogenetic ◽  
Rdna Sites ◽  
Karyotype Formula ◽  
Molecular Cytogenetic Techniques ◽  
Genomic Reorganization

Trichomycterus is a specious fish genus within Trichomycterinae and displays remarkable karyotype diversity. However, knowledge about their genomic structure and location of repetitive sequence is still limited. In order to better understand the karyotype diversification, we analyzed nine species of Trichomycterus using classical and molecular cytogenetic techniques. Results revealed a conserved diploid chromosome number of 2n=54 chromosomes in all analyzed species, although remarkable differences on the constitutive heterochromatin distribution were observed. In addition, while the 18S rDNA showed a conserved distribution pattern, the 5S rDNA sites showed a quite diverse location considering the analyzed species. Remarkably, both ribosomal genes were co-located in all species, except in T . iheringi , suggesting that co-localization is probably an ancestral condition in Trichomycterus . Finally, three analyzed species showed heterochromatic B chromosomes, reinforcing the intense genomic reorganization occurring in Trichomycterus . Our results showed that chromosomal variations are not restricted to differences in karyotype formula as previously proposed, but also to modifications on the microstructural level of resolution.

Evolutionary Dynamics of 5S rDNA and Recurrent Association of Transposable Elements in Electric Fish of the Family Gymnotidae (Gymnotiformes): The Case of Gymnotus mamiraua

2016 ◽  
Vol 149 (4) ◽  
pp. 297-303 ◽  
Author(s):  
Maelin da Silva ◽  
Patricia Barbosa ◽  
Roberto F. Artoni ◽  
Eliana Feldberg
Keyword(s):  
Electric Fish ◽  
Evolutionary Dynamics ◽  
Chromosomal Location ◽  
Molecular Mapping ◽  
5S Rdna ◽  
Mapping Data ◽  
Rdna Sequences ◽  
Rdna Sites ◽  
The Family

Gymnotidae is a family of electric fish endemic to the Neotropics consisting of 2 genera: Electrophorus and Gymnotus. The genus Gymnotus is widely distributed and is found in all of the major Brazilian river systems. Physical and molecular mapping data for the ribosomal DNA (rDNA) in this genus are still scarce, with its chromosomal location known in only 11 species. As other species of Gymnotus with 2n = 54 chromosomes from the Paraná-Paraguay basin, G. mamiraua was found to have a large number of 5S rDNA sites. Isolation and cloning of the 5S rDNA sequences from G. mamiraua identified a fragment of a transposable element similar to the Tc1/mariner transposon associated with a non-transcribed spacer. Double fluorescence in situ hybridization analysis of this element and the 5S rDNA showed that they were colocalized on several chromosomes, in addition to acting as nonsyntenic markers on others. Our data show the association between these sequences and suggest that the Tc1 retrotransposon may be the agent that drives the spread of these 5S rDNA-like sequences in the G. mamiraua genome.

scholarly journals Comparative cytogenetic analyses in Ancistrus species (Siluriformes: Loricariidae)

2020 ◽  
Vol 18 (2) ◽  
Author(s):  
Larissa Glugoski ◽  
Geize Deon ◽  
Stephane Schott ◽  
Marcelo R. Vicari ◽  
Viviane Nogaroto ◽  
...  
Keyword(s):  
Chromosomal Rearrangements ◽  
5S Rdna ◽  
Chromosomal Evolution ◽  
Sister Group ◽  
Fusion Event ◽  
Rdna Cluster ◽  
Strand Breaks ◽  
Rdna Sites ◽  
Cytogenetic Analyses ◽  
Ribosomal Dnas

ABSTRACT Ancistrus is a specious genus of armored catfishes that has been extensively used for cytogenetic studies in the last 17 years. A comparison of the extensive karyotypic plasticity within this genus is presented with new cytogenetic analysis for Ancistrus cf. multispinis and Ancistrus aguaboensis. This study aims to improve our understanding of chromosomal evolution associated with changes in the diploid number (2n) and the dispersion of ribosomal DNAs (rDNAs) within Ancistrus. Ancistrus cf. multispinis and A. aguaboensis exhibit 2n of 52 and 50 chromosomes, respectively. Given that A. cf. multispinis shares a 2n = 52 also found in Pterygoplichthyini, the sister group for Ancistrini, a Robertsonian (Rb) fusion event is proposed for the 2n reduction in A. aguaboensis. 5S rDNAs pseudogenes sites have already been associated with Rb fusion in Ancistrus and our analysis suggests that the 2n reduction in A. aguaboensis was triggered by double strand breaks (DSBs) and chromosomal rearrangements at 5S rDNA sites. The presence of evolutionary breakpoint regions (EBRs) into rDNA cluster is proposed to explain part of the Rb fusion in Ancistrus. Cytogenetic data presented extends the diversity already documented in Ancistrus to further understand the role of chromosomal rearrangements in the diversification of Ancistrini.

Chromosomal Mapping of Repeat DNA in Bergiaria westermanni (Pimelodidae, Siluriformes): Localization of 45S rDNA in B Chromosomes

2018 ◽  
Vol 154 (2) ◽  
pp. 99-106 ◽  
Author(s):  
Geovana C. Malimpensa ◽  
Josiane B. Traldi ◽  
Danyelle Toyama ◽  
Flávio Henrique-Silva ◽  
Marcelo R. Vicari ◽  
...  
Keyword(s):  
Chromosomal Rearrangements ◽  
Indirect Evidence ◽  
5S Rdna ◽  
B Chromosomes ◽  
Chromosomal Mapping ◽  
Interindividual Variation ◽  
Rrna Genes ◽  
45S Rdna ◽  
Rdna Sites ◽  
Repeat Dna

The occurrence of repetitive DNA in autosomes and B chromosomes of Bergiaria westermanni was examined using conventional and molecular cytogenetic techniques. This species exhibited 2n = 56 chromosomes, with intra- and interindividual variation in the number of heterochromatic B chromosomes (from 0 to 4). The 5S rDNA was localized in pairs 1 and 5, and histone probes (H1, H3, and H4) and U2 small nuclear RNA were syntenic with 5S rDNA in pair 5. Histone sequences were also located in chromosome pair 14. The (GATA)n sequence was dispersed throughout the autosomes and B chromosomes, with clusters (microsatellite accumulation) in some chromosome regions. The telomeric probe revealed no signs of chromosomal rearrangements in the genome of B. westermanni. The 45S rDNA sites were detected in the terminal region of pair 27; these sites corresponded to a GC-rich heterochromatin block. In addition, 3 of the 4 B chromosomes also contained 45S rDNA copies. Silver nitrate staining in interphase nuclei provided indirect evidence of the expression of these rRNA genes in B chromosomes, indicating the probable origin of these elements. This report shows plasticity in the chromosomal localization of repeat DNA in B. westermanni and features a discussion of genomic diversification.

scholarly journals Comparative cytogenetic survey of the giant bonytongue Arapaima fish (Osteoglossiformes: Arapaimidae), across different Amazonian and Tocantins/Araguaia River basins

2020 ◽  
Vol 18 (4) ◽  
Author(s):  
Ezequiel A. de Oliveira ◽  
Francisco de M. C. Sassi ◽  
Manolo F. Perez ◽  
Luiz A. C. Bertollo ◽  
Petr Ráb ◽  
...  
Keyword(s):  
River Basins ◽  
Comparative Genomic ◽  
South American ◽  
Molecular Cytogenetic ◽  
Araguaia River ◽  
Rdna Sites ◽  
Cytogenetic Survey ◽  
Acrocentric Chromosomes ◽  
Great Portion

Abstract The South American giant fishes of the genus Arapaima, commonly known as pirarucu, are one of the most iconic among Osteoglossiformes. Previously cytogenetic studies have identified their karyotype characteristics; however, characterization of cytotaxonomic differentiation across their distribution range remains unknown. In this study, we compared chromosomal characteristics using conventional and molecular cytogenetic protocols in pirarucu populations from the Amazon and Tocantins-Araguaia river basins to verify if there is differentiation among representatives of this genus. Our data revealed that individuals from all populations present the same diploid chromosome number 2n=56 and karyotype composed of 14 pairs of meta- to submetacentric and 14 pairs of subtelo- to acrocentric chromosomes. The minor and major rDNA sites are in separate chromosomal pairs, in which major rDNA sites corresponds to large heterochromatic blocks. Comparative genomic hybridizations (CGH) showed that the genome of these populations shared a great portion of repetitive elements, due to a lack of substantial specific signals. Our comparative cytogenetic data analysis of pirarucu suggested that, although significant genetic differences occur among populations, their general karyotype patterns remain conserved.

scholarly journals Tracking the Evolutionary Trends Among Small-Size Fishes of the Genus Pyrrhulina (Characiforme, Lebiasinidae): New Insights From a Molecular Cytogenetic Perspective

2021 ◽  
Vol 12 ◽  
Author(s):  
Renata Luiza Rosa de Moraes ◽  
Francisco de Menezes Cavalcante Sassi ◽  
Luiz Antonio Carlos Bertollo ◽  
Manoela Maria Ferreira Marinho ◽  
Patrik Ferreira Viana ◽  
...  
Keyword(s):  
Repetitive Dna ◽  
Sex Chromosome ◽  
Comparative Genomic ◽  
Comparative Genome Hybridization ◽  
Molecular Cytogenetic ◽  
Rdna Sites ◽  
Previous Hypothesis ◽  
History Of ◽  
Cytogenetic Analyses ◽  
High Dynamics

Miniature fishes have always been a challenge for cytogenetic studies due to the difficulty in obtaining chromosomal preparations, making them virtually unexplored. An example of this scenario relies on members of the family Lebiasinidae which include miniature to medium-sized, poorly known species, until very recently. The present study is part of undergoing major cytogenetic advances seeking to elucidate the evolutionary history of lebiasinids. Aiming to examine the karyotype diversification more deeply in Pyrrhulina, here we combined classical and molecular cytogenetic analyses, including Giemsa staining, C-banding, repetitive DNA mapping, comparative genomic hybridization (CGH), and whole chromosome painting (WCP) to perform the first analyses in five Pyrrhulina species (Pyrrhulina aff. marilynae, Pyrrhulina sp., P. obermulleri, P. marilynae and Pyrrhulina cf. laeta). The diploid number (2n) ranged from 40 to 42 chromosomes among all analyzed species, but P. marilynae is strikingly differentiated by having 2n = 32 chromosomes and a karyotype composed of large meta/submetacentric chromosomes, whose plesiomorphic status is discussed. The distribution of microsatellites does not markedly differ among species, but the number and position of the rDNA sites underwent significant changes among them. Interspecific comparative genome hybridization (CGH) found a moderate divergence in the repetitive DNA content among the species’ genomes. Noteworthy, the WCP reinforced our previous hypothesis on the origin of the X1X2Y multiple sex chromosome system in P. semifasciata. In summary, our data suggest that the karyotype differentiation in Pyrrhulina has been driven by major structural rearrangements, accompanied by high dynamics of repetitive DNAs.

scholarly journals Adding New Pieces to the Puzzle of Karyotype Evolution in Harttia (Siluriformes, Loricariidae): Investigation of Amazonian Species

Biology ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 922
Author(s):  
Francisco de M. C. Sassi ◽  
Orlando Moreira-Filho ◽  
Geize A. Deon ◽  
Alexandr Sember ◽  
Luiz A. C. Bertollo ◽  
...  
Keyword(s):  
Sex Chromosomes ◽  
Sex Chromosome ◽  
5S Rdna ◽  
Morphological Diversity ◽  
High Rate ◽  
Comparative Genomic ◽  
Chromosomal Distribution ◽  
Single Chromosome ◽  
Male Genome ◽  
Rdna Sites

A remarkable morphological diversity and karyotype variability can be observed in the Neotropical armored catfish genus Harttia. These fishes offer a useful model to explore both the evolution of karyotypes and sex chromosomes, since many species possess male-heterogametic sex chromosome systems and a high rate of karyotype repatterning. Based on the karyotype organization, the chromosomal distribution of several repetitive DNA classes, and the rough estimates of genomic divergences at the intraspecific and interspecific levels via Comparative Genomic Hybridization, we identified shared diploid chromosome numbers (2n = 54) but different karyotype compositions in H. dissidens (20m + 26sm + 8a) and Harttia sp. 3 (16m + 18sm + 14st + 6a), and different 2n in H. guianensis (2n = 58; 20m + 26sm + 2st + 10a). All species further displayed similar patterns of chromosomal distribution concerning constitutive heterochromatin, 18S ribosomal DNA (rDNA) sites, and most of the surveyed microsatellite motifs. Furthermore, differences in the distribution of 5S rDNA sites and a subset of microsatellite sequences were identified. Heteromorphic sex chromosomes were lacking in H. dissidens and H. guianensis at the scale of our analysis. However, one single chromosome pair in Harttia sp. 3 males presented a remarkable accumulation of male genome-derived probe after CGH, pointing to a tentative region of early sex chromosome differentiation. Thus, our data support already previously outlined evidence that Harttia is a vital model for the investigation of teleost karyotype and sex chromosome dynamics.

scholarly journals Molecular cytogenetic characterization and phylogenetic analysis of four Miscanthus species (Poaceae)

2019 ◽  
Vol 13 (3) ◽  
pp. 211-230 ◽  
Author(s):  
Yan-Mei Tang ◽  
Liang Xiao ◽  
Yasir Iqbal ◽  
Jian-Feng Liao ◽  
Long-Qian Xiao ◽  
...  
Keyword(s):  
Genomic Dna ◽  
Phylogenetic Trees ◽  
Repetitive Sequences ◽  
Comparative Genomic ◽  
45S Rdna ◽  
Molecular Cytogenetic ◽  
Rdna Sites ◽  
Molecular Phylogenetic ◽  
Cytogenetic Characterization

Chromosomes of four Miscanthus (Andersson, 1855) species including M. sinensis (Andersson, 1855), M. floridulus (Schumann & Lauterb, 1901), M. sacchariflorus (Hackel, 1882) and M. lutarioriparius (Chen & Renvoize, 2005) were analyzed using sequentially combined PI and DAPI (CPD) staining and fluorescence in situ hybridization (FISH) with 45S rDNA probe. To elucidate the phylogenetic relationship among the four Miscanthus species, the homology of repetitive sequences among the four species was analyzed by comparative genomic in situ hybridization (cGISH). Subsequently four Miscanthus species were clustered based on the internal transcribed spacer (ITS) of 45S rDNA. Molecular cytogenetic karyotypes of the four Miscanthus species were established for the first time using chromosome measurements, fluorochrome bands and 45S rDNA FISH signals, which will provide a cytogenetic tool for the identification of these four species. All the four have the karyotype formula of Miscanthus species, which is 2n = 2x = 38 = 34m(2SAT) + 4sm, and one pair of 45S rDNA sites. The latter were shown as strong red bands by CPD staining. A non-rDNA CPD band emerged in M. floridulus and some blue DAPI bands appeared in M. sinensis and M. floridulus. The hybridization signals of M. floridulus genomic DNA to the chromosomes of M. sinensis and M. lutarioriparius genomic DNA to the chromosomes of M. sacchariflorus were stronger and more evenly distributed than other combinations. Molecular phylogenetic trees showed that M. sinensis and M. floridulus were closest relatives, and M. sacchariflorus and M. lutarioriparius were also closely related. These findings were consistent with the phylogenetic relationships inferred from the cGISH patterns.

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