Diversity of Sex Chromosome Systems in Ancistrini (Loricariidae, Hypostominae): ZZ/ZW in Ancistrus taunayi Miranda Ribeiro, 1918

The karyotype of the Ancistrini catfish Ancistrus taunayi was analyzed by conventional (Giemsa staining, AgNOR staining and C-banding) and molecular cytogenetic (5S and 18S rDNA-FISH) methods. The diploid chromosome number was 2n = 50 (22 metacentrics + 10 submetacentrics + 10 subtelocentrics + 8 acrocentrics) for both sexes. A single NOR-bearing acrocentric chromosome pair (No. 24) was detected after Ag-staining and 18S rDNA-FISH, while 5S rDNA was found only in the subtelocentric pair No. 21. Conspicuous GC-rich heterochromatin blocks corresponded to the NOR sites and were also observed in the distal regions of the acrocentric chromosome pairs Nos. 22 and 25. Chromosome pair No. 22 differed between males and females; in males, only a small interstitial block of GC-rich heterochromatin was present in both chromosomes, whereas in females, 2 blocks of GC-rich heterochromatin flanked a euchromatic region in one of the homologues, suggesting the occurrence of a ZZ/ZW sex chromosome system. Two mechanisms for the origin and evolution of this simple ZZ/ZW sex chromosome system in A. taunayi are proposed: (1) a paracentric inversion followed by amplification of the proximal heterochromatin and (2) amplification of the interstitial heterochromatin followed by a paracentric inversion. Although ZZ/ZW systems have already been described for other Ancistrus species, our results do not show the same pattern, suggesting an independent origin.

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Karyotype description of three species of Loricariidae (Siluriformes) and occurrence of the ZZ/ZW sexual system in Hemiancistrus spilomma Cardoso & Lucinda, 2003

Neotropical Ichthyology ◽

10.1590/s1679-62252006000100010 ◽

2006 ◽

Vol 4 (1) ◽

pp. 93-97 ◽

Cited By ~ 22

Author(s):

Renildo Ribeiro de Oliveira ◽

Issakar Lima Souza ◽

Paulo Cesar Venere

Keyword(s):

Chromosome Pair ◽

Sex Chromosome ◽

Sexual System ◽

Freshwater Systems ◽

Phylogenetic Studies ◽

Cytogenetic Data ◽

Sex Chromosome System

The neotropical freshwater systems have a high number of catfish species (Siluriformes), and many of those are denominated "cascudos" in Brazil. Cytogenetic data about three "cascudos" species fished in the rio Araguaia are described in the present study. The Pterygoplichthys joselimaianus showed 2n=52, with 28 metacentrics (M) chromosomes, 16 submetacentrics (SM) and 8 subtelocentrics/acrocentrics (ST/A) in both sexes. Hemiancistrus spinosissimus showed 2n=52, with karyotype formulae 26M+22SM+4ST, in both sexes. Hemiancistrusspilomma also showed 2n=52, but in this species a ZZ/ZW sex chromosome system (25M+21SM+6ST in females and 24M+22SM+6ST in males) was observed. The cells from H. spinosissimus and P. joselimaianus showed one chromosome pair bearing Ag-NORs, while in the H. spilomma three chromosome pairs bearing Ag-NORs were detected. The data showed in this work reveal particular chromosomal characteristics, important for a good recognition of both Hemincistrus species, and also show the importance of the insertion of cytogenetic data on taxonomic phylogenetic studies.

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Karyotypes of three species of Hyperophora Brunner von Wattenwyl, 1878 (Tettigoniidae, Phaneropterinae) enable morphologically similar species to be distinguished

Comparative Cytogenetics ◽

10.3897/compcytogen.v13i1.31803 ◽

2019 ◽

Vol 13 (1) ◽

pp. 87-93 ◽

Cited By ~ 1

Author(s):

Bruno Cansanção Silva ◽

Lucas Henrique Bonfim Souza ◽

Juliana Chamorro-Rengifo ◽

Douglas Araujo

Keyword(s):

Chromosome Number ◽

Diploid Number ◽

Sex Chromosome ◽

Acrocentric Chromosome ◽

Chromosome Morphology ◽

Similar Species ◽

Cerrado Biome ◽

Cytogenetic Studies ◽

Sex Chromosome System ◽

The Difference

Phaneropterinae is the largest subfamily of Tettigoniidae, distributed across the globe. There are few cytogenetic studies regarding this group, as in the case of the genus group Aniarae, which represents only two karyotyped species. The current study aims to analyze cytogenetically three species of Hyperophora Brunner von Wattenwyl, 1878 from Brazil. The male diploid number of Hyperophoraminor Brunner von Wattenwyl, 1891 and Hyperophoramajor Brunner von Wattenwyl, 1878 is 2n♂= 31, whereas Hyperophorabrasiliensis Brunner von Wattenwyl, 1878 has shown 2n♂= 29. These three species possess an X0 sex chromosome system and telo/acrocentric chromosome morphology. The only species found in the Pantanal biome, H.brasiliensis, can be chromosomally distinguished from the Cerrado biome species H.major and H.minor, due to the difference in chromosome number (2n♂= 29 and 2n♂= 31, respectively).

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In SituGene Mapping of Two Genes Supports Independent Evolution of Sex Chromosomes in Cold-Adapted Antarctic Fish

BioMed Research International ◽

10.1155/2013/243938 ◽

2013 ◽

Vol 2013 ◽

pp. 1-8 ◽

Cited By ~ 3

Author(s):

Laura Ghigliotti ◽

C.-H. Christina Cheng ◽

Céline Bonillo ◽

Jean-Pierre Coutanceau ◽

Eva Pisano

Keyword(s):

Sex Chromosome ◽

Antarctic Fish ◽

5S Rdna ◽

Cold Adapted ◽

Antifreeze Glycoprotein ◽

Y Chromosomes ◽

Pagothenia Borchgrevinki ◽

History Of ◽

Sex Chromosome System

Two genes, that is, 5S ribosomal sequences and antifreeze glycoprotein (AFGP) genes, were mapped onto chromosomes of eight Antarctic notothenioid fish possessing a X1X1X2X2/X1X2Y sex chromosome system, namely,Chionodraco hamatusandPagetopsis macropterus(family Channichthyidae),Trematomus hansoni,T. newnesi,T. nicolai,T. lepidorhinus, andPagothenia borchgrevinki(family Nototheniidae), andArtedidraco skottsbergi(family Artedidraconidae). Through fluorescencein situhybridization (FISH), we uncovered distinct differences in the gene content of the Y chromosomes in the eight species, withC. hamatusandP. macropterusstanding out among others in bearing 5S rDNA and AFGP sequences on their Y chromosomes, respectively. Both genes were absent from the Y chromosomes of any analyzed species. The distinct patterns of Y and non-Y chromosome association of the 5S rDNA and AFGP genes in species representing different Antarctic fish families support an independent origin of the sex heterochromosomes in notothenioids with interesting implications for the evolutionary/adaptational history of these fishes living in a cold-stable environment.

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Chromosomal analysis of Centromochlus heckelii (Siluriformes: Auchenipteridae), with a contribution to Centromochlus definition

Neotropical Ichthyology ◽

10.1590/1982-0224-2020-0009 ◽

2020 ◽

Vol 18 (3) ◽

Author(s):

Samantha Kowalski ◽

Leonardo Marcel Paiz ◽

Maelin da Silva ◽

Amanda de Souza Machado ◽

Eliana Feldberg ◽

...

Keyword(s):

River Basin ◽

Chromosome Pair ◽

Diploid Number ◽

Sex Chromosome ◽

Chromosomal Analysis ◽

Amazon River Basin ◽

Terminal Position ◽

Chromosomal Markers ◽

Sex Chromosome System ◽

Acrocentric Chromosomes

ABSTRACT Historically, there are divergences in the species allocation between Centromochlus and Tatia. This study aimed to generate the first cytogenetic data about Centromochlus and, by analyzing a population of Centromochlus heckelii from the Amazon River basin, to contribute as evidence to a historical taxonomic dilemma. Diploid number of 46 chromosomes and a heteromorphic pair was found in the female karyotypes, thus characterizing a ZZ/ZW sex chromosome system. Pale blocks of heterochromatin were located in centromeric regions of some chromosomes; however, the exclusive female chromosome (W) is almost entirely heterochromatic. AgNORs were detected in terminal position on the short arms of one acrocentric pair in males and two chromosome pairs in females, the acrocentric plus the sex chromosome pair. Notable differences between Centromochlus heckelii and previous data about species of Tatia are: lower diploid number, presence of a sex chromosome system and multiple AgNORs in Centromochlus, while species of Tatia have simple AgNORs and the absence of acrocentric chromosomes. Results in this study show that chromosomal markers could contribute as evidence to taxonomic delimitation studies.

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Bed bug cytogenetics: karyotype, sex chromosome system, FISH mapping of 18S rDNA, and male meiosis in Cimex lectularius Linnaeus, 1758 (Heteroptera: Cimicidae)

Comparative Cytogenetics ◽

10.3897/compcytogen.v4i2.36 ◽

2010 ◽

Vol 4 (2) ◽

pp. 151-160 ◽

Cited By ~ 26

Author(s):

Snejana Grozeva ◽

Valentina Kuznetsova ◽

B Anokhin

Keyword(s):

18S Rdna ◽

Sex Chromosome ◽

Male Meiosis ◽

Cimex Lectularius ◽

Bed Bug ◽

Fish Mapping ◽

Sex Chromosome System

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Karyotypic variation in the long-whiskered catfish Pimelodus blochii Valenciennes, 1840 (Siluriformes, Pimelodidae) from the lower Tapajós, Amazonas and Trombetas Rivers

Comparative Cytogenetics ◽

10.3897/compcytogen.v12i3.22590 ◽

2018 ◽

Vol 12 (3) ◽

pp. 285-298 ◽

Cited By ~ 1

Author(s):

Ivanny Coelho da Fonseca ◽

Luan Aércio Melo Maciel ◽

Frank Raynner Vasconcelos Ribeiro ◽

Luís Reginaldo Ribeiro Rodrigues

Keyword(s):

Silver Staining ◽

Chromosome Pair ◽

Fluorescent In Situ Hybridization ◽

Species Complex ◽

Diploid Number ◽

Acrocentric Chromosome ◽

5S Rdna ◽

Karyotypic Formula ◽

Karyotypic Variation

The genus Pimelodus LaCépède, 1803 comprises 35 formally recognized species distributed along the major neotropical river basins. Despite conservatism in diploid number with 2n=56, an intense variation of chromosomal morphology (karyotypic formula) has been documented in Pimelodus species. In the present study, we analyzed karyotypes of 20 specimens, identified as Pimelodusblochii Valenciennes, 1840 and collected from the lower courses of the Tapajós, Amazonas and Trombetas Rivers. The karyotypes were characterized by Giemsa conventional staining, C-banding, silver staining (Ag-NOR) and fluorescent in situ hybridization (FISH) with 5S and 18S rDNA probes. The karyotypes showed 2n=56 chromosomes in fish from the Tapajós River. In contrast, fish from the Amazonas and Trombetas Rivers had 2n=58. The nucleolus organizing regions were labeled on the short arm of an acrocentric chromosome as demonstrated by silver staining and FISH. Signals for 18S and 5S rDNA were co-localized on one chromosome pair. Our results demonstrate karyotypic divergence between Tapajós and Amazonas-Trombetas populations of P.blochii, interpreted as supporting the existence of a species complex in this taxon.

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Interspecific chromosomal divergences in the genus Characidium (Teleostei: Characiformes: Crenuchidae)

Neotropical Ichthyology ◽

10.1590/s1679-62252010000100010 ◽

2010 ◽

Vol 8 (1) ◽

pp. 77-86 ◽

Cited By ~ 15

Author(s):

José Carlos Pansonato Alves ◽

Luiz Ricardo de Souza Paiva ◽

Claudio Oliveira ◽

Fausto Foresti

Keyword(s):

Chromosome Pair ◽

Diploid Number ◽

Constitutive Heterochromatin ◽

Sex Chromosome ◽

Way Of Life ◽

Geographical Isolation ◽

Relevant Role ◽

Sex Chromosome System ◽

Morphological Differences ◽

First Time

Karyotypes of seven fish species of the genus Characidium, three of them studied for the first time, were characterized using conventional cytogenetic techniques (Giemsa staining, Ag-NOR, and C-banding). All species presented a diploid number of 2n=50, with only metacentric and submetacentric chromosomes, as observed in all Characidium species studied. In two species cells with one to three B chromosomes were observed. All species analyzed have a single NOR-bearing chromosome pair with morphological differences among them. Characidium cf. zebra shows heterochromatic blocks restricted to the pericentromeric regions of all chromosomes denoting the absence of a sex chromosome system. On the other hand, the species Characidium lanei, C. pterostictum, C. lauroi, C. oiticicai, C. schubarti, and Characidium sp., besides presenting pericentromeric heterochromatic blocks, exhibited large interstitial and/or terminal heterochromatic blocks, and a ZZ/ZW sex chromosome system. The constitutive heterochromatin seems to play a relevant role in the chromosome differentiation process of the studied species, mainly in relation to the sex chromosomes. The geographical isolation of the rivers in which the species were sampled, associated with their way of life restricted to headwaters environments, may have favored the process of fixation of different karyotypes found in each of the analyzed species.

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Contributions to the systematic of Pimelodidae (Osteichthyes, Siluriformes): basic and molecular cytogenetics on seven species of Pimelodus from three Brazilian hydrographic systems

Neotropical Ichthyology ◽

10.1590/1982-0224-20170148 ◽

2018 ◽

Vol 16 (2) ◽

Cited By ~ 2

Author(s):

Simone C. Girardi ◽

Carla S. Pavanelli ◽

Vladimir P. Margarido

Keyword(s):

18S Rdna ◽

Molecular Cytogenetics ◽

5S Rdna ◽

Neotropical Region ◽

Valid Species ◽

Rdna Sites ◽

The Family ◽

Rdna Fish ◽

Pimelodus Maculatus ◽

Cytogenetic Methods

ABSTRACT Pimelodidae harbors several species and is widely distributed throughout the Neotropical region. Pimelodus is the genus with the largest number of species, however it is a polyphyletic group. Cytogenetic analyzes of the valid species still covers less than half of them. Herein, seven Pimelodus species from three Brazilian hydrographic systems were analyzed through basic (Giemsa, AgNORs and C banding) and molecular (5S and 18S rDNA-FISH) cytogenetic methods. All species had 2n=56 chromosomes with different karyotype formulas observed among the species. AgNORs were corresponding to 18S rDNA and localized on long arm of one chromosome pair in all species. Heterochromatin distribution follows the pattern commonly verified in the family and allows to identify each one of the studied species. 5S rDNA marker was interspecifically variable in number and position of cistrons. Pimelodus ortmanni had B chromosomes varying intra and inter-individually. We performed a discussion on our own and available cytogenetic data for Pimelodidae, and the associating of them with available phylogeny enable us identifying features that distinguish subgroups within Pimelodidae, such as NORs location (terminal/long arm for species belonging to “Iheringichthys-Parapimelodus” and “Pimelodus maculatus” subclades) and location of 5S rDNA sites (pericentromeric/interstitial/ long arm for species belonging to Pimelodus group).

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Chromosomal Mapping of Repetitive DNAs in Characidium (Teleostei, Characiformes): Genomic Organization and Diversification of ZW Sex Chromosomes

Cytogenetic and Genome Research ◽

10.1159/000437165 ◽

2015 ◽

Vol 146 (2) ◽

pp. 136-143 ◽

Cited By ~ 10

Author(s):

Priscilla C. Scacchetti ◽

Ricardo Utsunomia ◽

José C. Pansonato-Alves ◽

Marcelo R. Vicari ◽

Roberto F. Artoni ◽

...

Keyword(s):

Sex Chromosomes ◽

Dna Sequences ◽

Sex Chromosome ◽

Repetitive Sequences ◽

5S Rdna ◽

Chromosome Mapping ◽

Chromosomal Mapping ◽

Specific Probe ◽

W Chromosome ◽

Sex Chromosome System

The speciose neotropical genus Characidium has proven to be a good model for cytogenetic exploration. Representatives of this genus often have a conserved diploid chromosome number; some species exhibit a highly differentiated ZZ/ZW sex chromosome system, while others do not show any sex-related chromosome heteromorphism. In this study, chromosome painting using a W-specific probe and comparative chromosome mapping of repetitive sequences, including ribosomal clusters and 4 microsatellite motifs - (CA)15, (GA)15, (CG)15, and (TTA)10 -, were performed in 6 Characidium species, 5 of which possessed a heteromorphic ZW sex chromosome system. The W-specific probe showed hybridization signals on the W chromosome of all analyzed species, indicating homology among the W chromosomes. Remarkably, a single major rDNA-bearing chromosome pair was found in all species. The 18S rDNA localized to the sex chromosomes in C. lanei, C. timbuiense and C. pterostictum, while the major rDNA localized to one autosome pair in C. vidali and C. gomesi. In contrast, the number of 5S rDNA-bearing chromosomes varied. Notably, minor ribosomal clusters were identified in the W chromosome of C. vidali. Microsatellites were widely distributed across almost all chromosomes of the karyotypes, with a greater accumulation in the subtelomeric regions. However, clear differences in the abundance of each motif were detected in each species. In addition, the Z and W chromosomes showed the differential accumulation of distinct motifs. Our results revealed variability in the distribution of repetitive DNA sequences and their possible association with sex chromosome diversification in Characidium species.

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