Chromosomal Diversification in Two Species of <i>Pimelodus</i> (Siluriformes: Pimelodidae): Comparative Cytogenetic Mapping of Multigene Families

Malimpensa, Geovana de Cassia; Traldi, Josiane Baccarin; Martinez, Juliana; Deon, Geize Aparecida; Azambuja, Matheus; Nogaroto, Viviane; Vicari, Marcelo Ricardo; Moreira‐Filho, Orlando

doi:10.1089/zeb.2020.1892

Cited by 9 publications

(4 citation statements)

References 80 publications

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“…In Pseudacanthicus , the U2 snDNA occurred in single sites located on morphologically similar chromosomes, indicating a similar chromosomal organization among the species analyzed here. This hypothesis is supported when we compare the distribution of these genes among the karyotypes of species from different groups, such as species of the genera Astyanax [ 50 ] and Pimelodus , another group of Siluriformes [ 51 ]. On the other hand, snDNA gene mapping has shown variations in the number of sites in other loricariids, as observed in Peckoltia species (Hypostominae, Peckoltia clade), where single and multiple U1 snDNA sites occur between different species [ 10 ].…”

Section: Discussionmentioning

confidence: 94%

Chromosomal Diversification in Pseudacanthicus Species (Loricariidae, Hypostominae) Revealed by Comparative Mapping of Repetitive Sequences

Silva

Souza

Rodrigues

et al. 2022

Animals

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Pseudacanthicus is a genus of Neotropical fish with eight valid species, in addition to numerous lineages not formally identified. It occurs along the Amazon and Tocantins River basins, in Suriname and in the Guiana shield. There are no karyotypic data in the literature for species of this genus. Here, the karyotypes of three Pseudacanthicus species (P. spinosus, P. leopardus and Pseudacanthicus sp.) were comparatively analyzed by classical cytogenetics and fluorescence in situ hybridization using 18S and 5S rDNA probes, U2 snDNA and telomeric sequences. The analyzed species presented 52 chromosomes and KF = 18 m + 34 sm. Constitutive heterochromatin occurred in blocks on a few chromosomes. The 18S rDNA occurred in a single pair; interestingly, P. leopardus presented only one locus of this sequence in its diploid genome. The 5S rDNA sequence occurred in only one pair in P. leopardus, and in multiple sites in Pseudacanthicus sp. and P. spinosus. The snDNA U2 occurred in only one pair in all analyzed species. Telomeric sequences did not show interstitial sites. Although Pseudacanthicus species share the same 2n and KF, repetitive sequence analysis revealed karyotypic diversity among these species. The occurrence of DNA double-strand breaks related to fragile sites, unequal crossing over and transpositions is proposed as the mechanism of karyotypic diversification, suggesting that the conservation of the karyotypic macrostructure is only apparent in this group of fish.

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Section: Discussionmentioning

confidence: 94%

Chromosomal Diversification in Pseudacanthicus Species (Loricariidae, Hypostominae) Revealed by Comparative Mapping of Repetitive Sequences

Silva

Souza

Rodrigues

et al. 2022

Animals

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“…Species with multiple rDNA clusters do not usually exhibit silver‐staining in all clusters (reviewed by Sumner, 2003; Vicari et al ., 2008). However, it must be assumed that if a species has only a single NOR (or single 45S rDNA gene site), then it will be transcriptionally active, as evidenced for different organisms (Dobigny et al ., 2002; Barros et al ., 2015; Falcione et al ., 2018; Cholak et al ., 2020; Malimpensa et al ., 2020).…”

Section: Introductionmentioning

confidence: 99%

Evolutionary insights into the genomic organization of major ribosomal DNA in ant chromosomes

Teixeira

Aguiar

Petitclerc

et al. 2021

Insect Molecular Biology

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The major rDNA genes are composed of tandem repeats and are part of the nucleolus organizing regions (NORs). They are highly conserved and therefore useful in understanding the evolutionary patterns of chromosomal locations. The evolutionary dynamics of the karyotype may affect the organization of rDNA genes within chromosomes. In this study, we physically mapped 18S rDNA genes in 13 Neotropical ant species from four subfamilies using fluorescence in situ hybridization. Furthermore, a survey of published rDNA cytogenetic data for 50 additional species was performed, which allowed us to detect the evolutionary patterns of these genes in ant chromosomes. Species from the Neotropical, Palearctic, and Australian regions, comprising a total of 63 species from 19 genera within six subfamilies, were analysed. Most of the species (48 out of 63) had rDNA genes restricted to a single chromosome pair in their intrachromosomal regions. The position of rDNA genes within the chromosomes appears to hinder their dispersal throughout the genome, as translocations and ectopic recombination are uncommon in intrachromosomal regions because they can generate meiotic abnormalities. Therefore, rDNA genes restricted to a single chromosome pair seem to be a plesiomorphic feature in ants, while multiple rDNA sites, observed in distinct subfamilies, may have independent origins in different genera.

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“…For instance, in the cyprinid genus Hypophthalmichthys , which is not paleotetraploid as Cyprinini, a single chromosome pair carries the U1 snDNA locus ( Sember et al 2020 ). Why the U1 locus was retained duplicated in C. auratus and why this locus was reduced in other Carassius species is not yet clear, but few other known U1 mapping studies carried out on species other than cyprinids show that the U1 locus is present in a karyotype on single chromosome pair ( Cabral-De-Mello et al 2012 ; Carvalho et al 2017 ; Malimpensa et al 2020 ) as well as on six chromosome pairs ( Silva et al 2015 ). The U2 snDNA locus was previously mapped to C. carassius and C. gibelio ( Bishani et al 2021 ).…”

Section: Discussionmentioning

confidence: 99%

Cytogenetic Analysis of the Fish Genus Carassius Indicates Divergence, Fission, and Segmental Duplication as Drivers of Tandem Repeat and Microchromosome Evolution

Fornaini,

Černohorská,

do Vale Martins

et al. 2024

Genome Biology and Evolution

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Fishes of the genus Carassius are useful experimental vertebrate models for study of evolutionary biology and cytogenetics. Carassius demonstrates diverse biological characteristics, such as variation in ploidy levels and chromosome numbers, and presence of microchromosomes. Carassius polyploids with ≥ 150 chromosomes have microchromosomes, but their origin, especially in European populations, is unknown. We used cytogenetics to study evolution of tandem repeats (U1 and U2 small nuclear DNAs and H3 histone) and microchromosomes in Carassius from the Czech Republic. We tested the hypotheses whether the number of tandem repeats was affected by polyploidization or divergence between species and what mechanism drives evolution of microchromosomes. Tandem repeats were found in tetraploid and hexaploid C. gibelio, tetraploid C. auratus and C. carassius in conserved numbers, with the exception of U1 snDNA in C. auratus. This conservation indicates reduction and/or loss in the number of copies per locus that may have occurred by divergence rather than polyploidization. To study evolution of microchromosomes, we used the whole microchromosome painting probe from hexaploid C. gibelio and hybridized it to tetraploid and hexaploid C. gibelio, tetraploid C. auratus and C. carassius. Our results revealed variation in the number of microchromosomes in hexaploids, indicating that the evolution of Carassius karyotype is governed by macrochromosome fissions followed by segmental duplication in pericentromeric areas. This is a potential mechanism responsible for the presence of microchromosomes in Carassius hexaploids. Differential efficacy of one or both of these mechanisms in different tetraploids could ensure variability in chromosome number in polyploids in general.

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Chromosomal Diversification in Two Species of Pimelodus (Siluriformes: Pimelodidae): Comparative Cytogenetic Mapping of Multigene Families

Cited by 9 publications

References 80 publications

Chromosomal Diversification in Pseudacanthicus Species (Loricariidae, Hypostominae) Revealed by Comparative Mapping of Repetitive Sequences

Chromosomal Diversification in Pseudacanthicus Species (Loricariidae, Hypostominae) Revealed by Comparative Mapping of Repetitive Sequences

Evolutionary insights into the genomic organization of major ribosomal DNA in ant chromosomes

Cytogenetic Analysis of the Fish Genus Carassius Indicates Divergence, Fission, and Segmental Duplication as Drivers of Tandem Repeat and Microchromosome Evolution

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