Major and minor U small nuclear RNAs genes characterization in a neotropical fish genome: Chromosomal remodeling and repeat units dispersion in Parodontidae

Azambuja, Matheus; Schemberger, Michelle Orane; Nogaroto, Viviane; Moreira‐Filho, Orlando; Martins, Cesar; Vicari, Marcelo Ricardo

doi:10.1016/j.gene.2022.146459

Cited by 5 publications

(1 citation statement)

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“…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 ]. Thus, although the in situ locations of these sequences may indicate stability at the chromosomal level, chromosomal and molecular diversity has been observed for this group for repetitive sequences in the genomes of different fish species [ 18 , 52 , 53 ]. Therefore, analyzing the in situ locations of other snDNA genes, as well as the molecular diversity of this gene family in the genomes of Pseudacanthicus species, may reveal important mechanisms of chromosomal diversification involving this group of repetitive sequences in this group of fish.…”

Section: Discussionmentioning

confidence: 99%

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: 99%