Fragile sites, dysfunctional telomere and chromosome fusions: What is 5S rDNA role?

Barros, Alain Victor de; Wolski, Michele Andressa Vier; Nogaroto, Viviane; Almeida, Mara Cristina de; Moreira‐Filho, Orlando; Vicari, Marcelo Ricardo

doi:10.1016/j.gene.2017.01.013

Cited by 62 publications

(78 citation statements)

References 66 publications

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“…The p-arm of chromosome 8 contains a dense cluster of rDNA repeats (Brenna-Hansen et al, 2012;Lien et al, 2016) and repeated elements of rDNA have been associated with chromosomal fusions and fissions in a wide variety of species (e.g. Barros et al, 2017;Cazaux, Catalan, Veyrunes, Douzery, & Britton-Davidian, 2011;Huang, Ma, Yang, Fei, & Li, 2008;Stahl et al, 1983) suggesting they play an important role in chromosomal rearrangements and thus may explain the occurrence of the fusion we have observed. Ultimately long-read sequencing data will be necessary to verify the architecture of this chromosomal rearrangement.…”

Section: Chromosomal Rearrangement Polymorphism: a Possible Role In Lmentioning

confidence: 64%

Chromosomal fusion and life history-associated genomic variation contribute to within-river local adaptation of Atlantic salmon

Wellband

Mérot

Linnansaari

et al. 2018

Preprint

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Chromosomal inversions have been implicated in facilitating adaptation in the face of high levels of gene flow, but whether chromosomal fusions also have similar potential remains poorly understood. Atlantic salmon are usually characterized by population structure at multiple spatial scales; however, this is not the case for tributaries of the Miramichi River in North America. To resolve genetic relationships between populations in this system and the potential for known chromosomal fusions to contribute to adaptation we genotyped 728 juvenile salmon using a 50K SNP array. Consistent with previous work, we report extremely weak overall population structuring (Global FST = 0.004) and failed to support hierarchical structure between the river's two main branches. We provide the first genomic characterization of a previously described polymorphic fusion between chromosomes 8 and 29. Fusion genomic characteristics included high LD, reduced heterozygosity in the fused homokaryotes, and strong divergence between the fused and the unfused rearrangement. Population structure based on fusion karyotype was five times stronger than neutral variation (FST = 0.019) and the frequency of the fusion was associated with summer precipitation supporting a hypothesis that this rearrangement may contribute local adaptation despite weak neutral differentiation. Additionally, both outlier variation among populations and a polygenic framework for characterizing adaptive variation in relation to climate identified a 250 Kb region of chromosome 9, including the gene six6 that has previously been linked to age-at-maturity and run-timing for this species. Overall our results indicate that adaptive processes, independent of major river branching, are more important than neutral processes for structuring these populations. Conservation and management of species benefit from an understanding of fine-scale demographic and evolutionary processes, which aid in delimitating appropriate population-scale

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Section: Chromosomal Rearrangement Polymorphism: a Possible Role In Lmentioning

confidence: 64%

Chromosomal fusion and life history-associated genomic variation contribute to within-river local adaptation of Atlantic salmon

Wellband

Mérot

Linnansaari

et al. 2018

Preprint

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“…According to Drouin (2000), the presence of TEs can be responsible for rRNA gene movements, and this process can be displayed by the cytogenetic analysis performed here and in previous studies. Moreover, it has been stated that a double strand break within the 5S array, followed by a non-homologous recombination repair mechanism during prophase, are events that lead to share 5S sequences among chromosomes (Barros et al, 2017;Glugoski et al, 2018).…”

Section: Discussionmentioning

confidence: 99%

Evolutionary Dynamics of Multigene Families in Triportheus (Characiformes, Triportheidae): A Transposon Mediated Mechanism?

et al. 2020

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Triportheus (Characiformes, Triportheidae) is a freshwater fish genus with 18 valid species. These fishes are widely distributed in the major river drainages of South America, having commercial importance in the fishing market, mainly in the Amazon basin. This genus has diverged recently in a complex process of speciation carried out in different river basins. The use of repetitive sequences is suitable to trace the genomic reorganizations occured along the speciation process. In this work, the 5S rDNA multigene family has been characterized at molecular and phylogenetic level. The results showed that other multigene family has been found within the non-transcribed spacer (NTS): the U1 snRNA gene. Double-FISH with 5S and U1 probes were also performed, confirming the close linkage between these two multigene families. Moreover, evidences of different transposable elements (TE) were detected within the spacer, thus suggesting a transposon-mediated mechanism of 5S-U1 evolutionary pathway in this genus. Phylogenetic analysis demonstrated a species-specific grouping, except for Triportheus pantanensis, Triportheus aff. rotundatus and Triportheus trifurcatus. The evolutionary model of the 5S rDNA in Triportheus species has been discussed. In addition, the results suggest new clues for the speciation and evolutionary trend in these species, which could be suitable to use in other Characiformes species.

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“…The location of (TTAGGG) n sites only in telomeric regions indicated the complete lack or a small number of chromosomal rearrangements of translocation/fusion types. However, the possibility of loss of this sequence after such rearrangements cannot be ruled out [Nanda et al, 1995;Barros et al, 2017].…”

Section: Discussionmentioning

confidence: 99%

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

Malimpensa

Traldi²,

Toyama³

et al. 2018

Cytogenet Genome Res

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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.

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Fragile sites, dysfunctional telomere and chromosome fusions: What is 5S rDNA role?

Cited by 62 publications

References 66 publications

Chromosomal fusion and life history-associated genomic variation contribute to within-river local adaptation of Atlantic salmon

Chromosomal fusion and life history-associated genomic variation contribute to within-river local adaptation of Atlantic salmon

Evolutionary Dynamics of Multigene Families in Triportheus (Characiformes, Triportheidae): A Transposon Mediated Mechanism?

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

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