Geographically localised bursts of ribosomal DNA mobility in the grasshopper Podisma pedestris

Veltsos, Paris; Keller, Irene; Nichols, Richard A.

doi:10.1038/hdy.2009.32

Cited by 18 publications

(13 citation statements)

References 59 publications

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“…NOR clusters thus behave as neutral genetic markers tracking evolutionary variation in the nuclear genome among subspecies of M. musculus (see Veltsos et al, 2009). The processes regulating this variability remain, however, poorly understood.…”

Section: Resultsmentioning

confidence: 99%

“…However, these investigations often included only one or a few individuals per species, so population surveys of NOR variability using FISH remain scarce (Veltsos et al, 2009). One indication of intraspecific NOR variability stems from a study in humans in which 54.2% exhibited a polymorphism for the absence/presence of rRNA genes on the NOR-bearing chromosomes (Zavala Guillén et al, 2004).…”

Section: Consequences For Phylogenetic Reconstructionsmentioning

confidence: 99%

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Chromosomal dynamics of nucleolar organizer regions (NORs) in the house mouse: micro-evolutionary insights

2011

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Variation in the number and chromosomal location of nucleolar organizer regions (NORs) was studied in the house mouse, Mus musculus (2n¼40). From an origin in Western Asia, this species colonized the Middle East, Europe and Asia. This expansion was accompanied by diversification into five subspecies. NOR diversity was revealed by fluorescence in situ hybridization using 18S and 28S probes on specimens spanning Asia to Western Europe. The results showed that the house mouse genome possessed a large number of NOR-bearing autosomes and a surprisingly high rate of polymorphism for the presence/absence of rRNA genes on all these chromosomes. All NOR sites were adjacent to the centromere except for two that were telomeric. Subspecific differentiation established from the NOR frequency data was concordant with the overall pattern of radiation proposed from molecular studies, but highlighted several discrepancies that need to be further addressed. NOR diversity in M. musculus consisted of a large number of polymorphic NORs that were common to at least two subspecies, and a smaller number of NORs that were unique to one subspecies. The most parsimonious scenario argues in favor of a subspecific differentiation by lineage sorting of ancestral NOR polymorphisms; only the unique NORs would have appeared by interchromosomal transposition, except for the two telomeric ones that may have originated by hybridization with another species. Such a scenario provides an alternative view from the one prevailing in most systematic and phylogenetic analyses that NORs have a high transposition rate due to concerted evolution of rRNA genes.

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Section: Resultsmentioning

confidence: 99%

Section: Consequences For Phylogenetic Reconstructionsmentioning

confidence: 99%

Chromosomal dynamics of nucleolar organizer regions (NORs) in the house mouse: micro-evolutionary insights

2011

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“…An intermediate situation between types 1 and 2 rDNA distribution is found within the Gomphocerini tribe, in G. rufus , which has 5 clusters of rDNA in pericentric C-blocks. Intragenomic spread of rDNA has been shown in other grasshopper species [Bugrov et al, 2003[Bugrov et al, , 2004Cabrero and Camacho, 2008;Lopez-Leon et al, 2008;Veltsos et al, 2009], and the mobile nature of rDNA was first suggested by Schubert [1984] and Schubert and Wobus [1985] and has frequently been mentioned in the literature. Although the spread of rDNA repeats among pericentric regions from nonhomologous chromosomes may actually occur by transposition of mobile elements and the presence of transposable elements in rDNA clusters is well documented [Eickbush et al, 1997;Eickbush, 2002;Eickbush and Eickbush, 2007], the mechanisms by which this spread takes place are unknown (but see interesting hypotheses in Dubcovsky and Dvorak [1995]).…”

Section: Discussionmentioning

confidence: 99%

Chromosomal Localization of Ribosomal and Telomeric DNA Provides New Insights on the Evolution of Gomphocerinae Grasshoppers

Jetybayev

Bugrov²,

Карамышева³

et al. 2012

Cytogenet Genome Res

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Chromosome location of ribosomal DNA (rDNA) and telomeric repeats was analysed in mitotic chromosomes of 15 species of Gomphocerinae grasshoppers belonging to the tribes Arcypterini, Gomphocerini, Stenobothrini, and Chrysochraontini. Two types of rDNA distribution were found in the Gomphocerini tribe. Type 1, found in 9 species, was characterized by the presence of rDNA in the short arm of the long biarmed chromosomes 2 and 3 and, in some species, also in the X chromosome. Type 2 was found only in Aeropus sibiricus and Stauroderus scalaris and consisted in the presence of pericentromeric rDNA blocks in all chromosomes. A comparison of rDNA distribution in Gomphocerini species with 2n♂ = 23, 2n♂ = 21, and 2n♂ = 17 suggested the possible involvement of chromosome 6 in the ancestral karyotype (2n♂ = 23) in 1 of the 3 centric fusions that decreased the chromosome number in these species. In the tribe Stenobothrini, Stenobothrus eurasius carried a single rDNA cluster in the X chromosome, likewise 2 Spanish species previously analysed, but Omocestus viridulus unusually showed a single rDNA cluster in the longest autosome. Telomeric repeats were located primarily on the ends of chromosome arms. In 2 species, however, we observed the presence of interstitial clusters outside telomeric regions. The first one, Aeropus sibiricus, exhibited a polymorphic interstitial site of telomeric repeats in chromosome 6 as a consequence of a paracentric inversion. Most remarkably, Chorthippus jacobsoni showed the presence of telomeric repeats in the pericentric regions of the 3 biarmed chromosome pairs originated by centric fusion, thus suggesting that these rearrangements were not of the Robertsonian type but true centric fusion with a probable generation of dicentric chromosomes.

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“…However, how could this happen? Several surveys have suggested that rDNA (both 5S rDNA and the major ribosomal genes) frequently moves on from one location to another in the eukaryote genome (Rooney and Ward, 2005;Datson and Murray, 2006;Veltos et al, 2009;Nguyen et al, 2010), and several mechanisms have been proposed to explain this apparent mobility. Drouin and Moniz de Sá (1995) hypothesised that a 5S rDNA transposition could be produced at the DNA level mediated by extrachromosomal circular DNA or by an RNA intermediate.…”

Section: Upstream Elements Internal Regulatory Regions and Downstreamentioning

confidence: 99%

The linked units of 5S rDNA and U1 snDNA of razor shells (Mollusca: Bivalvia: Pharidae)

et al. 2011

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The linkage between 5S ribosomal DNA and other multigene families has been detected in many eukaryote lineages, but whether it provides any selective advantage remains unclear. In this work, we report the occurrence of linked units of 5S ribosomal DNA (5S rDNA) and U1 small nuclear DNA (U1 snDNA) in 10 razor shell species (Mollusca: Bivalvia: Pharidae) from four different genera. We obtained several clones containing partial or complete repeats of both multigene families in which both types of genes displayed the same orientation. We provide a comprehensive collection of razor shell 5S rDNA clones, both with linked and nonlinked organisation, and the first bivalve U1 snDNA sequences. We predicted the secondary structures and characterised the upstream and downstream conserved elements, including a region at À25 nucleotides from both 5S rDNA and U1 snDNA transcription start sites. The analysis of 5S rDNA showed that some nontranscribed spacers (NTSs) are more closely related to NTSs from other species (and genera) than to NTSs from the species they were retrieved from, suggesting birth-and-death evolution and ancestral polymorphism. Nucleotide conservation within the functional regions suggests the involvement of purifying selection, unequal crossing-overs and gene conversions. Taking into account this and other studies, we discuss the possible mechanisms by which both multigene families could have become linked in the Pharidae lineage. The reason why 5S rDNA is often found linked to other multigene families seems to be the result of stochastic processes within genomes in which its high copy number is determinant.

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Geographically localised bursts of ribosomal DNA mobility in the grasshopper Podisma pedestris

Cited by 18 publications

References 59 publications

Chromosomal dynamics of nucleolar organizer regions (NORs) in the house mouse: micro-evolutionary insights

Chromosomal dynamics of nucleolar organizer regions (NORs) in the house mouse: micro-evolutionary insights

Chromosomal Localization of Ribosomal and Telomeric DNA Provides New Insights on the Evolution of Gomphocerinae Grasshoppers

The linked units of 5S rDNA and U1 snDNA of razor shells (Mollusca: Bivalvia: Pharidae)

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