Cotransposition of a highly repetitive DNA element with flanking sequences in the genome of the midgeChironomus thummi

Hankeln, T; Schmidt, Erwin R.

doi:10.1007/bf02101149

Cited by 12 publications

(19 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…) further hints at an ongoing Cla‐element transposition, presumably via RNA intermediates that are then reverse transcribed and re‐integrated into the genome. Monomeric Cla‐elements are structurally similar to classical SINE retroelements (Hankeln & Schmidt ). However, SINEs depend on active LINEs (long interspersed nuclear elements) for their retrotransposition machinery (Wicker et al .…”

Section: Discussionmentioning

confidence: 95%

“…The third indication of ongoing activity is the presence of monomeric or dimeric Cla‐element transcripts in C. riparius , as evidenced by transcriptome data (Table , Supporting Information), northern hybridization (Hankeln & Schmidt ) and RT–PCR (Martinez‐Guitarte et al . ) further hints at an ongoing Cla‐element transposition, presumably via RNA intermediates that are then reverse transcribed and re‐integrated into the genome.…”

Section: Discussionmentioning

confidence: 95%

“…If the same negative selection pressure inferred to act on heterozygous Cla‐element insertions in the current populations applied in the past, most of the Cla‐element insertions would have been fixed as they are today and could not get lost differentially. Sequence comparisons of the Cla consensus sequence revealed high similarity to the sister species C. piger (3.7% Cla‐element divergence, Hankeln & Schmidt ) and also to the more distantly related C. luridus (Ross et al . ).…”

Section: Discussionmentioning

confidence: 99%

“…The exact mechanism of transposition of these sequences is unclear, and it is unknown whether Cla‐elements are still active. In C. piger and the more distantly related C. luridus , Cla‐element clusters are mostly restricted to centromeric regions, whereas in C. riparius, they additionally occur across most chromosomal arms (Schmidt ; Hankeln & Schmidt ; Hankeln et al . ).…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Chironomus riparius (Diptera) genome sequencing reveals the impact of minisatellite transposable elements on population divergence

et al. 2017

View full text Add to dashboard Cite

Active transposable elements (TEs) may result in divergent genomic insertion and abundance patterns among conspecific populations. Upon secondary contact, such divergent genetic backgrounds can theoretically give rise to classical Dobzhansky-Muller incompatibilities (DMI), thus contributing to the evolution of endogenous genetic barriers and eventually causing population divergence. We investigated differential TE abundance among conspecific populations of the nonbiting midge Chironomus riparius and evaluated their potential role in causing endogenous genetic incompatibilities between these populations. We focussed on a Chironomus-specific TE, the minisatellite-like Cla-element, whose activity is associated with speciation in the genus. Using a newly generated and annotated draft genome for a genomic study with five natural C. riparius populations, we found highly population-specific TE insertion patterns with many private insertions. A significant correlation of the pairwise F estimated from genomewide single-nucleotide polymorphisms (SNPs) and the F estimated from TEs is consistent with drift as the major force driving TE population differentiation. However, the significantly higher Cla-element F level due to a high proportion of differentially fixed Cla-element insertions also indicates selection against segregating (i.e. heterozygous) insertions. With reciprocal crossing experiments and fluorescent in situ hybridization of Cla-elements to polytene chromosomes, we documented phenotypic effects on female fertility and chromosomal mispairings. We propose that the inferred negative selection on heterozygous Cla-element insertions may cause endogenous genetic barriers and therefore acts as DMI among C. riparius populations. The intrinsic genomic turnover exerted by TEs may thus have a direct impact on population divergence that is operationally different from drift and local adaptation.

show abstract

Section: Discussionmentioning

confidence: 95%

Section: Discussionmentioning

confidence: 95%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Chironomus riparius (Diptera) genome sequencing reveals the impact of minisatellite transposable elements on population divergence

et al. 2017

View full text Add to dashboard Cite

show abstract

“…The reciprocal phenomenon is found in Chironomus (Schmidt et al 1982;Schmidt 1984) where satellite DNA sequences (the Cla elements) are inserted into the rDNA of C. thummi thummi but not C. thummi piger. Cla elements are possibly SINEs transposed via an RNA intermediate (Hankeln and Schmidt 1987). A different situation is shown by Anemone blanda, where a tandemly repetitive sequence family exhibits homologies with the 25S rDNA (Hagemann et al 1993).…”

Section: Discussionmentioning

confidence: 98%

Molecular structure of the rDNA intergenic spacer (IGS) in Triturus: implications for the hypervariability of rDNA loci

Lucchini

Andronico²,

Nardi

1997

Chromosoma

View full text Add to dashboard Cite

Ribosomal DNA (rDNA) variation in the species Triturus vulgaris meridionalis (Amphibia, Urodela) is remarkable because of unusually high intraspecific variability in the number and distribution of ribosomal loci in the karyotype; in addition, portions of the intergenic spacer (IGS) are clustered at chromosomal loci where they are not associated with ribosomal 18S and 28S RNA genes. These clusters are referred to as extraribosomal, and they appear to consist mostly of repetitive BamHI elements. In this paper, we report the complete nucleotide sequence of an IGS of T. v. meridionalis; this structural analysis is aimed to get insight into the molecular mechanism(s) of spreading of the ribosomal cistrons as well as its possible functional significance. We found that the IGS of T. vulgaris has a modular structure: modular repetitive elements contain sequences possibly related to the regulation of transcription of the ribosomal units. In particular, both ribosomal and extraribosomal IGS elements contain presumptive enhancers. Interestingly, the enhancer-containing region is mostly conserved between ribosomal and extraribosomal elements, while mutations accumulate in a region characterized by repetitions of a simple sequence motif, that we consider as a possible recombination hotspot. Our data suggest that extraribosomal elements most probably originated from ribosomal enhancer-containing elements able to move independently from the ribosomal unit at novel chromosomal positions, perhaps with the aid of the simple repetitive motif. We argue that a similar mechanism may lead to the spreading of complete repetition units as well, giving rise to multiple, and variable, ribosomal sites. We propose that hypervariability in the number and distribution of the rDNA loci, as seen in T. vulgaris, is a further mechanism to ensure redundancy, which seems to be an intrinsic property of rDNA biology, the occurrence of IGS elements independently clustered at separate chromosomal loci being a by-product of this mechanism.

show abstract

A new transposable element inChironomus thummi

et al. 1990

View full text Add to dashboard Cite

A 1.7 kb long transposable element called TECth1 was found in the 3' flanking region of a Chironomus thummi Balbiani ring gene. As shown by sequence comparison with a second copy, TECth1 is characterized by a perfect terminal inverted repeat of 17 bp flanked by a duplicated target site of 8 bp, four internal imperfect inverted repeats of 17 to 26 bp and terminal regions of about 0.25 kb with a high number of short direct repeats of the consensus sequence ACTTT or permutated and mutated forms such as TTTAC or ACTAT. The terminal inverted repeats and the 8 bp target site duplication are reminiscent of Drosophila P and hobo elements but no long open reading frame starting with ATG is present, suggesting that the two TECth1 copies studied represent deletion derivatives of a longer element coding for its own transposase. In situ hybridization revealed about 75 labelled sites distributed over all chromosomes with the Balbiani ring locus most strongly labelled. Fifty percent of the sites are specific for a given individual, and these variable sites are often heterozygous for the element.

show abstract

Cotransposition of a highly repetitive DNA element with flanking sequences in the genome of the midgeChironomus thummi

Cited by 12 publications

References 29 publications

Chironomus riparius (Diptera) genome sequencing reveals the impact of minisatellite transposable elements on population divergence

Chironomus riparius (Diptera) genome sequencing reveals the impact of minisatellite transposable elements on population divergence

Molecular structure of the rDNA intergenic spacer (IGS) in Triturus: implications for the hypervariability of rDNA loci

A new transposable element inChironomus thummi

Contact Info

Product

Resources

About