scholarly journals Telomeric TART elements target the piRNA machinery in Drosophila

PLoS Biology ◽  
2020 ◽  
Vol 18 (12) ◽  
pp. e3000689
Author(s):  
Christopher E. Ellison ◽  
Meenakshi S. Kagda ◽  
Weihuan Cao
Keyword(s):  
Drosophila Melanogaster ◽  
Transposable Elements ◽  
Related Species ◽  
Nuclear Export ◽  
Small Rnas ◽  
Critical Role ◽  
Closely Related Species ◽  
Factor Gene ◽  
Antagonistic Coevolution ◽  
Copy Numbers

Coevolution between transposable elements (TEs) and their hosts can be antagonistic, where TEs evolve to avoid silencing and the host responds by reestablishing TE suppression, or mutualistic, where TEs are co-opted to benefit their host. The TART-A TE functions as an important component of Drosophila telomeres but has also reportedly inserted into the Drosophila melanogaster nuclear export factor gene nxf2. We find that, rather than inserting into nxf2, TART-A has actually captured a portion of nxf2 sequence. We show that TART-A produces abundant Piwi-interacting small RNAs (piRNAs), some of which are antisense to the nxf2 transcript, and that the TART-like region of nxf2 is evolving rapidly. Furthermore, in D. melanogaster, TART-A is present at higher copy numbers, and nxf2 shows reduced expression, compared to the closely related species Drosophila simulans. We propose that capturing nxf2 sequence allowed TART-A to target the nxf2 gene for piRNA-mediated repression and that these 2 elements are engaged in antagonistic coevolution despite the fact that TART-A is serving a critical role for its host genome.

scholarly journals The Drosophila TART transposon manipulates the piRNA pathway as a counter-defense strategy to limit host silencing

2020 ◽  
Author(s):  
Christopher E. Ellison ◽  
Meenakshi S. Kagda ◽  
Weihuan Cao
Keyword(s):  
Transposable Elements ◽  
Nuclear Export ◽  
Critical Role ◽  
Host Genome ◽  
Factor Gene ◽  
Defense Strategy ◽  
Pirna Pathway

AbstractCo-evolution between transposable elements (TEs) and their hosts can be antagonistic, where TEs evolve to avoid silencing and the host responds by reestablishing TE suppression, or mutualistic, where TEs are co-opted to benefit their host. The TART-A TE functions as an important component of Drosophila telomeres, but has also reportedly inserted into the D. melanogaster nuclear export factor gene nxf2. We find that, rather than inserting into nxf2, TART-A has actually captured a portion of nxf2 sequence. We show that Nxf2 is involved in suppressing TART-A activity via the piRNA pathway and that TART-A produces abundant piRNAs, some of which are antisense to the nxf2 transcript. We propose that capturing nxf2 sequence allowed TART-A to target the nxf2 gene for piRNA-mediated repression and that these two elements are engaged in antagonistic co-evolution despite the fact that TART-A is serving a critical role for its host genome.

Locomotion is not influenced by denticle number in larvae of the fruit fly Drosophila melanogaster

2005 ◽  
Vol 83 (2) ◽  
pp. 368-371 ◽  
Author(s):  
Mark J Fitzpatrick ◽  
Evelyn Szewczyk
Keyword(s):  
Drosophila Melanogaster ◽  
Related Species ◽  
Natural Variation ◽  
Fruit Fly ◽  
Fruit Flies ◽  
Negative Effects ◽  
Closely Related Species ◽  
Locomotory Performance ◽  
Locomotion Speed

Denticles are small projections on the underside of larval fruit flies that are used to grip the substrate while crawling. Previous studies have shown that (i) there is natural variation in denticle number and pattern between Drosophila melanogaster (Meigen, 1830) and several closely related species and (ii) mutations affecting denticle morphology have negative effects on locomotory performance. We hypothesized that there would be a correlation between denticle number and locomotory performance within populations of D. melanogaster. Despite finding considerable variation in denticle number, we found no correlation between denticle number and three measurements of larval locomotion: speed, acceleration, and absolute turning rate.

scholarly journals Transposable Elements and the Evolution of Insects

2021 ◽  
Vol 66 (1) ◽  
pp. 355-372
Author(s):  
Clément Gilbert ◽  
Jean Peccoud ◽  
Richard Cordaux
Keyword(s):  
Transposable Elements ◽  
Related Species ◽  
Horizontal Transfer ◽  
Population Genomics ◽  
Antiviral Immunity ◽  
Closely Related Species ◽  
Phylogenetic Relatedness ◽  
Functional Studies ◽  
Insect Symbionts

Insects are major contributors to our understanding of the interaction between transposable elements (TEs) and their hosts, owing to seminal discoveries, as well as to the growing number of sequenced insect genomes and population genomics and functional studies. Insect TE landscapes are highly variable both within and across insect orders, although phylogenetic relatedness appears to correlate with similarity in insect TE content. This correlation is unlikely to be solely due to inheritance of TEs from shared ancestors and may partly reflect preferential horizontal transfer of TEs between closely related species. The influence of insect traits on TE landscapes, however, remains unclear. Recent findings indicate that, in addition to being involved in insect adaptations and aging, TEs are seemingly at the cornerstone of insect antiviral immunity. Thus, TEs are emerging as essential insect symbionts that may have deleterious or beneficial consequences on their hosts, depending on context.

scholarly journals The distribution of transposable elements within and between chromosomes in a population of Drosophila melanogaster. I. Element frequencies and distribution

1992 ◽  
Vol 60 (2) ◽  
pp. 103-114 ◽  
Author(s):  
Brian Charlesworth ◽  
Angela Lapid ◽  
Darlene Canada
Keyword(s):  
Population Dynamics ◽  
Drosophila Melanogaster ◽  
Linkage Disequilibrium ◽  
Transposable Elements ◽  
Copy Number ◽  
Polytene Chromosomes ◽  
Chromosome Band ◽  
High Frequencies ◽  
Copy Numbers

SummaryData were collected on the distribution of nine families of transposable elements among second and third chromosomes isolated from a natural population of Drosophila melanogaster, by means of in situ hybridization of element probes to polytene chromosomes. It was found that the copy numbers per chromosome in the distal sections of the chromosome arms followed a Poisson distribution. Elements appeared to be distributed randomly along the distal sections of the chromosome arms. There was no evidence for linkage disequilibrium in the distal sections of the chromosomes, but some significant disequilibrium was detected in proximal regions. There were many significant correlations between different element families with respect to the identity of the sites that were occupied in the sample. There were also significant correlations between families with respect to sites at which elements achieved relatively high frequencies. Element frequencies per chromosome band were generally low in the distal sections, but were higher proximally. These results are discussed in the light of models of the population dynamics of transposable elements. It is concluded that they provide strong evidence for the operation of a force or forces opposing transpositional increase in copy number. The data suggest that the rate of transposition perelement per generation is of the order of 10−4, for the elements included in this study.

scholarly journals Lack of underdominance in a naturally occurring pericentric inversion in Drosophila melanogaster and its implications for chromosome evolution.

Genetics ◽  
1991 ◽  
Vol 129 (3) ◽  
pp. 791-802
Author(s):  
J A Coyne ◽  
S Aulard ◽  
A Berry
Keyword(s):  
Drosophila Melanogaster ◽  
Natural Selection ◽  
Genetic Drift ◽  
Related Species ◽  
Pericentric Inversion ◽  
Chromosome Evolution ◽  
Natural Populations ◽  
Crossing Over ◽  
Closely Related Species ◽  
Naturally Occurring

Abstract In(2LR)PL is a large pericentric inversion polymorphic in populations of Drosophila melanogaster on two Indian Ocean islands. This polymorphism is puzzling: because crossing over in female heterokaryotypes produces inviable zygotes, such inversions are thought to be underdominant and should be quickly eliminated from populations. The observed fixation for such inversions among related species has led to the idea that genetic drift can cause chromosome evolution in opposition to natural selection. We found, however, that In(2LR)PL is not underdominant for fertility, as heterokaryotypic females produce perfectly viable eggs. Genetic analysis shows that the lack of underdominance results from the nearly complete absence of crossing over in the inverted region. This phenomenon is probably caused by mechanical and not genetic factors, because crossing over is not suppressed in In(2LR)PL homokaryotypes. Our observations do not support the idea that the fixation of pericentric inversions among closely related species implies the action of genetic drift overcoming strong natural selection in very small populations. If chromosome arrangements vary in their underdominance, it is those with the least disadvantage as heterozygotes, like In(2LR)PL, that will be polymorphic or fixed in natural populations.

scholarly journals The Loci of Behavioral Evolution: Evidence That Fas2 and tilB Underlie Differences in Pupation Site Choice Behavior between Drosophila melanogaster and D. simulans

2019 ◽  
Vol 37 (3) ◽  
pp. 864-880
Author(s):  
Alison Pischedda ◽  
Michael P Shahandeh ◽  
Thomas L Turner
Keyword(s):  
Drosophila Melanogaster ◽  
X Chromosome ◽  
Related Species ◽  
Choice Behavior ◽  
Genetic Basis ◽  
Association Studies ◽  
Single Gene ◽  
Closely Related Species ◽  
Environmentally Sensitive ◽  
Pupation Site

Abstract The behaviors of closely related species can be remarkably different, and these differences have important ecological and evolutionary consequences. Although the recent boom in genotype–phenotype studies has led to a greater understanding of the genetic architecture and evolution of a variety of traits, studies identifying the genetic basis of behaviors are, comparatively, still lacking. This is likely because they are complex and environmentally sensitive phenotypes, making them difficult to measure reliably for association studies. The Drosophila species complex holds promise for addressing these challenges, as the behaviors of closely related species can be readily assayed in a common environment. Here, we investigate the genetic basis of an evolved behavioral difference, pupation site choice, between Drosophila melanogaster and D. simulans. In this study, we demonstrate a significant contribution of the X chromosome to the difference in pupation site choice behavior between these species. Using a panel of X-chromosome deficiencies, we screened the majority of the X chromosome for causal loci and identified two regions associated with this X-effect. We then collect gene disruption and RNAi data supporting a single gene that affects pupation behavior within each region: Fas2 and tilB. Finally, we show that differences in tilB expression correlate with the differences in pupation site choice behavior between species. This evidence associating two genes with differences in a complex, environmentally sensitive behavior represents the first step toward a functional and evolutionary understanding of this behavioral divergence.

scholarly journals Comparative sequence analysis of a gene-dense region among closely related species of Drosophila melanogaster

2004 ◽  
Vol 79 (6) ◽  
pp. 351-359 ◽  
Author(s):  
Yoshihiro Kawahara ◽  
Takashi Matsuo ◽  
Masafumi Nozawa ◽  
Tadasu Shin-I ◽  
Yuji Kohara ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Sequence Analysis ◽  
Related Species ◽  
Comparative Sequence Analysis ◽  
Dense Region ◽  
Closely Related Species ◽  
Comparative Sequence

scholarly journals Transposable element dynamics are consistent across the Drosophila phylogeny, despite drastically differing content

2019 ◽  
Author(s):  
Tom Hill
Keyword(s):  
Drosophila Melanogaster ◽  
Related Species ◽  
Evolutionary Dynamics ◽  
Common Ancestor ◽  
Low Frequency ◽  
Fitness Costs ◽  
Closely Related Species ◽  
Drosophila Phylogeny ◽  
Turn Over ◽  
Insertion Frequency

AbstractBackgroundThe evolutionary dynamics of transposable elements (TEs) vary across the tree of life and even between closely related species with similar ecologies. In Drosophila, most of the focus on TE dynamics has been completed in Drosophila melanogaster and the overall pattern indicates that TEs show an excess of low frequency insertions, consistent with their frequent turn over and high fitness cost in the genome. Outside of D. melanogaster, insertions in the species Drosophila algonquin, suggests that this situation may not be universal, even within Drosophila. Here we test whether the pattern observed in D. melanogaster is similar across five Drosophila species that share a common ancestor more than fifty million years ago.ResultsFor the most part, TE family and order insertion frequency patterns are broadly conserved between species, supporting the idea that TEs have invaded species recently, are mostly costly and dynamics are conserved in orthologous regions of the host genomeConclusionsMost TEs retain similar activities and fitness costs across the Drosophila phylogeny, suggesting little evidence of drift in the dynamics of TEs across the phylogeny, and that most TEs have invaded species recently.

scholarly journals Quantitative analysis of mitochondrial DNAs in macaque embryos reprogrammed by rabbit oocytes

Reproduction ◽  
2004 ◽  
Vol 127 (2) ◽  
pp. 201-205 ◽  
Author(s):  
Cai-Xia Yang ◽  
Zhao-Hui Kou ◽  
Kai Wang ◽  
Yan Jiang ◽  
Wen-Wei Mao ◽  
...  
Keyword(s):  
Related Species ◽  
Nuclear Transfer ◽  
Blastocyst Stage ◽  
Cell Nuclei ◽  
Cell Stage ◽  
Closely Related Species ◽  
Copy Numbers ◽  
Mitochondrial Dnas ◽  
Morula Stage ◽  
Pcr Method

In cloned animals where somatic cell nuclei and oocytes are from the same or closely related species, the mitochondrial DNA (mtDNA) of the oocyte is dominantly inherited. However, in nuclear transfer (NT) embryos where nuclear donor and oocyte are from two distantly related species, the distribution of the mtDNA species is not known. Here we determined the levels of macaque and rabbit mtDNAs in macaque embryos reprogrammed by rabbit oocytes. Quantification using a real-time PCR method showed that both macaque and rabbit mtDNAs coexist in NT embryos at all preimplantation stages, with maternal mtDNA being dominant. Single NT embryos at the 1-cell stage immediately after fusion contained 2.6 × 104 copies of macaque mtDNA and 1.3 × 106 copies of rabbit mtDNA. Copy numbers of both mtDNA species did not change significantly from the 1-cell to the morula stages. In the single blastocyst, however, the number of rabbit mtDNA increased dramatically while macaque mtDNA decreased. The ratio of nuclear donor mtDNA to oocyte mtDNA dropped sharply from 2% at the 1-cell stage to 0.011% at the blastocyst stage. These results suggest that maternal mtDNA replicates after the morula stage.

scholarly journals Dynamics of transposable elements in recently diverged fungal pathogens: lineage-specific transposable element content and efficiency of genome defenses

2021 ◽  
Vol 11 (4) ◽  
Author(s):  
Cécile Lorrain ◽  
Alice Feurtey ◽  
Mareike Möller ◽  
Janine Haueisen ◽  
Eva Stukenbrock
Keyword(s):  
Transposable Elements ◽  
Related Species ◽  
Fungal Pathogens ◽  
Plant Pathogens ◽  
De Novo ◽  
Zymoseptoria Tritici ◽  
Closely Related Species ◽  
Fungal Plant Pathogens ◽  
Wide Range ◽  
The Impact

Abstract Transposable elements (TEs) impact genome plasticity, architecture, and evolution in fungal plant pathogens. The wide range of TE content observed in fungal genomes reflects diverse efficacy of host-genome defense mechanisms that can counter-balance TE expansion and spread. Closely related species can harbor drastically different TE repertoires. The evolution of fungal effectors, which are crucial determinants of pathogenicity, has been linked to the activity of TEs in pathogen genomes. Here, we describe how TEs have shaped genome evolution of the fungal wheat pathogen Zymoseptoria tritici and four closely related species. We compared de novo TE annotations and repeat-induced point mutation signatures in 26 genomes from the Zymoseptoria species-complex. Then, we assessed the relative insertion ages of TEs using a comparative genomics approach. Finally, we explored the impact of TE insertions on genome architecture and plasticity. The 26 genomes of Zymoseptoria species reflect different TE dynamics with a majority of recent insertions. TEs associate with accessory genome compartments, with chromosomal rearrangements, with gene presence/absence variation, and with effectors in all Zymoseptoria species. We find that the extent of RIP-like signatures varies among Z. tritici genomes compared to genomes of the sister species. The detection of a reduction of RIP-like signatures and TE recent insertions in Z. tritici reflects ongoing but still moderate TE mobility.

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