scholarly journals Dynamics of the hobo transposable element in transgenic lines of Drosophila melanogaster

2001 ◽  
Vol 77 (2) ◽  
pp. 135-142 ◽  
Author(s):  
V. LADEVEZE ◽  
S. AULARD ◽  
N. CHAMINADE ◽  
C. BIEMONT ◽  
G. PERIQUET ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Transposable Element ◽  
High Frequency ◽  
Chromosomal Distribution ◽  
Extensive Survey ◽  
Transgenic Lines ◽  
Insertion Sites ◽  
Selection For ◽  
Genomic Regions ◽  
The Impact

The impact of the hobo transposable element in global reorganization of the Drosophila melanogaster genome has been investigated in transgenic lines generated by injection of hobo elements into the Hikone strain, which lacked them. In the present extensive survey, the chromosomal distribution of hobo insertion sites in the line 28 was found to be homogeneous and similar for all chromosomal arms, except 3L, when compared with other transgenic lines. However, some original features were observed in this line at the genetic and chromosomal levels. Several hotspots of insertion sites were observed on the X, second and third chromosomes. Five sites with a high frequency of hobo insertions were present on the 3L arm in most individuals tested, suggesting the action of selection for hobo element in some sites. The presence of doublets or triplet was also observed, implying that hobo inserts can show local jumps or insertions in preferred regions. This local transposition occurred independently in 11 specific genomic regions in many individuals and generations. The dynamics of this phenomenon were analysed across generations. These results support the use of the hobo system as an important tool in fundamental and applied Drosophila genetics.

scholarly journals Direct determination of retrotransposon transposition rates in Drosophila melanogaster

1994 ◽  
Vol 63 (2) ◽  
pp. 139-144 ◽  
Author(s):  
Sergey V. Nuzhdin ◽  
Trudy F. C. Mackay
Keyword(s):  
Drosophila Melanogaster ◽  
Transposable Element ◽  
Inbred Line ◽  
Copy Number ◽  
Direct Determination ◽  
Hybridization Analysis ◽  
Spontaneous Mutations ◽  
Insertion Sites

SummaryRates of transposition and excision of the Drosophila melanogaster retrotransposon elements mdg3, 297, Doc, roo and copia were estimated directly, by in situ hybridization analysis of their cytological insertion sites in 31 replicates of a highly inbred line that had accumulated spontaneous mutations for approximately 160generations. Estimated transposition rates of Doc, roo and copia were, respectively, 4·2 × 10−5, 3·1 × 10−3 and 1·3 − 10−3; no transpositions of 297 nor mdg3 were observed. Rates of transposition of copia varied significantly among sublines. Excisions were only observed for roo elements, at a rate of 9·0 × 10−6 per element per generation. Copy number averaged over these element families increased 5·9 %; therefore, in these lines the magnitude of the forces opposing transposable element multiplication were weaker than transposition rates.

scholarly journals Transmission pattern of hobo transposable element in transgenic lines of Drosophila melanogaster

1998 ◽  
Vol 71 (2) ◽  
pp. 97-107 ◽  
Author(s):  
VERONIQUE LADEVEZE ◽  
IBO GALINDO ◽  
NICOLE CHAMINADE ◽  
LUIS PASCUAL ◽  
GEORGES PERIQUET ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Population Studies ◽  
Insertion Site ◽  
Molecular Analyses ◽  
Transgenic Lines ◽  
Genomic Dnas ◽  
Insertion Sites ◽  
Method Show

This study is an attempt to trace the fate of hobo elements in the genomes of E strains of Drosophila melanogaster that have been transfected with pHFL1, a plasmid containing an autonomous hobo. Such long-term population studies (over 105 generations) could be very useful for better understanding the population and genomic dynamics of transposable elements and their pattern of insertions. Molecular analyses of hobo elements in the transfected lines were performed using Southern blots of XhoI-digested genomic DNAs. The complete element was observed in all six injected lines. In two lines we observed, at generation 100, two deleted elements, which did not correspond to Th1 and Th2. The results obtained by the in situ method show that the number of hybridization sites increases in each line and prove that the hobo element may be amplified in an RM genome. The hobo activity does not seem to be systematically correlated with the number of hobo elements. After generation 85, the evolution of the hobo element's insertion site number depends on the injected line. In all lines, the total number of insertions remains quite small, between 0 and 11. Hobo elements are located on each of the chromosomal arms. We describe ‘hotspots’ – insertion sites present in all lines and in all generations. On the 3R arm, a short inversion appeared once at generation 85.

scholarly journals IR hybrid dysgenesis increases the frequency of recombination in Drosophila melanogaster

1995 ◽  
Vol 65 (3) ◽  
pp. 167-174 ◽  
Author(s):  
Marie-Christine Chaboissier ◽  
Françoise Lemeunier ◽  
Alain Bucheton
Keyword(s):  
Drosophila Melanogaster ◽  
Transposable Element ◽  
High Frequency ◽  
Germ Line ◽  
Hybrid Dysgenesis ◽  
High Rate ◽  
I Factor

SummaryThe I factor is a LINE-like transposable element responsible for the I-R system of hybrid dysgenesis in Drosophila melanogaster. Inducer strains of this species contain several I factors whereas reactive strains do not. I factors are stable in inducer strains, but transpose at high frequency in the germ-line of females, known as SF females, produced by crossing reactive females and inducer males. Various abnormalities occur in SF females, most of which result from this high rate of transposition. We report here that recombination is increased in the germ-line of these females. This is a new characteristic of the I-R system of hybrid dysgenesis that might also be associated with transposition of the I factor.

scholarly journals INVESTIGATION OF THE NATURE OF P-INDUCED MALE RECOMBINATION IN DROSOPHILA MELANOGASTER

Genetics ◽  
1985 ◽  
Vol 110 (2) ◽  
pp. 257-279
Author(s):  
Donald A R Sinclair ◽  
Thomas A Grigliatti
Keyword(s):  
Drosophila Melanogaster ◽  
Distribution Pattern ◽  
High Frequency ◽  
Radiation Treatment ◽  
Chromosomal Distribution ◽  
Mutagenic Potential ◽  
Male Recombination ◽  
Pleiotropic Mutation

ABSTRACT The present study consists of an investigation of P-induced male recombination in Drosophila melanogaster from a number of perspectives. In an initial set of experiments, male recombination induced by several different P strains was examined on both major autosomes. The ability of these P strains to evoke recombination is striking; in many cases it exceeded that of radiation treatment. Also of interest is the apparent nonrandom chromosomal distribution of P-exchange breakpoints. The data suggest that both recombinagenic capacity and distribution pattern of exchange breakpoints may be P-strain specific. In addition to these findings, we have confirmed previous indications that P-induced exchange is reasonably symmetrical and that it frequently occurs during premeiotic stages of spermatogenesis. Moreover, we have established that radiation and P background act additively with regard to the induction of male recombination. The second part of the work involved an analysis of heterochromatic vs. euchromatic recombination induced by several recombinagenically potent P strains. Results of these experiments have confirmed our earlier findings concerning the recombinagenic capacity of P strains. More importantly, it would appear that P-induced exchange in heterochromatin is rare. The induction of various kinds of mutations was also monitored in several of these experiments. The results indicate that the mutagenic potential of the P strains is substantial and of particular interest, that certain types of mutations are P-strain specific. For example, rare heterochromatic lesions were recovered exclusively in the experiment using the h12 strain, whereas a novel pleiotropic mutation occurred at a high frequency only in the T-007 experiment. Our findings are discussed within the context of a model of P-induced exchange.

scholarly journals Is hobo permissivity related to I reactivity and sensitive to chromatin compaction in Drosophila melanogaster?

2004 ◽  
Vol 84 (2) ◽  
pp. 71-79
Author(s):  
CLAUDE BAZIN ◽  
BÉATRICE DEJONGHE ◽  
DOMINIQUE HIGUET
Keyword(s):  
Drosophila Melanogaster ◽  
Transposable Element ◽  
Position Effect ◽  
Hybrid Dysgenesis ◽  
Chromatin State ◽  
Position Effect Variegation ◽  
Chromatin Compaction ◽  
Effect Variegation ◽  
The Impact ◽  
Strain Variability

In Drosophila melanogaster, the hobo transposable element is responsible for a hybrid dysgenesis syndrome. It appears in the germline of progenies from crosses between females devoid of hobo elements (E) and males bearing active hobo elements (H). In the HE system, permissivity is the ability of females to permit hobo activity in their progeny when they have been crossed with H males. Permissivity displays both intra- and inter-strain variability and decreases with the age of the females. Such characteristics are reminiscent of those for the reactivity in the IR system. The reactivity is the ability of R females (devoid of I factors) to permit activity of the I LINE retrotransposon in the F1 females resulting from crosses with I males (bearing I factors). Here we investigated permissivity properties in the HE system related to reactivity in the IR system. Previously it had been shown that reactivity increases with the number of Su(var)3-9 genes, which increases chromatin compaction near heterochromatin. Using the same lines, we show that permissivity increases with the number of Su(var)3-9 genes. To investigate the impact of chromatin compaction on permissivity we have tested the polymorphism of position-effect variegation (PEV) on the whitemottled4 locus in RE strains. Our results suggest a model of regulation in which permissivity could depend on the chromatin state and on the hobo vestigial sequences.

scholarly journals Dynamics of transposable element invasions with piRNA clusters

2018 ◽  
Author(s):  
Robert Kofler
Keyword(s):  
Drosophila Melanogaster ◽  
Equilibrium State ◽  
Transposable Element ◽  
Negative Selection ◽  
Large Scale ◽  
Real Data ◽  
Copy Numbers ◽  
Pirna Cluster ◽  
The Impact ◽  
Random Insertion

AbstractIn mammals and in invertebrates the proliferation of a newly invading transposable element (TE) is thought to be stopped by a random insertion of one member of the invading TE family into a piRNA cluster. This view is known as the trap model. Here we explore the dynamics of TE invasions under the trap model using large-scale computer simulations. We found that piRNA clusters confer a substantial benefit, effectively preventing extinction of host populations from an uncontrollable proliferation of deleterious TEs. We show that TE invasions under the trap model consists of three distinct phases: first the TE rapidly amplifies within the population, next TE proliferation is stopped by segregating cluster insertions and finally the TE is permanently inactivated by fixation of a cluster insertion. Suppression by segregating cluster insertions is unstable and bursts of TE activity may yet occur. The transpositon rate and the population size mostly influence the length of the phases but not the amount of TEs accumulating during an invasion. Solely the size of piRNA clusters was identified as a major factor influencing TE abundance. Investigating the impact of different cluster architectures we found that a single non-recombining cluster (e.g. the somatic cluster flamenco in Drosophila) is more efficient in stopping invasions than clusters distributed over several chromosomes (e.g germline cluster in Drosophila). With the somatic architecture fewer TEs accumulate during an invasion and fewer cluster insertions are required to stop the TE. The inefficiency of the germline architecture stems from recombination among cluster sites which makes it necessary that each diploid carries, on the average, four cluster insertions, such that most individuals will end up with at least one cluster insertion. Surprisingly we found that negative selection in a model with piRNA clusters can lead to a novel equilibrium state, where TE copy numbers remain stable despite only some individuals in a population carrying a cluster insertion. Finally when applying our approach to real data from Drosophila melanogaster we found that the trap model reasonably well accounts for the abundance of germline TEs but not of somatic TEs. The abundance of somatic TEs, such as gypsy, is much lower than expected.

scholarly journals High-frequency illegitimate integration of transfected DNA at preintegrated target sites in a mammalian genome.

1996 ◽  
Vol 16 (1) ◽  
pp. 10-18 ◽  
Author(s):  
R V Merrihew ◽  
K Marburger ◽  
S L Pennington ◽  
D B Roth ◽  
J H Wilson
Keyword(s):  
Cell Lines ◽  
High Frequency ◽  
Parental Cell ◽  
Cell System ◽  
Mammalian Genome ◽  
Aprt Gene ◽  
Target Sites ◽  
A Cell ◽  
Selection For ◽  
Genomic Regions

To examine the mechanisms of recombination governing the illegitimate integration of transfected DNA into a mammalian genome, we developed a cell system that selects for integration events in defined genomic regions. Cell lines with chromosomal copies of the 3' portion of the adenine phosphoribosyltransferase (APRT) gene (targets) were established. The 5' portion of the APRT gene, which has no homology to the integrated 3' portion, was then electroporated into the target cell lines, and selection for APRT gene function was applied. The reconstruction of the APRT gene was detected at frequencies ranging from less than 10(-7) to 10(-6) per electroporated cell. Twenty-seven junction sequences between the integrated 5' APRT and its chromosomal target were analyzed. They were found to be randomly distributed in a 2-kb region immediately in front of the 3' portion of the APRT gene. The junctions fell into two main classes: those with short homologies (microhomologies) and those with inserted DNA of uncertain origin. Three long inserts were shown to preexist elsewhere in the genome. Reconstructed cell lines were analyzed for rearrangements at the target site by Southern blotting; a variety of simple and complex rearrangements were detected. Similar analysis of individual clones of the parental cell lines revealed analogous types of rearrangement, indicating that the target sites are unstable. Given the high frequency of integration events at these sites, we speculate that transfected DNA may preferentially integrate at unstable mammalian loci. The results are discussed in relation to possible mechanisms of DNA integration.

scholarly journals Fitness consequences of biochemical adaptation in Drosophila melanogaster populations under simultaneous selection for faster pre-adult development and extended lifespan

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Khushboo Sharma ◽  
Mallikarjun N. Shakarad
Keyword(s):  
Drosophila Melanogaster ◽  
Adult Development ◽  
Critical Size ◽  
Adult Life ◽  
Life Time ◽  
Growth Duration ◽  
Biochemical Adaptation ◽  
Selection For ◽  
The Impact ◽  
Time Point

AbstractIn holometabolous insects like Drosophila melanogaster, critical size is an important time point during larval life, for irreversible commitment to metamorphosis. Here, we studied the impact of restricted growth duration in terms of selection for faster pre-adult development in Drosophila melanogaster populations which resulted in the evolution of reduced critical size on adult life history traits. Selection for faster pre-adult development resulted in biochemical adaptation in larval physiology with no compromise in major biomolecules at critical size time point. The flies from the selected populations seem to not only commit to metamorphosis on the attainment of critical size but also seem to channelize resources to reproduction as indicated by similar life-time fecundity of CS and NS flies from selected populations, while the Control CS flies significantly lower life-time fecundity compared to Control NS flies. The flies from selected populations seem to achieve longevity comparable to control flies despite being significantly smaller in size-thus resource constrained due to faster pre-adult development.

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