scholarly journals Properties of transgenic strains of Drosophila melanogaster containing I transposable elements from Drosophila teissieri

1993 ◽  
Vol 61 (2) ◽  
pp. 81-90 ◽  
Author(s):  
Chantal Vaury ◽  
Alain Pélisson ◽  
Pierre Abad ◽  
Alain Bucheton
Keyword(s):  
Drosophila Melanogaster ◽  
Transposable Elements ◽  
Reverse Transcription ◽  
Copy Number ◽  
Hybrid Dysgenesis ◽  
P Element ◽  
I Factor ◽  
Transgenic Strains ◽  
Drosophila Teissieri

SummaryI factors are transposable elements of Drosophila melanogaster similar to mammalian LINEs, that transpose by reverse transcription of an RNA intermediate and are responsible for the I–R system of hybrid dysgenesis. There are two categories of strains in this species: inducer, that contain about 15 I elements at the various sites on chromosomal arms, and reactive, that lack active I factors. I elements occur in various Drosophila species. Potentially functional I factors from Drosophila teissieri can transpose when introduced by P-element-mediated transformation in a reactive strain of Drosophila melanogaster. We have studied the properties of Drosophila melanogaster strains into which such an I factor from Drosophila teissieri, named Itei, was introduced. Typical hybrid dysgenesis is produced when males carrying Itei are crossed with reactive females. However, more than one copy of the element seems necessary to produce dysgenic traits, whereas only one I factor of Drosophila melanogaster seems to be sufficient. The copy number of Itei in transformed lines maintained by endogamous crosses increases rapidly and stabilizes at values similar to those observed in inducer strains. As Drosophila teissieri contains much fewer copies than the Drosophila melanogaster strains, this suggests that the copy number of I elements is not simply regulated by sequences present in the element itself.

scholarly journals Temporal stability of P–M cytotype polymorphism in a natural population of Drosophila melanogaster

1987 ◽  
Vol 50 (2) ◽  
pp. 99-103 ◽  
Author(s):  
Hassan Izaabel ◽  
Stephane Ronsseray ◽  
Dominique Anxolabéhère
Keyword(s):  
Drosophila Melanogaster ◽  
Transposable Elements ◽  
Natural Population ◽  
North Africa ◽  
Temporal Stability ◽  
Genetic Load ◽  
Hybrid Dysgenesis ◽  
P Element ◽  
High Rate ◽  
Genetic Abnormalities

SummaryThe P–M system of hybrid dysgenesis in Drosophila melanogaster is a syndrome of genetic abnormalities which appears in the progeny of crosses between strains different with regard to their possession of ‘P’ transposable elements. Cytotype is an extrachromosomal property which regulates the mobility of the P element. We report here data showing that a cytotype polymorphism previously observed in a natural population from North-Africa is stable over a period of 5 years. A potentially high rate of mutation is associated with this cytotype polymorphism. Explanations of the appearance of a cytotype polymorphism are proposed and the consequences for the genetic load induced by transposable elements are discussed.

Hybrid dysgenesis in Drosophila melanogaster: the elimination of P elements through repeated backcrossing to an M-type strain

Genome ◽  
1987 ◽  
Vol 29 (1) ◽  
pp. 195-200 ◽  
Author(s):  
Allen G. Good ◽  
Donal A. Hickey
Keyword(s):  
Drosophila Melanogaster ◽  
Dna Hybridization ◽  
Copy Number ◽  
Natural Populations ◽  
Hybrid Dysgenesis ◽  
P Element ◽  
P Elements ◽  
Element Activity ◽  
Equivalent Reduction ◽  
Replicative Transposition

The rapid increase in the frequency of P elements in natural populations of Drosophila melanogaster has led to the suggestion that these elements can spread in nature through replicative transposition. In an attempt to model the introduction of a small number of P flies into an M population we backcrossed P flies and their offspring to M flies. Two components of dysgenesis, P element activity and P element copy number (measured by DNA hybridization), were monitored each generation. In these experiments P elements were not capable of spreading rapidly enough to maintain 30–50 copies per fly and were rapidly lost from the population. We also found that the reduction in a fly's ability to induce gonadal dysgenesis was matched by an equivalent reduction in P element copy number as measured by DNA hybridization. These results are discussed in terms of the conventional mechanisms of selection or segregation; the conclusion is that there are conditions under which P elements can be lost from a population. Key words: hybrid dysgenesis, P element, transposable elements, Drosophila.

scholarly journals Paternally Inherited P-Element Copy Number Affects the Magnitude of Hybrid Dysgenesis in Drosophila simulans and D. melanogaster

2020 ◽  
Vol 12 (6) ◽  
pp. 808-826 ◽  
Author(s):  
Antonio Serrato-Capuchina ◽  
Jeremy Wang ◽  
Eric Earley ◽  
David Peede ◽  
Kristin Isbell ◽  
...  
Keyword(s):  
Transposable Elements ◽  
Copy Number ◽  
Drosophila Species ◽  
Hybrid Dysgenesis ◽  
P Element ◽  
Isofemale Lines ◽  
Paternal Genome ◽  
P Elements ◽  
Long Read ◽  
Species Specific

Abstract Transposable elements (TEs) are repetitive regions of DNA that are able to self-replicate and reinsert themselves throughout host genomes. Since the discovery of TEs, a prevalent question has been whether increasing TE copy number has an effect on the fitness of their hosts. P-elements (PEs) in Drosophila are a well-studied TE that has strong phenotypic effects. When a female without PEs (M) is crossed to a male with them (P), the resulting females are often sterile, a phenomenon called hybrid dysgenesis (HD). Here, we used short- and long-read sequencing to infer the number of PEs in the genomes of dozens of isofemale lines from two Drosophila species and measured whether the magnitude of HD was correlated with the number of PEs in the paternal genome. Consistent with previous reports, we find evidence for a positive correlation between the paternal PE copy number and the magnitude of HD in progeny from ♀M × ♂ P crosses for both species. Other crosses are not affected by the number of PE copies. We also find that the correlation between the strength of HD and PE copy number differs between species, which suggests that there are genetic differences that might make some genomes more resilient to the potentially deleterious effects of TEs. Our results suggest that PE copy number interacts with other factors in the genome and the environment to cause HD and that the importance of these interactions is species specific.

Artificial and Epigenetic Regulation of the I Factor, a Nonviral Retrotransposon of Drosophila melanogaster

Genetics ◽  
2000 ◽  
Vol 156 (4) ◽  
pp. 1867-1878 ◽  
Author(s):  
Emmanuel Gauthier ◽  
Christophe Tatout ◽  
Hubert Pinon
Keyword(s):  
Drosophila Melanogaster ◽  
Maternal Effect ◽  
Copy Number ◽  
Hybrid Dysgenesis ◽  
Female Sterility ◽  
Paternal Effects ◽  
Transgene Copy Number ◽  
Paternal Effect ◽  
Two Generations ◽  
I Factor

Abstract The I factor (IF) is a LINE-like transposable element from Drosophila melanogaster. IF is silenced in most strains, but under special circumstances its transposition can be induced and correlates with the appearance of a syndrome of female sterility called hybrid dysgenesis. To elucidate the relationship between IF expression and female sterility, different transgenic antisense and/or sense RNAs homologous to the IF ORF1 have been expressed. Increasing the transgene copy number decreases both the expression of an IF-lacZ fusion and the intensity of the female sterile phenotype, demonstrating that IF expression is correlated with sterility. Some transgenes, however, exert their repressive abilities not only through a copy number-dependent zygotic effect, but also through additional maternal and paternal effects that may be induced at the DNA and/or RNA level. Properties of the maternal effect have been detailed: (1) it represses hybrid dysgenesis more efficiently than does the paternal effect; (2) its efficacy increases with both the transgene copy number and the aging of sterile females; (3) it accumulates slowly over generations after the transgene has been established; and (4) it is maintained for at least two generations after transgene removal. Conversely, the paternal effect increases only with female aging. The last two properties of the maternal effect and the genuine existence of a paternal effect argue for the occurrence, in the IF regulation pathway, of a cellular memory transmitted through mitosis, as well as through male and female meiosis, and akin to epigenetic phenomena.

scholarly journals Amplification of KP elements associated with the repression of hybrid dysgenesis in Drosophila melanogaster.

Genetics ◽  
1988 ◽  
Vol 120 (4) ◽  
pp. 1003-1013
Author(s):  
M S Jackson ◽  
D M Black ◽  
G A Dover
Keyword(s):  
Drosophila Melanogaster ◽  
Copy Number ◽  
Natural Populations ◽  
Selective Advantage ◽  
Complex Interaction ◽  
Hybrid Dysgenesis ◽  
P Element ◽  
Deletion Derivative ◽  
P Elements ◽  
The Way

Abstract Mobile P elements in Drosophila melanogaster cause hybrid dysgenesis if their mobility is not repressed. One type of repression, termed P cytotype, is a complex interaction between chromosomes carrying P elements and cytoplasm and is transmitted through the cytoplasm only of females. Another type of repression is found in worldwide M' strains that contain approximately 30 copies per individual of one particular P element deletion-derivative termed the KP element. This repression is transmitted equally through both sexes. In the present study we show that biparentally transmitted repression increases in magnitude together with a rapid increase in KP copy-number in genotypes starting with one or a few KP elements and no other deletion-derivatives. Such correlated increases in repression and KP number per genome occur only in the presence of complete P elements, supporting the interpretation that they are probably a consequence of the selective advantage enjoyed by flies carrying the highest numbers of KP elements. Analysis of Q strains also reveals the presence of qualitative differences in the way the repression of dysgenesis is transmitted. In general, Q strains not containing KP elements have the P cytotype mode of repression, whereas Q strains with KP elements transmit repression through both sexes. This difference among Q strains further supports the existence of at least two types of repression of P-induced hybrid dysgenesis in natural populations of D. melanogaster.

scholarly journals Detection of P element transcripts in embryos of Drosophila melanogaster and D. willistoni

2009 ◽  
Vol 81 (4) ◽  
pp. 679-689 ◽  
Author(s):  
Monica L. Blauth ◽  
Rafaela V. Bruno ◽  
Eliana Abdelhay ◽  
Elgion L.S. Loreto ◽  
Vera L.S. Valente
Keyword(s):  
Drosophila Melanogaster ◽  
Transposable Elements ◽  
Host Species ◽  
Horizontal Transfer ◽  
Hybrid Dysgenesis ◽  
P Element ◽  
Antisense Transcripts ◽  
P Elements ◽  
Drosophila Willistoni ◽  
Original Host

The P element is one of the most thoroughly studied transposable elements (TE). Its mobilization causes the hybrid dysgenesis that was first described in Drosophila melanogaster. While studies of the P element have mainly been done in D. melanogaster, it is believed that Drosophila willistoni was the original host species of this TE and that P was transposed to the D. melanogaster genome by horizontal transfer. Our study sought to compare the transcriptional behavior of the P element in embryos of D. melanogaster, which is a recent host, with embryos of two strains of D. willistoni, a species that has contained the P element for a longer time. In both species, potential transcripts of transposase, the enzyme responsible for the TE mobilization, were detected, as were transcripts of the 66-kDa repressor, truncated and antisense sequences, which can have the ability to prevent TEs mobilization. The truncated transcripts reveal the truncated P elements present in the genome strains and whose number seems to be related to the invasion time of the genome by the TE. No qualitative differences in antisense transcripts were observed among the strains, even in the D. willistoni strain with the highest frequency of heterochromatic P elements.

scholarly journals A particular P-element insertion is correlated to the P-induced hybrid dysgenesis repression in Drosophila melanogaster

1992 ◽  
Vol 60 (1) ◽  
pp. 15-24 ◽  
Author(s):  
Dominique Higuet ◽  
Dominique Anxolabéhére ◽  
Danielle Nouaud
Keyword(s):  
Drosophila Melanogaster ◽  
Promoter Activity ◽  
Hybrid Dysgenesis ◽  
P Element ◽  
P Elements ◽  
Element Insertion ◽  
Element Number

SummaryTransposable P elements in Drosophila melanogaster cause hybrid dysgenesis if their mobility is not repressed. The ability to regulate the dysgenic activity of the P elements depends on several mechanisms, one of which hypothesized that a particular deleted P element (the KP element) results in a non-susceptibility which is biparentally transmitted. In this study totally nonsusceptible lines, and susceptible lines containing exclusively KP elements (IINS2 line and IIS2 line) were isolated from a M' strain. We show that non-susceptibility is correlated with a particular insertion of one KP element located at the cytological site 47D1. The repression ability of the GD sterility is determined by a recessive chromosomal factor, and cannot be due to the KP-element number. Here the repression of the P mobility is associated with reduction of the P transcripts and the inhibition of P promoter activity.

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.

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