P-MaleReg · Establishment of P-element silencing in Drosophila simulans dysgenic males
Horizon 2020 — Marie Skłodowska-Curie Actions
- Duration
- 2019-01-16 → 2021-04-15
- EU contribution
- €183,455
- Participants
- 1
- Scheme
- MSCA-IF-EF-ST
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Results in brief
Establishment of P-element silencing in Drosophila simulans dysgenic males
Genomes are thought of blueprints-- collections of the genetic instructions for development and function and organisms. But genomes also contain other material, often including substantial amounts of parasitic DNA, in the form of transposable elements (TEs). TEs act as parasites by using their host genomes replication and metabolic machinery to reproduce themselves. They are successful parasites when they replicate within genomes faster than their hosts' own genes; in fact, they can be so successful that they make up major fractions of the genomes of a wide variety of organisms. Like many parasites, TEs can also be harmful: as they replicate within genomes, they necessarily break the backbone of the DNA molecule, which can disrupt host genes and threaten the integrity of the genome. Hence, organisms have evolved to repress TE replication, especially in reproductive cells (e.g., eggs and sperm), where new mutations can be transmitted to offspring. As a result, active TEs tend to be those that have only recently invaded host genomes from another species. In this project, we are investigating the evolution of host repression of TEs, taking advantage of an active TE that has recently invaded a fruit fly (Drosophila) species. Most similar work focuses on females, where transposable elements can have a major effect on fertility. Here, we focused on males. First, we asked if the TE also has a negative effect on male fertility, showing that it does. Second, we asked if the flies have evolved suppression of the TE in the testes as a result; results from this part of the project are forthcoming. As a result of their important impact on the genomes of so many organisms, understanding the basic biology of TEs is a societal good, which may have long-term benefits in understanding the biology of genetic disease.
Data: CORDIS, © European Union
Project objective
Transposable elements (TEs) are mobile genetic parasites infecting the genomes of most organisms, so abundantly as to be a major determinant of genome size in eukaryotes. They can be harmful, as their ability to mobilise makes them highly mutagenic and a threat to host genome integrity. Hence, organisms have evolved several TE repression mechanisms, especially in the germline, where new mutations can be transmitted to progeny. TEs challenge these silencing strategies by invading new genomes through horizontal transfer, but hosts appear to rapidly adapt to these new TEs. The classic example is the invasion of the Drosophila melanogaster genome by the P-element: TE repression in this system evolved so quickly that the P-element and its repressors (recently discovered to be due to a small RNA pathway) appeared almost simultaneously. The selective pressure may have been intense: crosses between D. melanogaster males containing P-elements and females devoid of it lead to frequent F1 sterility and other aberrant traits. This phenomenon, associated with uncontrolled P-element mobilization, is named “hybrid dysgenesis”. Due in part to its rapidity, little is known about the early stages of TE repression evolution. In this work, we propose to take advantage of a rare opportunity to study the adaptation to a TE invasion in real time. Less than a decade ago, the P-element invaded the genome of D. simulans, a sister species of the genetic model. We aim to disentangle the molecular mechanisms involved in the establishment of P-element silencing in D. simulans. In particular, we will study the effects of dysgenesis and repression in males, which have been largely neglected to date. As a result, their role in the rapid spread of the P-element remains elusive. This work will contribute to deciphering how TE silencing is established during novel TE invasions, a crucial part of understanding the dynamics between TEs and their hosts.
Original text from CORDIS.
Participants
- THE UNIVERSITY OF LIVERPOOL · LIVERPOOLCoordinatorUnited Kingdom
Links
Data: CORDIS, © European Union