Related Experiment Videos
Variability within the Seychelles cytoplasmic incompatibility system in Drosophila simulans
H Merçot1, B Llorente, M Jacques
1Institut Jacques Monod, laboratoire Dynamique du Génome et Evolution, CNRS-Université Paris, France.
Genetics
|November 1, 1995
Summary
A new cytoplasmic incompatibility (CI) system in Drosophila simulans, the Seychelles CI type, arises from the interaction between two distinct Wolbachia variants (wHa and wNo). This interaction leads to bidirectional incompatibility between flies infected with different Wolbachia combinations.
Area of Science:
- Evolutionary biology
- Genetics
- Microbiology
Background:
- Cytoplasmic incompatibility (CI) is a reproductive mechanism mediated by Wolbachia bacteria in insects.
- The Seychelles CI system in Drosophila simulans was previously linked to a specific mitochondrial type (SiI).
- Populations harboring the Seychelles CI system exhibit heterogeneity in Wolbachia infections, with some having single (wHa) or dual (wHa and wNo) variants.
Purpose of the Study:
- To investigate the specific Wolbachia variants responsible for the Seychelles CI type.
- To characterize the reproductive incompatibility conferred by individual Wolbachia variants, particularly wNo.
- To understand the complex interactions between different Wolbachia variants within Drosophila simulans.
Main Methods:
- Experimental infection of Drosophila simulans strains with specific Wolbachia variants (wHa and wNo).
- Cross-mating experiments to assess reproductive compatibility between different Wolbachia-infected strains.
- Analysis of Wolbachia transmission patterns, including maternal transmission efficiency.
Main Results:
- Two Drosophila simulans strains exclusively infected with the wNo Wolbachia variant were experimentally generated.
- The wNo variant confers its own distinct type of cytoplasmic incompatibility.
- Crosses between wNo-infected and wHa-infected flies resulted in bidirectional incompatibility.
- The Seychelles CI type, strictly defined, is caused by the mutual incompatibility of two simultaneously present Wolbachia variants (wHa and wNo).
- Incomplete maternal transmission of Wolbachia was observed.
Conclusions:
- The Seychelles CI system is characterized by the complex interplay between at least two mutually incompatible Wolbachia variants (wHa and wNo).
- The wNo variant plays a crucial role in defining a specific CI phenotype.
- Understanding these Wolbachia-host-pathogen interactions is key to explaining reproductive isolation and population dynamics in Drosophila simulans.