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Susceptibility of natural hybrids between house mouse subspecies to Sarcocystis muris
J M Derothe1, N Le Brun, C Loubes
1Laboratoire Génome, Populations, Interactions, UMR 5000 CNRS - UMII, cc 105, Université Montpellier II, 34095 cedex 05, Montpellier, France.
Abstract:
A previous study showed that the susceptibility of hybrids between two Mus musculus musculus and Mus musculus domesticus did not apply to every parasite. The authors proposed that only parasites which exerted enough constraints would induce the selection of poorly compatible systems of resistance in the subspecies. This study completes the previous work. Experimental infections of mice of the two subspecies and their hybrids with the tissue-dwelling protozoan Sarcocystis muris show that hybrids are more susceptible to the coccidian than M. m. musculus and M. m. domesticus individuals. This result demonstrates that the hybrids are not only susceptible to intestinal helminths, and confirms the 'constraint hypothesis'.
Insights
Hybrid mice show increased susceptibility to the protozoan parasite Sarcocystis muris. This finding supports the constraint hypothesis, suggesting parasite-induced selection pressures influence resistance in mouse subspecies.
Area of Science:
- Immunology
- Parasitology
- Genetics
Background:
- Previous research indicated that parasite susceptibility in hybrids of Mus musculus musculus and Mus musculus domesticus varied.
- The 'constraint hypothesis' proposed that only parasites exerting significant selective pressure would drive incompatibilities in resistance systems between subspecies.
Purpose of the Study:
- To investigate the susceptibility of mouse subspecies and their hybrids to the tissue-dwelling protozoan Sarcocystis muris.
- To further validate the 'constraint hypothesis' by examining hybrid responses to a different class of parasite.
Main Methods:
- Experimental infection of Mus musculus musculus, Mus musculus domesticus, and their hybrid mice with Sarcocystis muris.
- Comparative analysis of susceptibility levels across the different mouse groups.
Main Results:
- Hybrids exhibited significantly higher susceptibility to Sarcocystis muris compared to both parental subspecies.
- This enhanced susceptibility in hybrids was observed for a protozoan parasite, extending beyond previously studied helminths.
Conclusions:
- The results confirm and strengthen the 'constraint hypothesis'.
- Parasite-driven selective pressures play a crucial role in shaping host resistance mechanisms and incompatibilities between Mus subspecies.