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Genetic variation in a host-parasite association: potential for coevolution and frequency-dependent selection
H J Carius1, T J Little, D Ebert
1Zoologisches Institut, Universität Basel, Switzerland. achim.carius@epost.de
Evolution; International Journal of Organic Evolution
|July 28, 2001
Summary
Genetic variation in Daphnia magna and Pasteuria ramosa populations drives host-parasite coevolution. Specific host-parasite interactions suggest parasites track host genotypes, indicating potential for frequency-dependent selection.
Area of Science:
- Evolutionary Biology
- Ecology
- Genetics
Background:
- Host-parasite coevolution models require genetic variation for resistance and infectivity.
- Genotype-specific interactions are crucial for understanding coevolutionary dynamics.
Purpose of the Study:
- Investigate genetic variation in host susceptibility and parasite infectivity.
- Determine the presence and nature of host clone-parasite isolate interactions.
- Assess the potential for frequency-dependent selection in host-parasite systems.
Main Methods:
- Utilized Daphnia magna (crustacean) and Pasteuria ramosa (bacterial microparasite).
- Examined genetic variation within two natural populations.
- Performed infection experiments to assess host resistance and parasite infectivity.
Main Results:
- Significant variation in host resistance and parasite infectivity was observed.
- Identified significant host clone-parasite isolate interactions, preventing a universally resistant host or universally infective parasite.
- Original host-parasite combinations showed higher infection success than novel combinations.
Conclusions:
- Host-parasite interactions in this system support coevolution via frequency-dependent selection.
- Parasites appear to track specific host genotypes under natural conditions.
- Shared resistance genes may exist among host clones distinguishable by neutral markers.