Taking a close look at sex: Amazon mollies and their parasites

Michael Tobler (Ph. D. student)

The evolution and maintenance of sex and recombination is still a major and unresolved paradox in evolutionary biology. Currently, one of the most widely accepted hypotheses, the Red Queen hypothesis, states that recombination provides an immediate advantage in biotic interactions. More specifically, the Red Queen hypothesis argues that recombination results in genetically diverse offspring that, contrary to the uniform offspring of asexuals, are difficult targets for parasites and diseases.
The Amazon molly, Poecilia formosa, is one of the few clonal vertebrates, reproduces gynogenetically and thus always has to coexist with a closely related sexual species. The mating system of P. formosa and its sexual relatives is an ideal model system to investigate advantages of sexual reproduction and testing the predictions of the Red Queen.

Current projects focus on:

• spatial and temporal patterns of parasitisation in natural populations of sexual and asexual mollies
• population genetics of sexual and asexual mollies including genes at MHC-loci, especially the temporal variation in clonal diversity of P. formosa
• the immunocompetence of sexual and asexual mollies under controlled experimental conditions
• the effects of Blackspot disease on the life history and the behavior of mollies
  
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