Compatibility and sex in a snail-schistosome system

Knowledge of the genetics underlying resistance to parasitic infection has important repercussions for our understanding of infection dynamics and the mechanisms of host-parasite co-evolution. The aim here was to determine fo r a Biomphalaria glabrata-Schistosoma mansoni system whether (1) resistance is dominant over susceptibility, (2) it is possible to crossbreed snails t o be simultaneously resistant and/or susceptible to more than one parasite strain and (3) compatibility genotype affects reproductive strategy. Using replicate snail strains artificially selected for either resistance or susc eptibility to single replicate parasite strains, individual snails from eac h line were paired with a selected partner of matched or non-matched compat ibility status and cross-breeding was identified by RAPD-PCR. The resulting compatibility phenotype of all offspring was determined. Support for all 3 hypotheses were obtained. The results are discussed in terms of their appl ied and theoretical implications.