BgBS90 versus BgMline schistosome resistance region PTC2

Biomphalaria glabrata is a snail intermediate host for Schistosoma mansoni, a trematode responsible for human schistosomiasis. BS90 is one of the most well studied strains of B. glabrata owing to its high resistance to infection by most strains of S. mansoni. M-line is a highly susceptible strain which is commonly used for passaging the parasite. We found a region, PTC2, which was highly correlated with infection susceptibility in 1316R snails. We tested the hypothesis that the PTC2 region contains the causal gene/s that explain the iconic resistance of BS90 snails. We used marker-assisted backcrossing to drive the BS90 version of the PTC2 region (+/- ~ 1 Mb on either side) into an M-line (susceptible strain) genetic background, and the M-line version into a BS90 genetic background. We also used an F2 cross to independently test the effects of the PTC2 region in a randomized genetic background.