Fig. 10

Detailed view of protein BSUD.12903 containing the alternatively expressed exon of 741 aa, which demonstrates that in the extracellular region nonsynonymous diversity greatly exceeds synonymous diversity (shown here in 50 aa sliding windows) in regions where functional domains potentially involved in pathogen recognition are present (C-type lectin, immunoglobulin, and fibronectin III (FN3) domains). Two inbred lines of Biomphalaria sudanica (Bs111 and Bs5-2) have multiple nonsense variants (stop codon or frameshift) in a single exon containing a FN3 domain, which is expressed in the B. pfeifferi ortholog (KAK0057508 [8]), suggesting that FN3 may not be expressed in all B. sudanica lines. The FN3 exon also occurs in the B. glabrata ortholog BGLB024560, where it is also variably either expressed (NCBI Accession XM_056010427) or excluded (NCBI Accession SRX8534561). Both FN3 and/or TMEM154 domains are present in B. sudanica genes BSUD.8884, BSUD.8874 and BSUD.8876 that are orthologous to B. glabrata PTC1 region genes associated with schistosome resistance: grctm2, grctm3 and grctm4 [41]