Schematic diagram showing the genomic organization of daf-2 from Haemonchus contortus (Hc-daf-2), Caenorhabditis elegans (Ce-daf-2) (Kimura et al., 1997) and Strongyloides stercoralis (Ss-daf-2a and Ss-daf-2b) (Massey et al., 2013). Black boxes represent exons. The lines between the exons represent introns. The structural domains encoded by Hc-daf-2 are marked on the top of diagram of Hc-daf-2 gene, located to the corresponding positions. Arrows indicate the start (ATG) or stop codon (TGA). L, ligand binding loop; CR, cysteine-rich region; FN, fibronectin type domains; TM, transmembrane domain; TK, tyrosine kinase domain.