Schematic diagram of the FASN gene (tca:658978) mapping to the C. sinensis , S. japonicum and S. mansoni genome. All orthologues of fatty acid biosynthesis genes were BLAST to three fluke genomes. Only a fatty acid synthase (FASN) gene (tca:658978) could be significantly mapped (e-value < 1e-10), but two key domains of Ketoacyl-synt and Acyl_transf_1 were not observed in all of the three species. (a) C. sinensis (scaffolds: Csin_scf23908 and Csin_scf26026); (b) S. japonicum (scaffold: SJC_000021). (c) S. mansoni (scaffold: Smp_scaff000021). AAA, ATPase family associated with various cellular activities; Acyl_transf_1, acyl transferase domain; Ketoacyl-synt, beta-ketoacyl synthase, N-terminal domain and C-terminal domain; KR, KR domain; Thioesterase, thioesterase domain.