Polymorphism within Fasciola hepatica. (a) Levels of non-synonymous polymorphism for F. hepatica genes exhibiting orthology with Clonorchis, Schistosoma, Schmidtea or Echinococcus indicated within the phylogenic tree. Numbers by branches refer to numbers of orthologous groups specifically shared by that branch; for example, 464 orthologs are shared only between Fasciola and Clonorchis, a further 388 are also shared with Schistosoma but not with Schmidtea or Echinococcus and so on. Branches not drawn to scale. Polymorphism is significantly (P <0.001) higher in Fasciola orthologs shared among the digenean and cestode parasites Clonorchis, Schistosoma and Echinococcus (green, red and blue crosses, respectively) relative to orthologs conserved with the turbellarian Schmidtea (black dots). (b, c) Directed acyclic graphs indicating over-representation of biological processes within the top 1% most polymorphic genes, based on non-synonymous diversity. Shaded boxes indicated significant (P <0.01) over-representation. Black and blue arrows indicate, respectively, ‘is a’ and ‘part of’ relationships between terms.