Regarding comparisons of gonad-specific and pairing-dependent gene expression (i.e. single-sex infections versus bi-sex infection) performed by Lu et al. [34], Smp_034000 KDM6A expression in the testes was two-fold higher than the rest of the parasite body in male worms in both single-sex male infection and bi-sex infection models (Additional file 2: Figure S2b). Here, KDM6A is linked to infection.