If ADH and ALDH act in a linear pathway, the phenotype of loss of the upstream gene should not be enhanced by loss of the downstream gene. We tested this by knocking down function of either alh-6 or alh-13 in a sodh-1(ok2799) background, and found that the phenotype of the combinations was not different from that of sodh-1 alone (Figure 4b, 4c). This result provides further support for the linear nature of the metabolism pathway, and further strongly suggests that the ethanol hypersensitivity phenotypes of sodh-1(ok2799), alh-6(RNAi) and alh-13(RNAi) are due to changing ethanol metabolism.
