Question: Proteins such as Dicer and RDE-4 that are involved in RNAi and miRNA inactivation of target gene expression are present in most eukaryotes. However, some eukaryote species do not naturally produce double stranded RNA and yet still retain the presence of Dicer and RDE-4. Given that as a background, what is the most likely reason why these genes are evolutionarily retained in nearly all eukaryotes?