Question

Small single‐stranded RNAs called micro RNAs (miRNAs) are about 21 nucleotides long and act to inhibit expression of specific genes. Describe how such RNAs are made and the mechanisms responsible for their inhibition of gene expression. During formation of sperm, activation of selfish genetic elements called retrotransposons is inhibited by a special class of short interfering RNAs (siRNAs) called piRNAs that are slightly longer than miRNAs. Based on your knowledge of RNA interference mechanisms, how might piRNAs inhibit retrotransposons? What are the advantages and disadvantages of having active retrotransposons in cells?

Answer 1

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