RNA type primarily involved in gene silencing by base pairing with complementary mRNA sequences

• A. mRNA
• B. microRNA
• C. rRNA
• D. tRNA

Answer: (B)

MicroRNA is the RNA type that silences genes by base pairing with complementary mRNA sequences. These small noncoding RNAs are processed and incorporated into a silencing complex with an Argonaute protein. The microRNA guide uses its seed region to find matching sites, usually in the target mRNA’s untranslated region, and binding recruits the complex to block translation or promote mRNA degradation. This post-transcriptional regulation is how gene expression is tuned without changing the underlying DNA. In contrast, mRNA carries the genetic message for protein synthesis, rRNA forms the ribosome’s structural and functional core, and tRNA delivers amino acids during translation, not gene silencing via base pairing with mRNA.