What is alternative splicing?

• A. Transcribes RNA in the opposite direction.
• B. Yields multiple mRNA transcripts from one gene by splicing different combinations of exons.
• C. Inserts introns into mRNA after transcription.
• D. Replicates the entire gene to produce multiple copies.

Answer: (B)

Alternative splicing is the process by which a single gene can generate multiple mRNA transcripts by joining exons in different combinations during RNA processing. After transcription, the pre-mRNA carries exons and introns, and the spliceosome can select different splice sites or skip certain exons. This yields distinct mature mRNAs from the same gene, leading to different protein variants. It’s not about transcribing RNA in the opposite direction, not about inserting introns after transcription (introns are removed), and not about duplicating the gene.