What is wobble base pairing and why does it matter?

• A. Non-standard base pairing at the 3' end of codon-anticodon interactions allows some tRNAs to recognize multiple codons, contributing to degeneracy.
• B. It increases fidelity by proofreading.
• C. It only occurs during DNA replication.
• D. It enhances fidelity by ensuring exact matching.

Answer: (A)

Wobble base pairing describes non-standard hydrogen bonding at the third position of the codon–anticodon interaction, letting a single tRNA recognize more than one codon. This flexibility explains why the genetic code is degenerate: many amino acids are encoded by multiple codons, yet cells can translate efficiently with relatively few tRNA species. Mechanistically, certain nonstandard pairings occur, such as G pairing with U, and inosine in the anticodon pairing with A, U, or C. This happens during translation, not DNA replication, and it isn’t about proofreading or forcing exact matching; instead, it provides tolerance for variation while the cell maintains overall accuracy through other fidelity safeguards. So, wobble base pairing matters because it lets tRNAs read multiple codons, contributing to codon degeneracy.