The first three nucleotides of a six-nucleotide palindromic restriction site are CAG; what are the next three? (Note: only the coding strand is shown.)

Question

Quizplus · Accepted Answer

A palindromic DNA sequence reads the same on both the forward and reverse strands. If the first three nucleotides of a palindromic restriction site are CAG, then the complementary sequence on the other strand should also be CAG, which gives rise to CTG on the original strand as the next three nucleotides. Therefore, the answer is B.

The First Three Nucleotides of a Six-Nucleotide Palindromic Restriction Site