One of the most powerful techniques in molecular biology is the ability to introduce changes, or mutations, at specific points in DNA. This technique is called site-directed mutagenesis. Site-directed mutagenesis needs a piece of DNA complementary to the target sequence everywhere but at the actual site, where the complement of the desired nucleotide is used instead. For example, if the T in 5'-CTG-3' needs to be changed to G, the piece of DNA needed would be 5'-CCG-3' (since complementary strands have the opposite 5' to 3' orientation).
3. In the following sequence of DNA, if the A in the 4th position is to be mutated to G, what should the sequence of the complementary strand be?
|