Definition of Mismatch repair

Mismatch repair: A system within the cell for correcting errors in DNA that works by detecting and replacing bases in the DNA that are wrongly paired (mismatched bases). The system repairs the mismatch.

When there is a mismatch in the DNA, a mismatch correction enzyme goes to that strand of DNA and removes a segment of the strand containing the mismatched base. The gap in the strand is then filled through the action of the enzyme DNA polymerase.