When strand slippage occurs during DNA replication, a DNA strand may loop out, resulting in the addition or deletion of a nucleotide on the newly-synthesized strand. ... But if this does not occur, a nucleotide that is added to the newly synthesized strand can become a permanent mutation.
A mutation is a change that occurs in our DNA sequence, either due to mistakes when the DNA is copied or as the result of environmental factors such as UV light and cigarette smoke. Mutations can occur during DNAreplication if errors are made and not corrected in time.
