In the living cell, DNA undergoes frequent chemical change, especially when it is being replicated (in S phase of the eukaryotic cell cycle). Most of these changes are quickly repaired. Those that are...In the living cell, DNA undergoes frequent chemical change, especially when it is being replicated (in S phase of the eukaryotic cell cycle). Most of these changes are quickly repaired. Those that are not result in a mutation. Thus, mutation is a failure of DNA repair.
Mutations commonly are substitutions, in which a single nucleotide is changed into a different nucleotide. Other mutations result in the loss (deletion) or addition (insertion) of one or more nucleoti...Mutations commonly are substitutions, in which a single nucleotide is changed into a different nucleotide. Other mutations result in the loss (deletion) or addition (insertion) of one or more nucleotides. These insertions or deletions can range from one to tens of thousands of nucleotides. Often an insertion or deletion is inferred from comparison of two homologous sequences.
