Final answer:
Deamination of 5-methyl cytosine can result in the conversion of cytosine to uracil, causing a base substitution mutation.
Step-by-step explanation:
Deamination of 5-methyl cytosine can result in the conversion of cytosine to uracil, leading to a base substitution mutation. This occurs when the amino group (-NH2) is hydrolytically removed from the cytosine base, resulting in the formation of uracil. During DNA replication, the altered strand with uracil will pair with adenine instead of guanine, causing a G-C base pair to be replaced with an A-T pair.