Q. Spontaneous deamination of cytosine:
1. Deamination of cytosine is common and results in conversion of cytosine to uracil 2. can be repaired by excision repair process (i) uracil-DNA glycosylase hydrolyzes N-glycosidic bond to remove uracil base (ii) AP endonuclease removes deoxyribose-phosphate (iii) gap is extended by exonuclease (iv) gap is filled by DNA polymerase I and nick is sealed by DNA ligase