Final answer:
Cytosine deamination in DNA is typically repaired by the Base Excision Repair mechanism, which excises the incorrect base and replaces it with the correct nucleotide, maintaining genetic stability.
Step-by-step explanation:
Deamination of cytosines is most likely to be repaired by Base Excision Repair. Deamination is the process where amino groups are hydrolytically removed from bases in DNA, such as cytosine. This process can lead to mutations if not corrected, as deaminated cytosine results in uracil, which pairs with adenine instead of guanine, potentially causing a C-G to T-A transition.
Finally, the backbone is sealed with a phosphodiester linkage catalyzed by DNA ligase. This pathway specializes in repairing small, non-helix-distorting base lesions, which is characteristic of deaminated cytosines, distinguishing it from other repair mechanisms such as Nucleotide Excision Repair that target bulky lesions like thymine dimers caused by UV exposure. Hence, when cytosine deamination occurs, Base Excision Repair is the primary pathway used to restore the integrity of the DNA.