Which mechanism is used specifically for removing and replacing a damaged segment of DNA?

Nucleotide excision repair is a mechanism specifically designed to identify and remove damaged segments of DNA, particularly those induced by bulky DNA adducts, UV light, and other environmental factors. This process involves the recognition of the damaged DNA, the cutting of the DNA strand on either side of the lesion, and the removal of the damaged segment. Subsequently, DNA polymerase synthesizes new DNA to fill in the gap, followed by DNA ligase sealing the strand to restore the integrity of the DNA molecule.

This specificity makes nucleotide excision repair a critical pathway for maintaining genomic stability, especially in response to extensive DNA damage that cannot be corrected by more straightforward repair mechanisms. Other types of repair mechanisms, while they also play important roles in maintaining DNA integrity, are focused on different types of damage or errors, such as single base modifications or mismatches, rather than larger or more complex sections of the DNA strand.