Which of the following lists the three main factors that contribute to the high fidelity of DNA replication?

• A. Transcriptional regulation, chromatin remodeling, and histone modification
• B. Complementary base pairing, proofreading by DNA polymerase, and mismatch repair
• C. RNA splicing, alternative polyadenylation, and exon shuffling
• D. Ligase activity, Okazaki fragment synthesis, and telomerase extension

Answer: (B)

Verified step by step guidance

1. Identify the key concept: The question asks for the three main factors that ensure the high fidelity (accuracy) of DNA replication.
2. Recall the process of DNA replication and the mechanisms that maintain accuracy: DNA replication fidelity depends on how accurately the DNA polymerase incorporates nucleotides, how errors are corrected during replication, and how remaining errors are fixed after replication.
3. Understand each option: Transcriptional regulation, chromatin remodeling, and histone modification relate to gene expression control, not replication fidelity; RNA splicing, alternative polyadenylation, and exon shuffling are post-transcriptional processes; ligase activity, Okazaki fragment synthesis, and telomerase extension are important for replication completion but not directly for fidelity.
4. Focus on the correct answer components: Complementary base pairing ensures correct nucleotide incorporation; proofreading by DNA polymerase corrects errors immediately during replication; mismatch repair fixes errors missed by proofreading after replication.
5. Summarize that the three main factors contributing to high fidelity of DNA replication are complementary base pairing, proofreading by DNA polymerase, and mismatch repair.