Chemistry
DNA Replication Fidelity: Base Pairing and Proofreading
Quick fact
DNA polymerase is so accurate that it introduces an error only about once per 10^5 base pairs, and with proofreading that rate drops to roughly one in 10^7 to 10^9.
Why this is interesting
When a cell copies its DNA, it makes only about one mistake for every ten billion letters copied. How does a molecular machine achieve such precision?