Which of the following DNA polymerases is responsible for synthesizing the majority of the leading strand during DNA replication in eukaryotes?

Explanation

## DNA Polymerases in Eukaryotic Replication **Key Point:** DNA polymerase ε (Pol ε) is the primary replicase responsible for synthesizing the leading strand continuously in eukaryotes. ### Roles of Major Eukaryotic Polymerases | Polymerase | Primary Function | Strand | Processivity | Key Feature | |---|---|---|---|---| | Pol α | Primer synthesis | Both | Low | Primase activity; initiates replication | | Pol δ | Lagging strand synthesis | Lagging | High | Synthesizes Okazaki fragments | | Pol ε | Leading strand synthesis | Leading | High | Main replicase for continuous synthesis | | Pol γ | Mitochondrial DNA replication | mtDNA | High | Only polymerase in mitochondria | **High-Yield:** Pol ε and Pol δ are the two main replicases in eukaryotes. Pol ε handles the leading strand (continuous), while Pol δ handles the lagging strand (discontinuous Okazaki fragments). **Mnemonic:** **LEAD-ε** — Pol ε synthesizes the LEADing strand; **LAG-δ** — Pol δ synthesizes the LAGging strand. **Clinical Pearl:** Mutations in Pol ε are associated with Lynch syndrome (hereditary nonpolyposis colorectal cancer, HNPCC) due to impaired mismatch repair coupling.