Response to Burgers et al.

In our study (Johnson et al., 2015), we concluded that DNA polymerase (Pol) δ replicates both the leading and lagging DNA strands and that Pole plays no significant role in leading-strand replication. In their Letter in this issue of Molecular Cell, Burgers et al. (2016) contend that their model wherein Pole primarily replicates the leading strand still remains valid and suggest that (1) our strains contain suppressors, (2) our observed G→T mutations originate in the lagging strand, and (3) ribonucleotide incorporation data support their model.