Mutations arise in 2 diff. Now consider rep. and repair errors. DNA rep., repair and mutation intimately related. E. coli expts. So, many wrong bases inserted during ea.
Environmental mutagens are also a prob.
Increase rate of error. Add 750 base pairs to each growing point per sec. B. DNA rep. In eukaryotes analogous replicase is DNA polymerase alpha. Incapable of initiating DNA synthesis .