We evolved populations of E. coli under strict genetic drift effects by transferring a single colony daily to a fresh plate. The E. coli is the strain K12 substrain MG1655 with a mutS deletion. Two evolved populations (line A and B) were sequenced at different time points of the evolution experiment - line A at passage 100, 200, 250 and 260 and line B at passage 15, 200 and 250.