Table 1 Sequence mutations are more commonly encountered when constructing shRNA templates by primer extension using Taq rather than Phi29. A representative subset of sequencing results for a selection of constructs that were made twice, once using Taq and once using Phi29. Constructs generated by Taq were more prone to mutations than when made with Phi29. Both substitutions and deletions were commonly encountered. These were positioned in either the stem or the loop encoding regions. Templates generated by Phi29 were not refractory to mutations (*); however, the frequency and extent of mutation was below that observed for Taq (in this case we found 50 % (8/16) of Taq generated constructs contained mutations versus 10 % of similar constructs made with Phi29).

From: Design and cloning strategies for constructing shRNA expression vectors