a. Quantitative PCR for total and endogenous c-Myc, Klf4, Oct4 and Sox2 expression. Data is shown as relative expression to an ES cell line, E14Tg2a (E14). Error bars indicate the s.d. generated from triplicates. b. Quantitative PCR for pluripotent markers. Two independent ES cell lines, E14Tg2a (E14) and CGR8, were analyzed together with iPS cell lines. Data is shown as relative expression to E14Tg2a, and represents one of two independent experiments.