Correlation of lentiviral insertion sites and vector copy number. (A) For each animal of the second experiment, the relation of unique insertions per time point versus vector copy number in peripheral blood samples was determined. (B) For all animals of the first and second experiment, the relation of unique insertions per time point versus vector copy number in end-point peripheral blood samples was determined. Statistical testing was done with the Mann-Whitney 2-sided test. *P < .05; **P < .01; ***P < .001.