Eight litters of mice were used to obtain a sufficient number of mice for statistically valid results, with similar numbers, and levels of CD34+ cells in mice within each litter allocated for infection with HTLV-1-WT, HTLV-1-p12stop, or HTLV-1-CTCF (Figs 1 and S1 and S1 Table). This evidence concerns the gene CD34 and infection.