Leukemogenic molecular clones trigger higher levels of early BLV replication than attenuated infectious molecular clones in vivo. Time-point data were pooled and compared between leukemogenic and attenuated infections. A: proviral copy (VCN) number per mcg of DNA; B: overall number of circulating infected cellular clones; C: Numbers of abundant clones were defined as those giving two or more signals after semiquantitative quadruplicate IPCR, i.e. those corresponding to ≥ 62.5 copies in 1 mcg of circulating DNA  ; D: infected cellular clones with < 62,5 copies per mcg of DNA. The boxes represent the difference between the 75th percentile and the 25th percentile of the variables (i.e., the interquartile range). Within the inset box, the median is represented by a thick horizontal line. Lines from the ends of the box extend as far as the most extreme values not considered outliers. Points more than 1.5 times the interquartile range from the ends of the box are labeled as outliers ([open circle]) or as extreme values ([low asterisk]).