Expression levels of CAG-TAG1 transgene across four generations. TdTomato fluorescence intensity was used as a measure of transgene expression levels. TdTomato fluorescence was quantified in cardiac tissue from the CAG-TAG1 male founder (F0), and from his F1, F2, and F3 male adult offspring. The plot represents the distribution of average TdTomato fluorescence intensity per pixel for 10 different fields of view for each sample. F1, F2 and F3 mice express the transgene at equivalent levels. They do not show a significant difference in expression levels (Student t-test, P > 0.1 for all three combinations of pair-wise comparisons of the three samples). The founder has a broader distribution of average intensity per pixel and shows a lower minimum value than the others because he was mosaic for the transgene, and some of the fields of view measured had regions that did not express the transgene, causing a lowering of the average pixel intensity.