Median JIS over all 15mer fragments, treating predicted non-binders as the lowest JIS, for each of a set of different human-host viruses. The medians of the representative viruses EBV, CMV, Marburg, Ebola are indicated at the bottom, along with the median over all fragments in the plant-host virus set. The additional viruses are plotted at their median JIS, staggered in y value. Rubella is not shown, as over 50% of its peptides are non-binders. The curve provides a kernel density estimation of the median JIS distribution.