The interplay between isoform multiplicity co-occurrence (IMco) and protein divergence (PD) in the generation of human-mouse phenotypic differences.

<p>Here we plot the same graph as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0072742#pone-0072742-g002" target="_blank">Figure 2A</a> with two additions: a grey-shaded area corresponding to the 50%–70% zone that separates functional from non-functional PD (see <i>Discussion</i>); a red-shaded area below the black line, highlighting the fact that the latter is an upper threshold for IMco values obtained after exclusion of non-relevant isoforms. We can see that phenotypically-relevant IMco values (red-shaded area) are always lower than 1, indicating that differences in isoform multiplicity can contribute to human-mouse phenotypic differences all over the PD range. To the right of the grey-shaded area this contribution will be more relevant than that of PD; to the left both phenomena will very likely cooperate to generate phenotypic changes; the situation is unclear within the 50%–70% zone.