Fig. 9.

A mathematical model of LIR motif functionality in co-evolving hosts and pathogens. a The equilibrium outcomes when different assumptions about infection recovery rate and mortality (Effects I–IIIb described in the main text) are applied separately or in combination. The host type(s) present at equilibrium are indicated by the different colored and numbered squares and the pathogen types by triangles. An upright triangle indicates the pathogen circulating at equilibrium can express a LIR motif, a downturned triangle indicates the pathogen does not express a LIR motif. For a description of the model and all parameter values, see Methods section and Supplementary Table 5. b Time series showing the dynamics leading up to equilibrium under three different sets of conditions: applying none of the effects in the main text, resulting in a Drosophila–like scenario; applying Effects I and IIIb leading to a human-like host and a LIR expressing pathogen at equilibrium; and applying Effects I and IIIa, leading to an equilibrium population where host IKKγ is regulated by both LIR and ubiquitin degradation. The different colored lines show the proportion of the host population belonging to a particular host type and the triangular markers indicate the proportion of the population infected with a pathogen that can express LIR (downturned triangle) or a pathogen that cannot express LIR (upturned triangle)