Fig. 3.

Maximum percentage of the intact reading frame (%intact) of genes that were preferentially lost in herbivores (A and B) and carnivores (C–F). (C) While RXFP4 is truly lost in the herbivorous pika, several other herbivores exhibit a %intact < 100% due to inactivating mutations that shorten the C terminus of the protein, but do not affect the last transmembrane domain (SI Appendix, Fig. S23). Variable C termini are relatively common in conserved genes (56) and therefore do not indicate gene loss.