Cytochrome P450 diversification and hostplant utilization patterns in specialist and generalist moths: birth, death, and adaptation

Across insect genomes, the size of the cytochrome P450 monooxygenase (CYP) gene superfamily varies widely. CYPome size variation has been attributed to reciprocal adaptive radiations in insect detoxification genes in response to plant biosynthetic gene radiations driven by coevolution between herbivores and their chemically defended hostplants. Alternatively, variation in CYPome size may be due to random “birth and death” processes, whereby exponential increase via gene duplications is limited by random decay via gene death or transition via divergence. We examined CYPome diversification in the genomes of seven Lepidoptera species varying in host breadth from monophagous (Bombyx mori) to highly polyphagous (Amyelois transitella). CYPome size largely reflects the size of Clan 3, the clan associated with xenobiotic detoxification, and to some extent phylogenetic age. Consistently across genomes, families CYP6, CYP9, and CYP321 are most diverse and CYP6AB, CYP6AE, CYP6B, CYP9A, and CYP9G a...