Data from: 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
are most diverse among subfamilies. Higher gene number in subfamilies is
due to duplications occurring primarily after speciation and
specialization (“P450 blooms”), and the genes are arranged in clusters,
indicative of active duplicating loci. In the parsnip webworm, Depressaria
pastinacella, gene expression levels in large subfamilies are high
relative to smaller subfamilies. Functional and phylogenetic data suggest
a correlation between highly dynamic loci (reflective of extensive gene
duplication, functionalization, and in some cases loss) and the ability of
enzymes encoded by these genes to metabolize hostplant defenses,
consistent with an adaptive, nonrandom process driven by ecological
interactions.