Copy number variation (CNV)

The “reference” genomes may have fewer or more CYP genes than are found in a natural population. In the two initial reference human genomes, Craig Venter's (Science 2001) has two copies of CYP1A2 and the anonymous public genome (Nature 2001) is deficient in CYP2D6 (CYP2D6*5 deletion allele).

CYP6P9 a and b in Anopheles funestus are highly overexpressed and are responsible for pyrethroid resistance (Wondji et al., 2009; Riveron et al., 2013)

A survey of eight Bemisia tabaci genomes (Campbell et al., 2023, Table S11) reported P450 numbers ranging from 89 to 105 (both African cassava whiteflies from different locations in Nigeria). The “reference” genome (B.tabaci sensu stricto, “MED”) had 93 P450s.