Class       : Insecta
  Order       : Diptera
  Suborder    : Brachycera
  Clade       : Cyclorrhapha
  Superfamily : Ephydroidea
  Family      : Drosophilidae

NCBI:txid7238

Annotation from assembly GCA_004382195.2, WGS project NIFZ01.1

The sequences include the two forms of the alternatively spliced CYP4D1 (CYP4D1_v1a /v1b).

A FASTA format file of the CYPome can be downloaded here

The distribution of genes by CYP clan is tabulated here

Drosophila sechellia recently diverged from D. melanogaster (about 3 - 5.4 MYA) and D. simulans (about 0.5 MYA), and is now a specialist feeder on the fruit of Morinda citrifolia (noni) that is highly toxic to other fruit flies. Several authors speculated that specialization led to a loss of P450s, while others felt that the host fruit toxicity might be associated to higher P450 numbers. Thus, Good et al., 2014 reported a CYPome size of 74 functional genes and 14 pseudogenes. Rane et al. (2019) in a comparison of 14 Drosophila species later reported a CYPome size of 96.

This annotation gives 77 functional genes, 11 pseudogenes and 1 gene fragment.

When compared to D. melanogaster, D. sechellia has lost 8 genes to pseudogenes, with 2 genes lost without a trace. Reciprocally, the D. melanogaster pseudogenes CYP6A16P and CYP9F3P are functional genes in D. sechellia. Both species have the pseudogenes CYP6A15P and CYP6T2P in common, and D. sechellia has a duplication of CYP6T1, with one functional and one pseudogene version.

D. sechellia also has a CYP12D3P pseudogene, a gene lost in D. melanogaster but functional in D. simulans. Although McDonnell et al. (2012) claim that CYP12D1 duplicated once in the Drosophila lineage, it is more likely that the CYP12D1/12D3 is an ancient duplication, while the D. melanogaster CYP12D1d/12D1p duplication is a very recent one. Their prediction that “based on its signature of positive selection […] CYP12D3 in D. sechellia has evolved a function unique to this species” is not supported by the fact that it is found as a pseudogene in the two publicly available genome assemblies (as of 2024), and that it is highly similar to the D. simulans sequence.

This annotation generally agrees with that of Good et al., 2014, and illustrates the dynamic nature of the Drosophila CYPome over a short time of divergence and speciation.