====== Drosophila sechellia ======

{{ ::sechellia.jpg?200|}}

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




NCBI:txid[[https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=7238|7238]]

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 {{ ::sechellia.fasta |here}} 

The distribution of genes by CYP clan is tabulated [[CYPfam_by_clan|here]]

//Drosophila sechellia// recently diverged from //[[drosophila|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, [[https://doi.org/10.1093/gbe/evu083|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 //[[drosophila|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 [[https://doi.org/10.1093/gbe/evu083|Good et al., 2014]], and illustrates the dynamic nature of the Drosophila CYPome over a short time of divergence and speciation.