The RFP(Unk) entry in FlyBase represents a red fluorescent protein where the gene of origin is unknown/unspecified. A transgene or modified endogenous locus annotated in FlyBase as being tagged with RFP(Unk) is likely tagged with a fluorescent protein derived either from the Discosoma drFP583 gene (GenBank:AF168419; AAF03369) or from the Entacmaea quadricolor eqFP578 gene.