TI - Results dFOXO is the only Drosophila homolog of FOXO and DAF-16 . AB - The Drosophila genome contains a single homolog of the DAF-16/FOXO family of transcription factors . This notion is supported by the phylogenetic tree diagram calculated from the multiple sequence alignment ( Figure 1a ) . The dFOXO gene is more closely related to the mammalian FOXO subfamily and daf-16 than any other Drosophila forkhead gene . The amino-acid sequences of the predicted 613 amino-acid dFOXO protein and hFOXO3a are 27% identical over the full protein length , and 82% identical within the forkhead DNA -binding domain . Furthermore , dFOXO is the only Drosophila forkhead gene encoding a putative protein containing conserved PKB PHOSphorylation sites [37] . The orientation of the three PKB consensus sites relative to the forkhead domain ( Figure 1b ) is conserved among the mammalian FOXO proteins , DAF-16 and dFOXO . Figure 1c shows the high degree of sequence conservation between dFOXO and FOXO/DAF-16 proteins within the DNA -binding domain . Taken together , these observations strongly suggest that dFOXO is the only Drosophila homolog of the mammalian FOXO transcription factors and C.elegans DAF-16 .