Evolution of the Insect PPK Gene Family

JOSE MANUEL LATORRE-ESTIVALIS; FRANCISCA C ALMEIDA; GINA PONTES; HERNAN DOPAZO; ROMINA B BARROZO; MARCELO GUSTAVO LORENZO

Genome Biology and Evolution

Oxford, UK : Oxford University Press

Lugar: Oxford; Año: 2021 vol. 1

1759-6653

Insect pickpocket (PPK) receptors mediate diverse functions, among them the detection of mechano- and chemo-sensory stimuli.Notwithstandingtheirrelevance,studiesontheirevolutiononlyfocusedonDrosophila.Wehaveanalyzedthegenomesof26speciesof eight orders including holometabolous and hemimetabolous insects (Blattodea, Orthoptera, Hemiptera, Phthiraptera,Hymenoptera, Lepidoptera, Coleoptera, and Diptera), to characterize the evolution of this gene family. PPKs were detected in allgenomes analyzed, with 578 genes distributed in seven subfamilies. According to our phylogeny, ppk17 is the most divergentmember, composing the new subfamily VII. PPKs evolved under a gene birth-and-death model that generated lineage-specificexpansionsusuallylocatedinclusters,whilepurifyingselectionaffectedseveralorthogroups.SubfamilyVwasthelargest,includingamosquito-specific expansion that can be considered a new target for pest control. PPKs present a high gene turnover generatingconsiderable variation. On one hand, Musca domestica (59), Aedes albopictus (51), Culex quinquefasciatus (48), and Blattellagermanica (41) presented the largest PPK repertoires. On the other hand, Pediculus humanus (only ppk17), bees, and ants (6?9)hadthesmallestPPKsets.AsubsetofprevalentPPKswasidentified,indicatingveryconservedfunctionsforthesereceptors.Finally,atleast 20% of the sequences presented calmodulin-binding motifs, suggesting that these PPKs may amplify sensory responsessimilarly as proposedforDrosophila melanogaster ppk25. Overall, thiswork characterized the evolutionary history ofthesereceptorsrevealing relevant unknown gene sequence features and clade-specific expansions.