title: Genome-Wide Comparative Analysis of Chemosensory Gene Families in Five Tsetse Fly Species.
abstract: For decades, odour-baited traps have been used for control of tsetse flies (Diptera; Glossinidae), vectors of African trypanosomes. However, differential responses to known attractants have been reported in different Glossina species, hindering establishment of a universal vector control tool. Availability of full genome sequences of five Glossina species offers an opportunity to compare their chemosensory repertoire and enhance our understanding of their biology in relation to chemosensation. Here, we identified and annotated the major chemosensory gene families in Glossina. We identified a total of 118, 115, 124, and 123 chemosensory genes in Glossina austeni, G. brevipalpis, G. f. fuscipes, G. pallidipes, respectively, relative to 127 reported in G. m. morsitans. Our results show that tsetse fly genomes have fewer chemosensory genes when compared to other dipterans such as Musca domestica (n>393), Drosophila melanogaster (n = 246) and Anopheles gambiae (n>247). We also found that Glossina chemosensory genes are dispersed across distantly located scaffolds in their respective genomes, in contrast to other insects like D. melanogaster whose genes occur in clusters. Further, Glossina appears to be devoid of sugar receptors and to have expanded CO2 associated receptors, potentially reflecting Glossina's obligate hematophagy and the need to detect hosts that may be out of sight. We also identified, in all species, homologs of Ir84a; a Drosophila-specific ionotropic receptor that promotes male courtship suggesting that this is a conserved trait in tsetse flies. Notably, our selection analysis revealed that a total of four gene loci (Gr21a, GluRIIA, Gr28b, and Obp83a) were under positive selection, which confers fitness advantage to species. These findings provide a platform for studies to further define the language of communication of tsetse with their environment, and influence development of novel approaches for control.
authors.affiliation: Molecular Biology and Bioinformatics Unit, International Centre of Insect Physiology and Ecology, Nairobi, Kenya.|South African National Bioinformatics Institute, University of the Western Cape, Cape Town, South Africa.
authors.forename: Rosaline
authors.initials: R
authors.lastname: Macharia
authors.affiliation: Department of Epidemiology of Microbial Diseases, Yale School of Public Heath, New Haven, Connecticut, United States of America.|Biotechnology Research Institute, Kenya Agricultural and Livestock Research Organization, Kikuyu, Kenya.
authors.forename: Paul
authors.initials: P
authors.lastname: Mireji
authors.affiliation: Department of Biochemistry and Molecular Biology, Egerton University, Njoro, Kenya.
authors.forename: Edwin
authors.initials: E
authors.lastname: Murungi
authors.affiliation: Biotechnology Research Institute, Kenya Agricultural and Livestock Research Organization, Kikuyu, Kenya.
authors.forename: Grace
authors.initials: G
authors.lastname: Murilla
authors.affiliation: South African National Bioinformatics Institute, University of the Western Cape, Cape Town, South Africa.
authors.forename: Alan
authors.initials: A
authors.lastname: Christoffels
authors.affiliation: Department of Epidemiology of Microbial Diseases, Yale School of Public Heath, New Haven, Connecticut, United States of America.
authors.forename: Serap
authors.initials: S
authors.lastname: Aksoy
authors.affiliation: Molecular Biology and Bioinformatics Unit, International Centre of Insect Physiology and Ecology, Nairobi, Kenya.
authors.forename: Daniel
authors.initials: D
authors.lastname: Masiga
mesh_terms: D000818:Animals; D002633:Chemotaxis; D005260:Female; D049750:Genome, Insect; D019476:Insect Proteins / Q000235:genetics*; D008297:Male; D008969:Molecular Sequence Data; D014370:Tsetse Flies / Q000145:classification / Q000235:genetics* / Q000502:physiology
chemical_list: D019476:Insect Proteins