Use of molecular genetics and functional genomics to: (i) Understand dichlorodiphenyltrichloroethane (DDT) resistance in Drosophila melanogaster and (ii) identify vulnerable target gene systems in Pediculus humanus humanus (body louse) and Callosobrucus maculatus (Cowepea weevil).

摘要

Recent advance in insect science has facilitated the understanding of complex insecticide metabolic systems and opened the possibility of finding new targets for managing insect populations. I discuss the use of molecular biology, population genetics and functional genomics to understand two mechanisms of DDT resistance in Drosophila melanogaster: target site insensitivity and metabolic resistance. In the first chapter, a study was carried out to test hyper-susceptibility of the Drosophila melanogaster parats-1 fly line towards several pyrethroids. A series of statistical tests allowed for the identification of a pesticide (deltamethrin) that decreased the frequency of the resistant parats-1 allele in a Drosophila population. In the second chapter, expression profiles were used to assess the extent to which gene transcription varies between laboratory and field selected DDT-resistant Drosophila (metabolic resistance). The second part of this thesis was focused on gene discovery in non-model organisms. Chapter three shows the identification and characterization of cowpea weevil proteases and amylases in a cDNA library containing gut-expressed genes, based on predicted enzyme catalytic sites and similarity analysis. Chapter four outlines the identification and description of genes putatively involved in protein catabolism and innate immune response in human body lice.