Transposable elements of the mariner family in the tephritid fruit fly, Bactrocera tryoni

The research outlined in this thesis primarily focused on the isolation and characterization of representatives of the mariner family of transposable elements in the genome of the tephritid, Bactrocera tryoni (Queensland fruit fly). A preliminary investigation was also made of the mobility properties of constructs based on the mariner element Mos], following their transient introduction into the embryonic soma of B. tryoni. This involved the use of plasmid-based excision and transposition assays. These studies were partly undertaken to obtain an initial idea of the feasibility of developing a germline transformation system based on particular mariner elements for use with B. tryoni, and possibly other related tephritids. To investigate whether the B. tryoni genome contained endogenous mariner element copies, an initial PCR analysis was carried out using degenerate oligonucleotide primers that had previously been designed to stretches of conserved residues within transposases encoded by particular mariner elements. Using this approach, examples of at least five distinct types of mariner elements were detected in the genome of B. tryoni following the cloning and DNA sequencing of 20 unique amplified fragments. Phylogenetic analyses using the conceptual amino acid translations of these partial transposase gene regions indicated that the B. tryom‘ sequences represented three subfamilies of mariner elements. Using the same PCR-based approach, diverse mariner sequences were also isolated from Bactrocera neohumeralis, a sibling species of B. tryoni, and an additional tephritid, Bactrocera jarvisi