Persistence of Adh gene in the environment, in Drosophila pupae, and in the mite Proctolaelaps regalis

There is substantial evidence supporting the horizontal gene transfer of DNA (P mobile elements) from Drosophila willistoni to Drosophila melanogaster. A potential vector of this transfer is the mite F^octolaelaps regalis. The mite is hypothesized to acquire DNA while feeding on flies and to carry and transmit that DNA to subsequent prey. This research concerns the persistence and longevity of DNA in the respective environmental components. Separate experiments were run testing: (1) the persistence of DNA in the environment using agar blocks as the substratum, (2) the persistence of DNA in Drosophila pupae after microinjection of the DNA, and (3) the persistence of DNA in the mite, Proctolaelaps regalis after feeding. A surrogate for the P element was used in the experiments in the form of a recombinant plasmid with a mammaUan alcohol dehydrogenase insert (Adh-V). The Adh-V signal was detected in the environment up to and including 14 days, in developing pupae up to the time of emergence and in emerged adults, and in the mite up to and including 60 hours. The data generated from these experiments provides estimates of the time frame in which a mite can potentially acquire, retain, and be competent to transfer genetic material among eukaryotes upon which it feeds.