Dissertation Research: Phylogenetic Analysis of the Drosophila Montium Subgroup: Horizontal and Vertical Transmission of Mobile Elements

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9423508 SIMMONS This study will examine the evolution of a jumping gene, called hobo in a group of fruit flies. Jumping genes are portions of the genetic sequence which function independently within an organism's (host's) genome. Jumping genes move along chromosomes on their own. Due to their mobility, hobo elements have been known to unfavorably alter the functioning of genes within their host. Jumping genes are found to be present in substantial numbers across a wide variety of organisms, including humans. Because jumping genes move and function independently of other genes they are not always inherited in the usual manner from parent to offspring across generations. Instead jumping genes can be transmitted across species, even distantly related ones (e.g., from plants to animals) like a disease. This infectious mode is termed horizontal transmission. Jumping genes have been known to infect the chromosomes of distantly related species of fruit flies, which makes the flies a good model system for examing effects of jumping genes. However, in order to determine the inheritance pattern for a jumping gene one must first know the relationships (taxonomy) of the host species. This project's first goal will be to establish the relationships between species of fruit flies of the Drosophlia montium subgroup which are closely related to Drosophlila melanogaster. Drosophila melanogaster has been an organism intensively studied in order to understand the function of genes in all eukaryotes, including humans. Yet, in contrast, the taxonomy of this group of drosophilids is relatively unknown. The investigators will determine the taxonomy of these fruit fly species by using some features of their morphology and the DNA sequences of their genes. Once the fruit fly taxonomy is established, the presence or absence of the hobo element can be related to the taxonomy in order to infer the evolutionary history of the hobo elements.