Date of Completion


Degree Type

Honors Thesis - Campus Access


Biology (BIOL)

First Advisor

Cathy McElwain


Stem cells play an integral role in the maintenance of adult tissues because of their ability to differentiate into a number of cell types. Despite the prominence of stem cell research, relatively little is known about the effects of aging on stem cells in the germline. The Drosophila melanogaster male germline serves as an ideal model because the fates of germline stem cells (GSCs) can be followed in the progeny. This study investigates GSC loss and replacement during aging by examining germ line distribution by utilizing sequential mating methods. Using a maternally derived Gal-4 Flipase Recombination Enzyme (FLP) to flip-out a Flipase Recognition Target (FRT}flanked sequence interrupting the green fluorescent protein (GFP) gene, we have created male germlines mosaic for GFP expression. Similarly, some GSCs and all the progeny that result from fertilization by the sperm derived from these GSCs do not express GFP. By determining the distribution of GFP-expressing progeny of a given male, we can deduce the distribution of GFP-expressing stem cells. Utilizing this system, we were able to assess trends in stem cell populations as males aged.