Date of Award

Spring 1998

Document Type

Restricted Thesis

Terms of Use

© 1998 Eric A. Falke. All rights reserved. Access to this work is restricted to users within the Swarthmore College network and may only be used for non-commercial, educational, and research purposes. Sharing with users outside of the Swarthmore College network is expressly prohibited. For all other uses, including reproduction and distribution, please contact the copyright holder.

Degree Name

Bachelor of Arts


Biology Department

First Advisor

Kathleen King Siwicki


A molecular clock involving the period protein (Per) regulates circadian rhythms of eclosion and locomotor activity in Drosophila melanogaster. Cellular localization studies address the question of where the rhythmic expression of per might act to produce rhythmic behavior. These studies show that per is strongly and rhythmicly expressed in tissues in the central nervous system and the ring gland. Daily rhythms of per expression have been monitored in cultured complexes of the pupal central nervous system and ring gland utilizing a per-luciferase reporter gene, plo. Per expression is monitored as the number of photons emitted by the luciferase reaction. Another reporter gene, BG-luc, has higher amplitude luciferase rhythms in whole flies. However, CNS-RG complexes from BG-luc strains showed far fewer circadian rhythms than plo strains monitored under the same conditions. Changes in the culture media, culturing temperature, treatment with cycles of light and dark, and light and dark cycles combined with temperature cycles did not effect this difference in the percentage of preparations that showed circadian rhythms of expression. Additonally, different culturing conditions produced no improvement in the percentage of rhythmic preparations observed for several strains of BG-luc and plo flies.