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Animal development proceeds by continuously changing patterns of gene expression, where patterns are controlled by a type of DNA sequence known as a cis-regulatory element (CRE). How gene expression patterns are encoded in DNA sequence remains poorly understood. My thesis research studied a CRE, known as the t_MSE, which controls the male-specific expression pattern for the Drosophila melanogaster gene known as tan. This expression pattern is required for this species male-specific pigmentation, and the pattern is modified or absent in related fruit fly species. I isolated and evaluated this CRE's sequence and gene regulatory activity from various species and populations. My results pinpointed the evolutionary origin of the t_MSE and showed a surprising case of introgression between two sympatric species. These results make possible future studies to identify which sequence changes are responsible for this CRE's nascence and what the adaptive significance might be for its introgression.

Publication Date


Project Designation

Honors Thesis

Primary Advisor

Thomas M. Williams

Primary Advisor's Department



Stander Symposium poster

Research exercise: The Ancestry and Evolution of the Fruit Fly t_MSE Cis-Regulatory Element