Lauren N Gresham, Sumant Grover, Victoria Rene Spradling



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Understanding the genetic and molecular underpinnings for morphological diversity remains a central goal of evolutionary and developmental biology research. While it is now understood that these traits arise by the orchestrated expression of numerous genes, a so called gene regulatory network, what remains poorly understood is how these networks of genes and their expression patterns are initially assembled and subsequently diversify. Gene expression is controlled by DNA sequences that are often referred to as cis-regulatory elements (CREs). Each CRE possesses binding sites for transcription factor proteins whose cumulative binding results in a specific pattern of gene expression. It is anticipated that gene expression evolution frequently occurs through the formation, modification, and destruction of CREs, presumably through changes that create or remove binding sites for transcription factor proteins. However the binding site level of CRE evolution has been worked out in very few cases. The fruit fly species Drosophila melanogaster has a male-specific pattern of abdominal pigmentation for which the enzyme encoding genes and several of their upstream transcription factor regulators are known. However, the details of how these regulators interact with CREs remain largely uncharacterized. One such enzyme gene that is necessary for this species’ pattern of pigmentation is Dopa decaboxylase (Ddc). Here we share the results of our efforts to uncover the CRE-basis for this gene’s expression pattern, and how this regulation and pattern of expression has evolved during the origin and diversification of this male-specific trait. Success here will advance a leading model for the CRE and gene network basis for morphological diversity.

Publication Date


Project Designation

Independent Research - Graduate

Primary Advisor

Thomas M. Williams

Primary Advisor's Department



Stander Symposium project

The modification of a pleiotropic cis-regulatory element shaped the contribution of Ddc to a novel dimorphic pigmentation trait.