Dec 11, 2009 - Claremont, Calif. -

Considered a pest by some, the common fruit fly has led to notoriety for others, particularly researchers at Harvey Mudd College, who are using Drosophila melangaster (common fruit fly) as a model system to study the evolution of gene regulation during development.

Research papers, authored by Robert Drewell, assistant professor of biology, and his team of undergraduate researchers were published this fall in two leading peer-reviewed journals. The papers offer a better understanding of the genes that regulate intricate developmental processes in the embryo of the common fruit fly. Their findings offer important insights related to the understanding of gene regulation—including that in humans—during development and evolution.

Since all organisms use common genetic systems, understanding biological processes in the fruit fly, which has been used for genetic analysis since the early 1900s, helps scientists understand those same processes in other complex multicellular organisms.

The research paper, “Functional evolution of cis-regulatory modules at a homeotic gene in Drosophila” was published in the November online edition of PLoS Genetics and had over 1,000 views during the first month of its posting. The eight HMC student co-authors were Margaret C.W. Ho ‘08, Holly Johnsen ’07, Sara E. Goetz ’08, Benjamin J. Schiller ’08, Diana A. Tran ’10, Andrey S. Shur ’10, John M. Allen ’09 and Christoph Rau ’07.

The author’s summary of this paper reads:

The fertilized animal embryo is a mass of uniform cells that becomes a complex, segmented, and highly organized structure of differentiated cells through the process of development. This vital process is controlled by networks of developmental genes interacting with each other on the molecular level. Because these genes are crucial for animal development, they are conserved both in function and at the DNA sequence level in related species. We have examined critical DNA sequence modules which regulate genes that pattern the early embryo in different species of the fruit fly. We found that despite rapid evolution of the DNA sequences, the regulatory sequences from one fruit fly species are able to operate when tested in another fruit fly species. Further analysis reveals that there are sequences within these regulatory DNA modules which are conserved across different species and which are critical for regulatory function. These conserved sequences represent critical binding sites for protein transcription factors. These findings have important implications for our understanding of gene regulation during development and evolution across diverse animal species ranging from the fruit fly to humans.
Published online in December 2009 in the journal Development was a related Primerarticle “Dissecting the regulatory switches of development: lessons from enhancer evolution in Drosophila” co-authored by Drewell, Tran, Ho and Matthew J. Borok ’09.

Drewell’s research is funded by a grant from the National Institues of Health and a recent $600,000 National Science Foundation (NSF) CAREER grant. Drewell is also developing an integrated curriculum and various educational tools that merge molecular and developmental biology, genetics and evolution. He is testing the hypothesis that research can attract and retain talented students in careers in science through enhancement of the undergraduate experience. The funding also allows Drewell to continue to actively recruit and engage student researchers, especially those from traditionally underrepresented groups in science.