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Greg Dewey explains network theory

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The President’s Dining Room was nearly full Monday for Interim Provost Greg Dewey’s lecture, “Network Theory in Biology.” Dewey’s lecture compared social networks and relationships between genes in biological systems. He also explained the significance of his research and how the application of his work employed the network theory to examine cancer biology. / photo by Jakeh Landrum

Brittany Lawrence
Staff Writer

Greg Dewey, interim provost and professor of chemistry, conducted a faculty lecture titled “Network Theory in Biology,” on Monday in the President’s Dining Room.

Roughly 40 students and faculty filled the President’s Dining Room for Dewey’s talk.

“My main point was to use the network theory to explore relations between biology data to see how one gene affects another,” Dewey said.

Dewey used a PowerPoint to aid his presentation visually. The presentation started off with a slide of acknowledgments which included collaborators and funding.

He began by explaining what the network theory was.

“The network theory is a way of coping and visualizing data,” Dewey said.

The basics are nodes and edges. A node can be described as an intersecting or connecting point. Edges are what connect the nodes.

Dewey used examples that were easy to understand.

One example he presented dealt with a social network.

He said that in this network the nodes would be people and the relationships they had would be the edges.

In another he stated that if transportation were the network then bus depots would be the nodes and routes would be the edges.

In his PowerPoint Dewey named four goals of the network theory: Visualization of a large complex system; Data Mining: Dealing with the data avalanche; Origins and growth of networks; Robustness and vulnerability of networks.

A chemist, Dewey is also interested in biology.

“I am interested in biological networks,” Dewey said.

He went over the three types of biological networks which included: genome, proteome, and metabolism.

He then went on to discuss the six degrees of separation, which basically means that everyone is around six steps away from any other person.

It is a small world network.

Again Dewey applied the concept of connectors in simple examples like Facebook, actors and traveling. Networks can expand by the addition of new nodes. His research included an analysis of gene expression and how one gene influences another. He came up with gene duplication models of network growth.

The application of this research was using the network theory to look at cancer biology.

The cancer network needs to be found, and then one must knock out the hubs.

Cancer can be caused by amplified genes.

“You don’t have to have gene amplification to have a cancer, but some cancers are a result of amplified genes,” Dewey said.

“Gene expression networks are hierarchical, connected and cliquish,” Dewey said.

The presentation was about an hour long and at the end the audience was able to ask Dewey questions.

“This lecture was totally different from other lectures I have attended,” Margo Cash, junior art history major, said.

“I liked the idea and the simple terms he used,” Cash said. “I liked the concept of the clique and the small world network and how everyone is connected.”

Dewey explained that the network theory can be used in a wide number of sciences. It is helpful when dealing with a big population.

“The network theory is a very powerful tool to visualize complicated systems,” Dewey said.

Brittany Lawrence can be reached at

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