Feature
Breaking Down a Bacterium
February 5, 2007
IU biologist David Kehoe has received an NSF grant to sequence the genome of one complex bacterium
Fremyella diplosiphon is one of the cyanobacteria, a diverse and populous division of microorganisms once referred to as "blue-green algae."
Last September, Indiana University Bloomington biologist David Kehoe, working with geneticists at the Baylor College of Medicine in Houston, got a half million dollar grant from the National Science Foundation (NSF) to study the genome of a bacterium that changes color under various light and nutrient conditions.
Why is it worth spending so much money on something seemingly so far removed from most people's daily lives?
"This is basic research, and from a scientific perspective there's great value in that," said Kehoe.
"But practically speaking, studying this bacterium [Fremyella diplosiphon] is important, for one thing, because sequencing its genome will help us understand many other bacterial species, and from a health and medical standpoint that's well worth knowing."
There are more bacteria in our bodies than cells. Bacteria colonizing our guts are vital for digestion. And, of course, many types of bacteria cause disease. The bacterium Kehoe is studying is one of the most complex, having more than 10,000 genes.
The understanding of many bacteria that will come from sequencing this one is vital, Kehoe said, given that many bacteria, particularly ones that cause disease in humans, are difficult to study in the lab. Kehoe's work could bring scientists closer to learning more about those elusive disease-causing bacteria, too.
Kehoe's research is made possible by advancements in gene sequencing technology. Only several years ago, Kehoe said, the most powerful gene sequencing machines could process several thousand base pairs of DNA, the building blocks of genes. Today, Kehoe and his colleagues have access to technology that allows them to sequence up to 20 million such base pairs during a single analysis. Soon that number could jump to 100 million base pairs. (Base pairs are the complementary units, called nucleotides, that are connected to each other to form the spiral structure of DNA.)
The rapid pace of technological and scientific innovation, Kehoe said, presents both opportunities and challenges.
"Americans are bombarded with facts, about everything from which diets work best to whether or not Pluto is a planet, and it can be disquieting to Americans when they learn that the outcomes of science are never complete and always controversial," he said.
As part of the NSF grant, Kehoe will do his part to make science more accessible by teaching for several weeks at the Harmony School in Bloomington. He will work with students there not only about bacteria and genetics, but also about broader social issues. "I think it's important for kids to learn about this stuff," Kehoe said. "Pretty soon everyone will be able to have their genome sequenced, but what do we do with all that information? It sounds like a good idea to use it to look at genes that might make you susceptible to certain kinds of cancer. But do we also make that information available to insurance companies? It's easy to get into all sorts of ethical dilemmas."
