Studying marine organisms could solve mysteries of disease
 
Denizens of the deep

hat can a toadfish teach us about liver disease? Can a minnow help cure an ailing heart? How can a sea slug help improve memory?

Through the Marine and Freshwater Genomics Initiative, a group of University of Miami scientists is trying to answer these important questions and many others.

By studying the genomes of marine organisms and their ability to adapt to certain extreme conditions, these scientists are pushing the envelope in an effort to solve some of the mysteries surrounding human diseases, as well as solve specific environmental problems that prove harmful to humans.Using the same DNA sequencing technology used to decode the human genome, investigators are attempting to identify the function of genes in marine species such as the gulf toadfish, California Sea Hare, bicolor damselfish, and other denizens of the deep. Their goal is to understand how those genes are coordinated to respond to the environment.

Because many marine organisms can often adapt to more extreme environments than mammals, they can show scientists the types of genomic novelties that they use to make these adaptations and how they might have clinical applications.

“I always come back to the toadfish as a good example,” says Patrick J. Walsh, professor of marine biology and fisheries at the Rosenstiel School of Marine and Atmospheric Science and one of the initiative’s principal investigators. “Toadfish are very tolerant of high ammonia levels. If we can figure out how they tolerate ammonia, we might be able to duplicate this in a clinical setting to help patients with hepatic encephalopathy, a suite of liver diseases that causes blood ammonia to rise and which ultimately causes brain damage, coma, and death.”
 

 
Walsh says there are dozens of other examples of such “champions” of resistance, such as the California Sea Hare, or Aplysia, whose very simple brain makes it a popular model in the neurosciences for the study of memory and learning, and a type of minnow that may provide answers to unsolved questions about cardiac function.

“It turns out that fish in the north have metabolically more active hearts than fish in the south,” says Douglas Crawford, director of marine genomics at the Rosenstiel School. “So we can use genomic tools to investigate these differences in gene expressions that affect heart function.”

The initiative also is addressing environmental problems, such as knowing what type of bacteria, algae, or other harmful microbes are present in water.

In collaboration with Richard Bookman, director of UM’s DNA Microarray Core Facility and an associate professor of molecular and cellular pharmacology in the School of Medicine, Walsh also is investigating the impact of toxic compounds on the entire genome. “By taking a genomic approach to the interaction of marine toxins with, for example, mammals like laboratory mice, we can try to pick up some of these early warning signs that are too subtle to obviously appear as symptoms or complaints of a patient,” Bookman says.

A slew of other applications, such as improving fisheries management, also are possible through the study of marine genomics. Says Linda Farmer, director of the College of Arts and Sciences Marine and Atmospheric Science Program, who also is involved in the initiative: “If we know how stocks are related and their patterns of movement and reproduction, they can be much more effectively managed.”